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Abstract Background In Australia in 2017, 89% of 15-year-old females and 86% of 15-year-old males had received at least one dose of the HPV vaccine. However, considerable variation in HPV vaccination initiation (dose one) across schools remains. It is important to understand the school-level characteristics most strongly associated with low initiation and their contribution to the overall between-school variation. Methods A population-based ecological analysis was conducted using school-level data for 2016 on all adolescent students eligible for HPV vaccination in three Australian jurisdictions. We conducted logistic regression to determine school-level factors associated with lower HPV vaccination initiation (

Background/Objectives : Given the discrepancies in immunisation coverage, the goal of this study was to explore the barriers and facilitators to effective communication across the school-based vaccination program in South Eastern Sydney schools. Methods : A qualitative study was undertaken with purposively selected immunisation staff, school coordinators, and parents of Year 7 students who had not received two vaccinations (dTpa and HPV) at school. A focus group with immunisation staff and interviews with school coordinators explored the barriers and facilitators to vaccination uptake, including communication across stakeholders. The parent interviews explored attitudes to vaccination and the school program and investigated the program communication methods. Results : Five immunisation staff, eleven school coordinators, and eleven parents participated in the study. The barriers to participation in the school vaccination program included low parent recall of vaccination information, challenges encountered by school staff in consent tracking, no communication channel between health staff and parents, a greater school focus on vaccination facilitation than student education, and limited communication between stakeholders about catch-up vaccinations. The facilitators included established school/parent relationships for vaccine communication, effective communication between health and school staff, and using multiple methods to promote clinic and consent requirements. Conclusions : Opportunities exist to increase program participation by enhancing vaccination information and education for students and parents, with better communication about vaccination catch-ups and consent.

School vaccination programs are crucial for achieving high immunisation coverage among adolescents, but substantial disparities exist across schools and regions. This ecological study aimed to determine associations between school characteristics and vaccination coverage for diphtheria-tetanus-acellular pertussis (dTpa) and human papillomavirus (HPV) vaccines among year 7 students in southeastern Sydney. An analysis of data from 70 mainstream schools participating in the 2019 South Eastern Sydney Local Health District School Vaccination Program utilised quasi-Poisson regression models to assess associations between vaccination coverage and school attendance, socio-educational status, Aboriginal enrolments, language background other than English (LBOTE), school sector (government, Catholic, or independent), and coeducation status. Median school coverage was 88% for dTpa, 88% for HPV-girls, and 86% for HPV-boys, with interquartile ranges of 82-93%, 84-92%, and 78-91%, respectively. Higher school attendance was associated with increased dTpa vaccination coverage (PR 1.14, 95% CI 1.02-1.27). Single-sex schools showed higher HPV vaccination coverage compared to coeducational schools for both girls (PR 2.24, 95% CI 2.04-2.46) and boys (PR 1.89, 95% CI 1.72-2.08). No significant associations were found for ICSEA, Aboriginal enrolments, LBOTE, or school sector. School attendance and coeducational status significantly influenced vaccination coverage, with differential impacts on dTpa and HPV vaccines. These findings highlight the need for targeted strategies to address disparities in school-based vaccination programs. Research using qualitative methods could be useful to understand the beliefs and attitudes contributing to these disparities in vaccine uptake so that programs can be tailored to maximise participation.

Abstract: In 2023, an increased number of urogenital and anorectal infections with Neisseria meningitis serogroup Y (MenY) were reported in New South Wales (NSW). Whole genome sequencing (WGS) found a common sequence type (ST-1466), with limited sequence diversity. Confirmed outbreak cases were NSW residents with a N. meningitidis isolate matching the cluster sequence type; probable cases were NSW residents with MenY isolated from a urogenital or anorectal site from 1 July 2023 without WGS testing. Of the 41 cases, most were men (n = 27), of whom six reported recent contact with a female sex worker. Five cases were men who have sex with men and two were female sex workers. Laboratory alerts regarding the outbreak were sent to all Australian jurisdictions through the laboratories in the National Neisseria Network. Two additional states identified urogenital MenY ST-1466 infections detected in late 2023. Genomic analysis showed all MenY ST-1466 sequences were interspersed, suggestive of an Australia-wide outbreak. The incidence of these infections remains unknown, due to varied testing and reporting practices both within and across jurisdictions. Isolates causing invasive meningococcal disease (IMD) in Australia are typed, and there has been no MenY ST-1466 IMD recorded in Australia to end of March 2024. Concerns remain regarding the risk of IMD, given the similarity of these sequences with a MenY ST-1466 IMD strain causing a concurrent outbreak in the United States of America., (© Commonwealth of Australia CC BY-NC-ND.)

Objectives: To describe the impact of universal screening for coronavirus disease 2019 (COVID-19) on passengers on cruise ships docking in Sydney, Australia, during 2022 that experienced a significant outbreak of COVID-19. Type of program or service: Cruise ship disease surveillance Methods: Case series, based on analysis of cruise ship voyages where universal screening of passengers was requested by a NSW health authority and undertaken by the cruise ship., Results: Of 111 voyages in 2022, three fit the definition for this study. Universal screening during these voyages resulted in the detection of up to 1.8 times the number of existing COVID-19 cases, increasing attack rates of the three voyages from 14% to 24%; 13% to 28%; and 3% to 8% respectively. Case demographics showed an even gender distribution, with a majority 70 years or older. Asymptomatic case percentage ranged from 2% to 54%, with age and gender not associated with symptomatic status. Almost all cases were reported as being fully vaccinated. Genomic testing of cases showed multiple lineages of COVID-19 circulating in all three voyages., Lessons Learnt: Public health authorities, the cruise industry and passengers should be aware that a large number of unidentified cases of COVID-19 may disembark from a cruise ship that has experienced a large outbreak of the virus. These cases can seed the infection into vulnerable communities. Universal screening as part of the response to a significant outbreak will help identify cases and limit the spread of COVID-19., Competing Interests: None declared

In April 2021, the South Eastern Sydney Local Health District Public Health Unit (Sydney, New South Wales, Australia) was notified of 3 patients with Pseudomonas aeruginosa infections secondary to skin piercings performed at the same salon. Active case finding through laboratories, clinician alerts, and monitoring hospital visits for piercing-related infections identified additional cases across New South Wales, and consumers were alerted. We identified 13 confirmed and 40 probable case-patients and linked clinical isolates by genomic sequencing. Ten confirmed case-patients had used the same brand and batch of aftercare solution. We isolated P. aeruginosa from opened and unopened bottles of this solution batch that matched the outbreak strain identified by genomic sequencing. Piercing-related infections returned to baseline levels after this solution batch was recalled. Early outbreak detection and source attribution via genomic sequencing are crucial for controlling outbreaks linked to contaminated products. Manufacturing standards for nonsterile cosmetic products and guidance for piercing aftercare warrant review.

Background: Transmission of coronavirus disease 2019 (COVID-19) has been demonstrated in fitness settings internationally. We report the first documented case of transmission of COVID-19 in a gymnasium in Australia in 2020., Methods: Case finding and case interviews were conducted among attendees in a Western Sydney gymnasium, Australia. Whole genome sequencing using an amplicon-based approach was performed on all SARS CoV-2 polymerase chain reaction positive samples detected through surveillance., Results: We show that five cases of COVID-19 were linked to the gymnasium, with transmission occurring on 7 July 2020, when the index case transmitted the infection to four other gymnasium attendees through the sharing of an enclosed space., Conclusions: There is an ongoing risk of transmission of COVID-19 within gymnasium environments and they are justifiably classified as a 'high-risk' venue. There may be a need to expand ventilation and space requirements to prevent transmission of COVID-19 in such settings in the context of severe COVID-19 variants or to prevent respiratory disease transmission in general., (© Commonwealth of Australia CC BY-NC-ND)

Objective: To identify and control a source of Legionella in Sydney CBD., Methods: Clinical, epidemiological, environmental and genomic techniques were employed to identify cases and the source of Legionella., Results: Eleven legionellosis cases were linked to Sydney CBD with a median age of 69 years. All were hospitalised and had risk factors for Legionella infection. Eight of 11 cases identified as male. Genomic analysis linked three cases to a contaminated cooling water source in Sydney CBD, with a further case infected with a similar strain to that found in Sydney CBD. Another case, although epidemiologically linked to Sydney CBD, was infected with a genomically different strain to that found in Sydney CBD. Six other cases had no viable sample for genomic analysis., Conclusion/implications for Public Health: An outbreak of legionellosis is a serious public health threat that requires rapid investigation and environmental control. We were able to identify a source in Sydney CBD through the application of clinical, epidemiological, environmental and genomic techniques. Genomic analysis is a powerful tool that can be used to confirm the source location but requires close collaboration between clinicians, public health units and microbiologists to recover viable sputum cultures from cases diagnosed with legionellosis., (Crown Copyright © 2023. Published by Elsevier B.V. All rights reserved.)

Background: Previous Australian studies have shown that delayed vaccination with each of the three primary doses of diphtheria-tetanus-pertussis-containing vaccines (DTP) is up to 50 % in certain subpopulations. We estimated the excess burden of pertussis that might have been prevented if (i) all primary doses and (ii) each dose was given on time., Methods: Perinatal, immunization, pertussis notification and death data were probabilistically linked for 1 412 984 infants born in two Australian states in 2000-12. A DTP dose administered >15 days after the recommended age was considered delayed. We used Poisson regression models to compare pertussis notification rates to 1-year of age in infants with ≥1 dose delayed (Aim 1) or any individual dose delayed (Aim 2) versus a propensity weighted counterfactual on-time cohort., Results: Of all infants, 42% had ≥1 delayed DTP dose. We estimated that between 39 to 365 days of age, 85 (95% CI: 61-109) cases per 100 000 infants, could have been prevented if all infants with ≥1 delayed dose had received their three doses within the on-time window. Risk of pertussis was higher in the delayed versus the on-time cohort, so crude rates overestimated the excess burden (110 cases per 100 000 infants (95% CI: 95-125)). The estimated dose-specific excess burden per 100 000 infants was 132 for DTP1, 50 for DTP2 and 19 for DTP3., Conclusions: We provide robust evidence that improved DTP vaccine timeliness, especially for the first dose, substantially reduces the burden of infant pertussis. Our methodology, using a potential outcomes framework, is applicable to other settings., (© The Author(s) 2022. Published by Oxford University Press on behalf of the International Epidemiological Association.)

Abstract: The standard practice of blood borne virus (BBV) follow-up in New South Wales is a passive approach of general-practitioner-led testing. The value of this approach is unknown. We undertook an active contact tracing method with the aims of investigating a potential hepatitis B source, along with accurately measuring the participation rate, to consider the value of this and other follow-up methods for future BBV investigations. Investigation of a newly-acquired hepatitis B infection was undertaken at a dental practice identified as a possible exposure site. To screen for hepatitis B infection among potential source or co-exposed clients, we actively followed up with staff and clients of the practice to request they undertake hepatitis B serology. Eligible staff and clients received up to four phone calls and were provided with a pathology request form by the public health unit (PHU). Access to free serology was offered to people who did not have access to Medicare. Reminder calls were made if serology results were not received by the PHU. As the ordering doctor, the public health physician was responsible for providing results and referring for follow-up care. Of 160 clients, 63 (39%) undertook hepatitis B serology. Of these 63, none were found to have hepatitis B infection. It was estimated the active investigation involved an extra 430 hours of PHU staff time at a cost in Australian dollars of $30,000. Active follow-up allows an accurate participation rate to be documented. Despite intense active follow-up, only 39% of clients undertook testing, bringing into question the yield of the usual approach in which active follow-up of potential mass BBV exposures is not undertaken. While active follow-up is resource intensive, it should be considered where the risks and consequences from the BBV infection are high., (© Commonwealth of Australia CC BY-NC-ND.)

Objective: To assess the usability of a self-assessment COVID-19 exposure tool for workplaces., Methods: A COVID-19 exposure tool for workplaces was developed using five risk criteria. Public Health Unit (PHU) assessors who administered the tool documented when they administered the tool, the time taken for finalisation of the assessment and ease of administration. The System Usability Scale was used for workplace managers' perceptions on tool use. Data were assessed using both quantitative and qualitative analysis., Results: Eighty-four workplaces used the tool to assess COVID-19 exposure risk. Of those, the outcome provided by the tool did not require modification by the PHU assessor in 70% of workplaces. Eighty per cent of the assessments were completed by the next day. PHU assessors rated the overall ease of administration of the tool as 'easy' or 'very easy' for 85% of workplaces and indicated they would employ the tool across a number of settings including complex workplaces. The mean System Usability Scale was 82. Workplace managers were predominately positive regarding its suitability., Conclusion: The tool provides an easy-to-use assessment of SARS-CoV-2 exposure in the workplace., Implications for Public Health: The tool's adoption will empower workplace managers and improve the capacity of public health units to prevent further transmission of SARS-CoV-2 in workplaces., (© 2022 The Authors.)

Background: In Australia in 2017, 89% of 15-year-old females and 86% of 15-year-old males had received at least one dose of the HPV vaccine. However, considerable variation in HPV vaccination initiation (dose one) across schools remains. It is important to understand the school-level characteristics most strongly associated with low initiation and their contribution to the overall between-school variation., Methods: A population-based ecological analysis was conducted using school-level data for 2016 on all adolescent students eligible for HPV vaccination in three Australian jurisdictions. We conducted logistic regression to determine school-level factors associated with lower HPV vaccination initiation (< 75% dose 1 uptake) and estimated the population attributable risk (PAR) and the proportion of schools with the factor (school-level prevalence)., Results: The factors most strongly associated with lower initiation, and their prevalence were; small schools (OR = 9.3, 95%CI = 6.1-14.1; 33% of schools), special education schools (OR = 5.6,95%CI = 3.7-8.5; 8% of schools), higher Indigenous enrolments (OR = 2.7,95% CI:1.9-3.7; 31% of schools), lower attendance rates (OR = 2.6,95%CI = 1.7-3.7; 35% of schools), remote location (OR = 2.6,95%CI = 1.6-4.3; 6% of schools,) and lower socioeconomic area (OR = 1.8,95% CI = 1.3-2.5; 33% of schools). The highest PARs were small schools (PAR = 79%, 95%CI:76-82), higher Indigenous enrolments (PAR = 38%, 95%CI: 31-44) and lower attendance rate (PAR = 37%, 95%CI: 29-46)., Conclusion: This analysis suggests that initiatives to support schools that are smaller, with a higher proportion of Indigenous adolescents and lower attendance rates may contribute most to reducing the variation of HPV vaccination uptake observed at a school-level in these jurisdictions. Estimating population-level coverage at the school-level is useful to guide policy and prioritise resourcing to support school-based vaccination programs., (© 2022. The Author(s).)

Objectives: To assess the extent to which the 2018-19 New South Wales summer influenza epidemic was associated with overseas or domestic travel and with seasonal influenza vaccination status., Design, Setting: Unmatched case-control study, based on an online survey distributed from the NSW Notifiable Conditions Information Management System (NCIMS) to people for whom mobile phone numbers were available., Participants: A case was defined as a person with notified laboratory-confirmed influenza with onset of illness between 1 December 2018 and 21 March 2019. People with notified pertussis infections (confirmed or probable) were selected as controls., Main Outcome Measures: Notified influenza infection, by travel and contact with unwell overseas travellers in the week before onset of illness and seasonal influenza vaccination status (as the primary exposures)., Results: Valid survey responses were provided by 648 of 2806 invited people with notified influenza (23%) and 257 of 796 invited people with notified pertussis (32%). The demographic characteristics of the respondents were similar to those of the source population (7251 cases, 2254 controls). During the first two months of the summer of 2018-19, notified influenza was more likely for people who had travelled overseas or had contact with an ill overseas traveller in the week before symptom onset (adjusted OR [aOR], 6.99; 95% CI, 3.59-13.6), but not during the second two months (aOR, 1.63; 95% CI, 0.79-3.35). Influenza vaccination status was not associated with the likelihood of notified influenza., Conclusions: Travel-related factors were early drivers of the 2018-19 NSW summer influenza epidemic; local transmission sustained the outbreak despite unfavourable conditions later in summer. Our findings prompted re-evaluation of recommendations for pre-travel vaccination in NSW. The role of travel in out-of-season influenza outbreaks should be considered in other temperate zones., (© 2021 AMPCo Pty Ltd.)

Background: Australian adolescents are routinely offered HPV and dTpa (diphtheria, tetanus, pertussis) vaccines simultaneously in the secondary school vaccination program. We identified schools where HPV initiation was lower than dTpa coverage and associated school-level factors across three states., Methods: HPV vaccination initiation rates and dTpa vaccination coverage in 2016 were calculated using vaccine databases and school enrolment data. A multivariate analysis assessed sociodemographic and school-level factors associated with HPV initiation being >5% absolute lower than dTpa coverage., Results: Of 1280 schools included, the median school-level HPV initiation rate was 85% (interquartile range (IQR):75-90%) and the median dTpa coverage was 86% (IQR:75-92%). Nearly a quarter (24%) of all schools had HPV vaccination initiation >5% lower than dTpa coverage and 11 % had >10% difference. School-level factors independently associated with >5% difference were remote schools (aOR:3.5, 95% CI = 1.7-7.2) and schools in major cities (aOR:1.8, 95% CI = 1.0-3.0), small schools (aOR:3.3, 95% CI = 2.3-5.7), higher socioeconomic advantage (aOR:1.7, 95% CI = 1.1-2.6), and lower proportions of Language-background-other-than-English (aOR:1.9, 95% CI = 1.2-3.0)., Conclusion: The results identified a quarter of schools had lower HPV than dTpa initiation coverage, which may indicate HPV vaccine hesitancy, and the difference was more likely in socioeconomically advantaged schools. As hesitancy is context specific, it is important to understand the potential drivers of hesitancy and future research needs to understand the reasons driving differential uptake.

Background: Schools are the primary setting for the delivery of adolescent HPV vaccination in Australia. Although this strategy has achieved generally high vaccination coverage, gaps persist for reasons that are mostly unknown. This study sought to identify school-level correlates of low vaccination course initiation and completion in New South Wales, Tasmania, and Western Australia to inform initiatives to increase uptake., Methods: Initiation was defined as the number of first doses given in a school in 2016 divided by vaccine-eligible student enrolments. Completion was the number of third doses given in a school in 2015-2016 divided by the number of first doses. Low initiation and completion were defined as coverage ≤ 25thpercentile of all reporting schools. We investigated correlations between covariates using Spearman's rank correlation coefficients. Due to multicollinearity, we used univariable logistic regression to investigate associations between school characteristics and low coverage., Results: Median initiation was 84.7% (IQR: 75.0%-90.4%) across 1,286 schools and median completion was 93.8% (IQR: 86.0%-97.3%) across 1,295 schools. There were strong correlations between a number of school characteristics, particularly higher Indigenous student enrolments and lower attendance, increasing remoteness, higher postcode socioeconomic disadvantage, and smaller school size. Characteristics most strongly associated with low initiation in univariate analyses were small school size, location in Tasmania, and schools catering for special educational needs. Low completion was most strongly associated with schools in Tasmania and Western Australia, remote location, small size, high proportion of Indigenous student enrolments, and low attendance rates., Conclusion: This study provides indicative evidence that characteristics of schools and school populations are associated with the likelihood of low initiation and completion of the HPV vaccination course. The findings will guide further research and help target initiatives to improve vaccination uptake in schools with profiles associated with lower coverage., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Objective: To explore the factors associated with the transmission of SARS-CoV-2 to patrons of a restaurant., Methods: A retrospective cohort design was undertaken, with spatial examination and genomic sequencing of cases. The cohort included all patrons who attended the restaurant on Saturday 25 July 2020. A case was identified as a person who tested positive to a validated specific Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) nucleic acid test. Associations were tested using chi-squared analysis of case versus non-case behaviours., Results: Twenty cases were epidemiologically linked to exposure at the restaurant on 25 July 2020. All cases dined indoors. All cases able to be genomic sequenced were found to have the same unique mutational profile. Factors tested for an association to the outcome included attentiveness by staff, drink consumption, bathroom use and payment by credit card. No significant results were found., Conclusion: Indoor dining was identified as a key factor in SARS-CoV-2 transmission, and outdoor dining as a way to limit transmission. Implications for public health: This investigation provides empirical evidence to support public health policies regarding indoor dining., (© 2021 The Authors.)

Objectives: To describe local operational aspects of the coronavirus disease 2019 (COVID-19) response during the first three waves of outbreaks in New South Wales (NSW), Australia, which began in January, July and December 2020. Type of program or service: Public health outbreak response., Methods: Narrative with epidemiological linking and genomic testing., Results: Epidemiological linking and genomic testing found that during the first wave of COVID-19 in NSW, a large number of community transmissions went undetected because of limited testing for the virus and limited contact tracing of cases. The second wave of COVID-19 in NSW emerged following reintroduction from the second wave in Victoria, Australia in July 2020, and the third wave followed undetected introduction from overseas. By the second and third waves, cases could be more effectively detected and isolated through an increased ability to test and contact trace, and to rapidly genomic sequence severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) isolates, allowing most cases to be identified and epidemiologically linked. This greater certainty in understanding chains of transmission resulted in control of the outbreaks despite less stringent restrictions on the community, by using a refined strategy of targeted shutdown, restrictions on cases, their close contacts, identified hotspots and venues of concern rather than a whole of community lockdown. Risk assessments of potential transmission sites were constantly updated through our evolving experience with transmission events. However, this refined strategy did leave the potential for large point source outbreaks should any cases go undetected. [Addendum] A fourth wave that began in Sydney in June 2021 challenged this strategy due to the more transmissible nature of the Delta variant of SARS-CoV-2., Lessons Learnt: A wave of COVID-19 infections can develop quickly from one infected person. The community needs to remain vigilant, adhering to physical distancing measures, signing in to venues they visit, and getting tested if they have any symptoms. Signing out of venues on exit allows public health resources to be used more efficiently to respond to outbreaks., Competing Interests: None declared.

Background: This study describes trends in social inequities in first dose measles-mumps-rubella (MMR1) vaccination coverage in Western Australia (WA) and New South Wales (NSW). Using probabilistically-linked administrative data for 1.2 million children born between 2002 and 2011, we compared levels and trends in MMR1 vaccination coverage measured at age 24 months by maternal country of birth, Aboriginal status, maternal age at delivery, socio-economic status, and remoteness in two states., Results: Vaccination coverage was 3-4% points lower among children of mothers who gave birth before the age of 20 years, mothers born overseas, mothers with an Aboriginal background, and parents with a low socio-economic status compared to children that did not belong to these social groups. In both states, between 2007 and 2011 there was a decline of 2.1% points in MMR1 vaccination coverage for children whose mothers were born overseas. In 2011, WA had lower coverage among the Aboriginal population (89.5%) and children of young mothers (89.3%) compared to NSW (92.2 and 92.1% respectively)., Conclusion: Despite overall high coverage of MMR1 vaccination, coverage inequalities increased especially for children of mothers born overseas. Strategic immunisation plans and policy interventions are important for equitable vaccination levels. Future policy should target children of mothers born overseas and Aboriginal children.

Objective: To investigate an outbreak of COVID-19 in Sydney, Australia., Methods: Epidemiological linking and analysis of cases of COVID-19 across multiple outbreak sites., Results: Fifteen cases of COVID-19 and 41 contacts were identified and linked in a cluster that included one workplace and five households. The mean incubation period in the cases ranged from 4.6 to 6.4 days, while the median incubation period was shorter, ranging from 3 to 5 days. The overall range of incubation periods was 2 to 12 days. Differential attack rates were found within households (86% adults vs. 9% children) and workplace (32%) settings. Conclusions and implications for public health: Our investigation links cases between multiple households and a workplace. When exploring these links using a rapid workplace assessment, real-time cluster data along with objective measurements of exposure, such as with the Australian Government COVIDSafe app, may have allowed these links to be identified more readily and potentially reduced further spread of COVID-19. We found age as a factor for infection, with children being less likely to both acquire SARS-CoV-2 infection and to develop symptoms. This finding aids in our understanding of how the virus affects children and cautiously supports face-to-face classroom teaching., (© 2021 The Authors.)

Background: Receiving vaccines at or close to their due date (vaccination timeliness) is a now key measure of program performance. However, studies comprehensively examining predictors of delayed infant vaccination are lacking. We aimed to identify predictors of short and longer-term delays in diphtheria-tetanus-pertussis (DTP) vaccination by dose number and ethnicity., Methods: Perinatal, notification, death and immunisation databases were linked for 1.3 million births in 2000-11 from two Australian states (Western Australia and New South Wales), with follow-up data until 2013. Ordinal logistic regression was used to estimate adjusted relative risks (RR) by degree of delay. Separate models were constructed for each vaccine dose and for Aboriginal and non-Aboriginal children., Results: Each dose-specific cohort included at least 49,000 Aboriginal and 1.1 million non-Aboriginal children. Delayed receipt was more common among Aboriginal than non-Aboriginal children (eg for the first dose of DTP [DTP1] 19.4 v 8.1%). Risk factors for delayed vaccination were strongest for DTP1, and delayed receipt of DTP1 was a key driver of subsequent delays; every week DTP1 was delayed was associated with a 1.6 to 2-fold increased risk of delayed DTP2 receipt. For DTP1, ≥3 previous pregnancies (the only factor more strongly associated with longer than shorter delays; RR ≥5 compared to no previous pregnancies), and children born to mothers <20 years of age (RR ≥2 compared to ≥35 years) were at highest risk of delay. Other independent predictors were prematurity, maternal smoking during pregnancy, and being born in Western Australia (if Aboriginal) or another country in the Oceania region., Conclusion: The sub-populations at risk for delayed vaccination we have identified are likely generalisable to other high-income settings. Measures to improve their dose 1 timeliness, particularly for children with older siblings, are likely to have significant flow-on benefits for timeliness of later doses., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background: Despite recommendations that older adults receive acellular pertussis vaccines, data on direct effectiveness in adults aged over 50 years are sparse., Methods: A case-control study nested within an adult cohort. Cases were identified from linked pertussis notifications and each matched to 3 controls on age, sex, and cohort recruitment date. Cases and controls were invited to complete a questionnaire, with verification of vaccination status by their primary care provider. Vaccine effectiveness (VE) was estimated by conditional logistic regression, with adjustment for reported contact with children and area of residence., Results: Of 1112 notified cases in the cohort, we had complete data for 333 cases and 506 controls. Among 172 PCR-diagnosed cases (mean age, 61 years), 11.2% versus 19.5% of controls had provider-verified pertussis vaccination, on average, 3.2 years earlier. Adjusted VE against PCR-diagnosed pertussis was 52% (95% CI, 15-73%), nonsignificantly higher if vaccinated within 2 years (63%; -5-87%). Adjusted VE was similar in adults born before 1950, presumed primed by natural infection (51%; -8-77%) versus those born 1950 or later who may have received whole-cell pertussis vaccine (53%; -11-80%) (P-heterogeneity = 0.9). Among 156 cases identified by single-point serology, adjusted VE was -55% (-177-13%)., Conclusions: We found modest protection against PCR-confirmed pertussis among older adults (mean age, 61 years; range, 46-81 years) within 5 years after acellular vaccine. The most likely explanation for the markedly divergent VE estimate from cases identified by single-titer serology is misclassification arising from limited diagnostic specificity in our setting., (© The Author(s) 2019. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Background: Influenza attack rates in closed population settings, such as residential aged care facilities (RACFs), can be more than 50% during annual epidemics. Uncertainty about the effectiveness of neuraminidase inhibitors (NAIs) as prophylaxis for influenza outbreaks has led to variations in their use in RACFs in New South Wales (NSW), Australia., Objectives: To examine the use of prophylactic NAIs by NSW RACFs for residents during influenza outbreaks in the 2015 influenza season., Methods: A prospective cohort study of influenza outbreaks reported to NSW Public Health Units from 1 June 2015 - 31 October 2015., Results: Eighty-eight RACFs reported influenza outbreaks; 86 were included in the study. Fifty-two RACFs used prophylactic NAIs; 34 did not. The median time to start NAI prophylaxis from the onset date of the first case was 8.5 days (range 2-23). The average proportion of residents within a facility that received prophylaxis was 51%percnt; (range 0.7-95)., Conclusion: Variations in the use of prophylactic NAIs exist across RACFs. Earlier initiation of NAI prophylaxis, improved resident coverage where appropriate and other practice changes are recommended for the management of influenza outbreaks in RACFs., Competing Interests: None declared.

Background: In 2018, an outbreak of leptospirosis was identified among raspberry workers from a mixed-berry farm in New South Wales, Australia. Initial testing had not revealed a cause, but eventually leptospirosis was detected via polymerase chain reaction (PCR). Further serological testing detected Leptospira borgpetersenii serovar Arborea, of which rodents are the predominant reservoir. Leptospirosis is rare in Australia, with outbreaks usually related to flooding. We conducted an investigation to identify risk factors for infection, to inform control measures., Methods: Cases were detected through laboratory notifications, hospital-based syndromic surveillance, awareness-raising among farm employees and clinician alerts. Confirmed cases had a four-fold rise in antibody titre or single titre ≥400 on microscopic agglutination test, and a positive IgM. Probable cases had a positive Leptospira PCR or IgM, and possible cases had a clinically compatible illness. We conducted a case-control study among raspberry workers on the farm and compared reported exposures between cases and seronegative controls. We assessed environmental risks on-site and tested rodents for leptospirosis., Results: We identified 84 cases over a 5-month period (50 confirmed, 19 probable and 15 possible). Compared with controls, cases were less likely to wear gloves and more recently employed. Cases also more commonly reported always having scratched hands, likely from the thorns on raspberry plants. We observed evidence of rodent activity around raspberry plants and three of thirteen trapped mice tested positive for Leptospira Arborea. Control measures included enhanced glove use, doxycycline prophylaxis and rodent control., Conclusions: This is the largest known outbreak of leptospirosis in Australia. Workers were likely exposed through scratches inflicted during harvesting, which became contaminated with environmental leptospires from mice. Leptospirosis should be considered an occupational risk for raspberry workers, requiring protective measures. Chemoprophylaxis may assist in controlling outbreaks. PCR assists in the early diagnosis and detection of leptospirosis and should be included in surveillance case definitions., (© 2019 Blackwell Verlag GmbH.)

Aim: To describe the epidemiology of lymphogranuloma venereum (LGV) in New South Wales (NSW) from 2006 to 2015., Methods: LGV notification data between 2006 and 2015 from New South Wales were analysed to describe time trends in counts and rates by gender, age group and area of residence, as well as anatomical sites of infection. A positivity ratio was calculated using the number of LGV notifications per 100 anorectal chlamydia notifications per year. Data linkage was used to ascertain the proportion of LGV cases that were co-infected with HIV., Results: There were 208 notifications of LGV in NSW from 2006 to 2015; all were among men, with a median age of 42 years, and half were residents of inner-city Sydney. Annual notifications peaked at 57 (1.6 per 100,000 males) in 2010, declined to 16 (0.4 per 100,000 males) in 2014, and then increased to 34 (0.9 per 100,000 males) in 2015. Just under half (47.4%) of LGV cases were determined to be co-infected with HIV., Conclusion: The number of LGV notifications each year has not returned to the low levels seen prior to the peak in 2010. Continued public health surveillance is important for the management and control of LGV., (© Commonwealth of Australia CC BY-NC-ND.)

Background: Rotavirus vaccine has been funded for infants under the Australian National Immunisation Program since 2007, with Rotarix vaccine used in New South Wales, Australia, from that time. In 2017, New South Wales experienced a large outbreak of rotavirus gastroenteritis. We examined epidemiology, genotypic profiles, and vaccine effectiveness (VE) among cases., Methods: Laboratory-confirmed cases of rotavirus notified in New South Wales between January 1, 2010 and December 31, 2017 were analyzed. VE was estimated in children via a case-control analysis. Specimens from a sample of hospitalized case patients were genotyped and analyzed., Results: In 2017, 2319 rotavirus cases were reported, representing a 3.1-fold increase on the 2016 notification rate. The highest rate was among children aged <2 years. For notified cases in 2017, 2-dose VE estimates were 88.4%, 83.7%, and 78.7% in those aged 6 to 11 months, 1 to 3 years, and 4 to 9 years, respectively. VE was significantly reduced from 89.5% within 1 year of vaccination to 77.0% at 5 to 10 years postvaccination. Equinelike G3P[8] (48%) and G8P[8] (23%) were identified as the most common genotypes in case patients aged ≥6 months., Conclusions: Rotarix is highly effective at preventing laboratory-confirmed rotavirus in Australia, especially in infants aged 6 to 11 months. Reduced VE in older age groups and over time suggests waning protection, possibly related to the absence of subclinical immune boosting from continuously circulating virus. G8 genotypes have not been common in Australia, and their emergence, along with equinelike G3P[8], may be related to vaccine-induced selective pressure; however, further strain-specific VE studies are needed., Competing Interests: POTENTIAL CONFLICT OF INTEREST: Dr Bines is director of the Australian Rotavirus Surveillance Program, which receives funding to support the program from Commonwealth Serum Laboratories and GlaxoSmithKline (ID116120) as well as the Australian Government Department of Health (RFQ1-2015 Australian Rotavirus Surveillance Program); the other authors have indicated they have no potential conflicts of interest to disclose., (Copyright © 2019 by the American Academy of Pediatrics.)

In January 2015, a significant cold chain breach on a postnatal ward in a tertiary hospital in Sydney, Australia was noted to have been occurring since August 2013. Surveillance, amongst the 1178 mothers and 1178 babies affected, for vaccine-preventable diseases (VPDs) and adverse events following immunisation (AEFIs) using linkage with a notifiable diseases database was subsequently undertaken; no directly related instances of VPDs or AEFIs were detected. We evaluate this novel systematic surveillance method which has not been previously reported to determine whether it is effective in determining the impact of cold chain breaches on an individual and population level. The recommendation for revaccination of the affected mothers and subsequent surveillance was resource-intensive and future studies related to such incidents should focus on detailing the resources used to allow the costs versus benefits of such systematic surveillance to be determined., (Crown Copyright © 2019. Published by Elsevier Ltd. All rights reserved.)

Objective: Vaccinations in Australia are reportable to the Australian Immunisation Register (AIR). Following major immunisation policy initiatives, the New South Wales (NSW) Public Health Network undertook an audit to estimate true immunisation coverage of NSW children at one year of age, and explore reasons associated with under-reporting., Methods: Cross-sectional survey examining AIR immunisation records of a stratified random sample of 491 NSW children aged 12≤15 months at 30 September 2017 who were >30 days overdue for immunisation. Survey data were analysed using population weights., Results: Estimated true coverage of fully vaccinated one-year-old children in NSW is 96.2% (CI:95.9-96.4), 2.1% higher than AIR reported coverage of 94.1%. Of the children reported as overdue on AIR, 34.9% (CI:30.9-38.9) were actually fully vaccinated. No significant association was found between under-reporting and socioeconomic status, rurality or reported local coverage level. Data errors in AIR uploading (at provider level) and duplicate records contributed to incorrect AIR coverage recording., Conclusions: Despite incentives to record childhood vaccinations on AIR, under-reporting continues to be an important contributor to underestimation of true coverage in NSW. Implications for public health: More reliable transmission of encounters to AIR at provider level and removal of duplicates would improve accuracy of reported coverage., (© 2019 The Authors.)

Locally acquired hepatitis A infection is re-emerging in Australia owing to person-to-person outbreaks among men who have sex with men and imported frozen produce. This paper describes a multi-state foodborne outbreak in the first half of 2018. Enhanced human epidemiological investigation including a case-control study, as well as microbial surveillance and trace-back investigations concluded that the outbreak was caused by consumption of imported frozen pomegranate arils. A total of 30 cases of hepatitis A infection, genotype IB with identical sequences met the outbreak case definition, including 27 primary cases and three secondary cases. Twenty-five (83%) of the cases were hospitalised for their illness and there was one death. Imported frozen pomegranate arils from Egypt were strongly implicated as the source of infection through case interviews (19 of 26 primary cases) as well as from a case-control study (adjusted odds ratio 43.4, 95% confidence interval 4.2-448.8, P = 0.002). Hepatitis A virus (HAV) was subsequently detected by polymerase chain reaction in two food samples of the frozen pomegranate aril product. This outbreak was detected and responded to promptly owing to routine genetic characterisation of HAVs from all hepatitis A infections in Australia as part of a national hepatitis A enhanced surveillance project. This is now the third outbreak of hepatitis A in Australia from imported frozen fruits. A re-assessment of the risk of these types of imported foods is strongly recommended.

In 2016, the Transplantation Society of Australia and New Zealand, with the support of the Australian Government Organ and Tissue authority, commissioned a literature review on the topic of infectious disease transmission from deceased donors to recipients of solid organ transplants. The purpose of this review was to synthesize evidence on transmission risks, diagnostic test characteristics, and recipient management to inform best-practice clinical guidelines. The final review, presented as a special supplement in Transplantation Direct, collates case reports of transmission events and other peer-reviewed literature, and summarizes current (as of June 2017) international guidelines on donor screening and recipient management. Of particular interest at the time of writing was how to maximize utilization of donors at increased risk for transmission of human immunodeficiency virus, hepatitis C virus, and hepatitis B virus, given the recent developments, including the availability of direct-acting antivirals for hepatitis C virus and improvements in donor screening technologies. The review also covers emerging risks associated with recent epidemics (eg, Zika virus) and the risk of transmission of nonendemic pathogens related to donor travel history or country of origin. Lastly, the implications for recipient consent of expanded utilization of donors at increased risk of blood-borne viral disease transmission are considered., Competing Interests: None of the authors have any conflicts of interest to declare in relation to this work.

Reported infant vaccination coverage at age 12 months in Australia is >90%. On-time coverage of the 2-4-6 month schedule and coverage in specific populations is rarely reported. We conducted a population-based cohort study of 1.9 million Australian births, 1996-2012, combining individual birth and perinatal records with immunisation records through probabilistic linkage. We assessed on-time coverage across 13 demographic and perinatal characteristics of diphtheria-tetanus-pertussis vaccines (DTP) defined as vaccination 14 days prior to the scheduled due date, to 30 days afterwards. On-time DTP vaccination coverage in non-Aboriginal infants was 88.1% for the 2-month dose, 82.0% for 4-month dose, and 76.7% for 6-month dose; 3-dose coverage was 91.3% when assessed at 12 months. On-time DTP coverage for Aboriginal infants was 77.0%, 66.5%, and 61.0% for the 2-4-6 month dose; 3-dose coverage at 12 months was 79.3%. Appreciable differences in on-time coverage were observed across population subgroups. On-time coverage in non-Aboriginal infants born to mothers with ≥3 previous pregnancies was 62.5% for the 6-month dose (47.9% for Aboriginal infants); up to 23.5 percentage points lower than for first-borns. Infants born to mothers who smoked during pregnancy had coverage 8.7-10.3 percentage points lower than infants born to non-smoking mothers for the 4- and 6-month dose. A linear relationship was apparent between increasing socio-economic disadvantage and decreasing on-time coverage. On-time coverage of the 2-4-6 month schedule is only 50-60% across specific population subgroups representing a significant avoidable public health risk. Aboriginal infants, multiparous mothers, and those who are socio-economically disadvantaged are key groups most likely to benefit from targeted programs addressing vaccine timeliness., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

In 2016, the live attenuated zoster vaccine (Zostavax, Merck and Co, USA) was introduced into the Australian National Immunisation Program for people aged 70 years who are not significantly immunocompromised. We report the administration of Zostavax in an immunocompromised patient with chronic lymphocytic leukaemia and no evidence of primary varicella zoster virus (VZV) infection. The patient presented with a bilateral vesicular facial rash 22 days after receiving Zostavax and was initially managed as an outpatient with oral acyclovir. He re-presented three days later and was diagnosed with disseminated VZV infection complicated by meningoencephalitis. The patient died following cardiac arrest on day 10 of hospitalisation. This unfortunate case highlights the challenge of safely implementing a high titre live vaccine in a population where contraindications are prevalent. The non-live recombinant herpes zoster subunit vaccine (Shingrix, GSK) may provide a safe and effective option to protect immunocompromised patients from shingles and post-herpetic neuralgia., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Objectives: To assess vaccination coverage and timeliness among Indigenous and non-Indigenous children in New South Wales and the rest of Australia, with a particular focus on changes in the vaccination coverage gaps after the introduction of the Aboriginal Immunisation Healthcare Worker (AIHCW) Program in NSW in 2012., Design: Cross-sectional analysis of Australian Immunisation Register data (2008-2016)., Main Outcome Measures: Annual estimates of full vaccination coverage at 9, 15 and 51 months of age for Indigenous and non-Indigenous children in NSW and the rest of Australia; differences in coverage between Indigenous and non-Indigenous children at each milestone., Results: The proportion of Indigenous and non-Indigenous children classified as fully vaccinated at 9, 15, and 51 months increased significantly in both NSW and the rest of Australia after the introduction of the AIHCW Program. The mean annual difference in full vaccination coverage between Indigenous and non-Indigenous children in NSW aged 9 months declined from 6.6 (95% CI, 5.2-8.0) during 2008-2011 to 3.7 percentage points (95% CI, 2.5-4.8) during 2012-2016; for those aged 15 months it declined from 4.6 (95% CI, 3.1-6.0) to 2.2 percentage points (95% CI, 1.0-3.4), and for those aged 51 months it declined from 8.5 (95% CI, 7.2-9.8) to 0.6 percentage points (95% CI, -0.6 to 1.8). Reductions in the differences in coverage were not as marked in the rest of Australia. In 2016, there was no statistically significant difference in coverage at any of the three milestones in NSW: at 9 months the difference was 1.6 percentage points (95% CI, -1.0 to 4.1); at 15 months, 0.4 percentage points (95% CI, -2.2 to 2.9); and at 51 months, -1.8 percentage points (95% CI, -4.4 to 0.8)., Conclusion: Our findings suggest that a dedicated program can help overcome barriers to timely vaccination and significantly improve timely vaccination rates in Indigenous Australian children.

Background: Infants are at the highest risk of severe complications - including death - as a result of pertussis infection. Controlling pertussis in this group has been challenging, particularly in those too young to be vaccinated. Following revised national recommendations in March 2015, the state of New South Wales, Australia, introduced a funded maternal vaccination campaign at 28 - 32 weeks of gestation using a 3-component tetanus-diphtheria-acellular pertussis vaccine (dTpa; Boostrix, GSK). This study aimed to assess the effectiveness of maternal vaccination and add to the growing body of evidence for this strategy., Methods: A 1:1 matched case-control study was conducted between 16 August 2015 and 17 August 2016. Cases were laboratory or doctor notified, laboratory confirmed (nucleic acid testing or culture) and aged <6 months at onset. Each control infant was randomly selected from public hospital births in the same geographical area in the period up to 3 days before and after the case's birthdate. Odds ratios (OR) were calculated using conditional logistic regression. Vaccine effectiveness (VE) was calculated as 1 - OR., Findings: In total, 117 cases and 117 controls were recruited. The overall VE estimate was non-significantly protective for infants <6 months old (VE 39%, 95% CI -12 to 66%). Higher VE was observed for infants <3 months old (VE 69%, 95% CI 13-89%) and against hospitalisation (VE 94%, 95% CI 59-99%)., Interpretation: Maternal pertussis vaccination with a 3-component acellular vaccine was found to be highly effective at preventing severe disease in infants, but was less effective at preventing disease which did not require hospitalisation. The overall VE reported in this study was lower than in prior studies and suggests that maternal vaccination, while an effective strategy at preventing severe pertussis, is less effective at protecting against infection or mild disease., (Copyright © 2018. Published by Elsevier Ltd.)

The city of Sydney, Australia, experienced a persistent outbreak of Legionella pneumophila serogroup 1 (Lp1) pneumonia in 2016. To elucidate the source and guide public health actions, the genomes of clinical and environmental Lp1 isolates recovered over 7 weeks were examined. A total of 48 isolates from human cases and cooling towers were sequenced and compared using single-nucleotide polymorphism (SNP)-based core-genome multilocus sequencing typing (MLST) and pangenome approaches. All three methods confirmed phylogenetic relatedness between isolates associated with outbreaks in the Central Business District (CBD) in March and May and those in suburb 1. These isolates were designated the "main cluster" and consisted of isolates from two patients from the CBD March outbreak, one patient and one tower isolate from suburb 1, and isolates from two cooling towers and three patients from the CBD May outbreak. All main cluster isolates were sequence type 211 (ST211), which previously has only been reported in Canada. Significantly, pangenome analysis identified mobile genetic elements containing a unique type IV A F-type secretion system (T4ASS), which was specific to the main cluster, and cocirculating clinical strains, suggesting a potential mechanism for increased fitness and persistence of the outbreak clone. Genome sequencing enabled linking of the geographically dispersed environmental sources of infection among the spatially and temporally coinciding cases of legionellosis in a highly populated urban setting. The discovery of a unique T4ASS emphasizes the role of genome recombination in the emergence of successful Lp1 clones. IMPORTANCE A new emerging clone has been responsible for a prolonged legionellosis outbreak in Sydney, Australia. The use of whole-genome sequencing linked two outbreaks thought to be unrelated and confirmed the outliers. These findings led to the resampling and subsequent identification of the source, guiding public health actions and bringing the outbreak to a close. Significantly, the outbreak clone was identified as sequence type 211 (ST211). Our study reports this ST in the Southern Hemisphere and presents a description of ST211 genomes from both clinical and environmental isolates. A unique mobile genetic element containing a type IV secretion system was identified in Lp1 ST211 isolates linked to the main cluster and Lp1 ST42 isolates that were cocirculating at the time of the outbreak., (© Crown copyright 2018.)

Aim: To describe the distribution of known risk factors for listeria infection, including co-existing conditions, among listeriosis notifications in NSW between 2010 and 2015., Methods: Data from all notifications of invasive listeriosis in NSW between 01 January 2010 and 31 December 2015 were extracted from the NSW Notifiable Conditions Information Management System (NCIMS). OzFoodNet Listeria Case Questionnaires for each notification were reviewed. Descriptive analyses of notification data were undertaken., Results: Between 2010 and 2015, there were 158 listeriosis notifications in NSW with an average of 26.3 notifications a year. Persons over 65 years represented 71.5% of all notifications. A total of 4.4% notifications were among pregnant women, while 79.1% and 64.6% were among persons with a condition and on treatment, respectively, known to supress the immune response or increase the risk of infection. Specifically, cancer patients and persons on cancer treatment (chemotherapy, radiotherapy) represented 31.0% and 13.9%, respectively, of all listeriosis notifications. Information on foods to avoid in preventing listeria from a healthcare worker prior to infection was received by 7.2% of notifications with a known risk condition and 5.9% of notifications on medication; 41.6% and 46.1% respectively had visited a hospital in the four weeks prior to notification., Conclusions: The prevalence of known risk factors for listeriosis among notified cases remains significant in NSW. Improved risk communication for this population, starting with information from healthcare professionals, may be beneficial in reducing the burden of listeriosis in known vulnerable groups who have regular contact with the health system., (This work is copyright. You may download, display, print and reproduce the whole or part of this work in unaltered form for your own personal use or, if you are part of an organisation, for internal use within your organisation, but only if you or your organisation do not use the reproduction for any commercial purpose and retain this copyright notice and all disclaimer notices as part of that reproduction. Apart from rights to use as permitted by the Copyright Act 1968 or allowed by this copyright notice, all other rights are reserved and you are not allowed to reproduce the whole or any part of this work in any way (electronic or otherwise) without first being given the specific written permission from the Commonwealth to do so. Requests and inquiries concerning reproduction and rights are to be sent to the Online, Services and External Relations Branch, Department of Health, GPO Box 9848, Canberra ACT 2601, or by email to copyright@health.gov.au.)

Objectives: To examine antimicrobial susceptibility patterns and predictors of resistance among Shigella isolates in New South Wales (NSW), Australia during 2013-14 with emphasis on azithromycin., Methods: Cross-sectional analysis of all shigellosis cases (160) notified to public health authorities in NSW, Australia was performed., Results: Among 160 Shigella isolates tested, 139 (86.9%) were susceptible to azithromycin, 104 (65.0%) to ciprofloxacin and 38 (23.7%) to co-trimoxazole. Ciprofloxacin resistance was 1.9 times more common in infections acquired in Australia compared with those acquired overseas, while azithromycin resistance was 8.5 times more common in males., Conclusions: We recommend ongoing reconsideration of guidelines for the treatment of shigellosis based on emerging resistance patterns. First-line therapy may need to be reconsidered based on local resistance rates due to common resistance to co-trimoxazole and ciprofloxacin. We recommend culture and susceptibility testing for suspected and proven shigellosis. Azithromycin susceptibility breakpoints for Shigella species may need to be species specific., (© The Author 2017. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Introduction: Several countries have developed national immunisation registers, but only the Nordic countries have linked their registers to other health data in order to comprehensively evaluate the `real world' effectiveness of vaccines. Nordic countries can link datasets deterministically using the national person identifier, but most countries, including Australia, don't have such an identifier to enable this type of linkage., Objectives: To describe the process for assembling a linked study cohort that will enable the conduct of population-based studies related to immunisation and immunisation policy., Methods: National death and immunisation databases along with state health data (notifications of vaccine preventable diseases, perinatal data, hospital admissions and emergency department presentations) up until December 2013 were probabilistically linked (using demographic details) for children born between 1996 and 2012 in two states: Western Australia and New South Wales (42% of Australia's population, combined)., Results: After exclusions there were 1.95 million children in the study cohort (live born children with both a birth and perinatal record which represents 97.5% of all live births in the state perinatal data collections - our source population) and 18.0 million person years of follow up (mean: 9.2 years per child). The characteristics of children in the cohort were generally similar to those only included in state perinatal databases and outcome measures were in keeping with expected figures from unlinked data sources. However, the lack of a dynamic national population register meant immigrants could not be included., Conclusions: We have been able to develop a similarly comprehensive system to the Nordic countries based on probabilistic linkage methods. Our experience should provide encouragement to other countries with national immunisation registers looking to establish similar systems., Competing Interests: Statement on conflicts of interest: None declared.

In November 2014, New South Wales Health was notified of a cluster of respiratory illness in a veterinary school. Active case finding identified another case at a local equine stud. All cases had exposure to the equine fetal membranes of Mare A. This tissue subsequently tested positive for Chlamydia psittaci using quantitative real-time polymerase chain reaction. We conducted a cohort study of the university and stud farm staff to determine risk factors for disease. Nine people were exposed to the fetal membranes of Mare A. Of these, five cases of psittacosis were identified. Two required hospital admission. Contact with birds was not associated with illness (RR = 0.5, 95% CI = 0.09-2.73). People who had direct contact with the abnormal fetal membranes were more likely to develop disease (RR = 11.77, 95% CI = 1.02-∞). The emergence of an association between horse exposure and C. psittaci infection has important implications for the prevention and control of psittacosis. Article summary line : Investigation of an outbreak of psittacosis in a rural veterinary school demonstrates novel source of infection for psittacosis through exposure to abnormal equine fetal membranes.

Background: Amidst an Ebola virus disease (EVD) epidemic of unprecedented magnitude in west Africa, concerns about the risk of importing EVD led to the introduction of programs for the screening and monitoring of travellers in a number of countries, including Australia. Emerging reports indicate that these programs are feasible to implement, however rigorous evaluations are not yet available. We aimed to evaluate the program of screening and monitoring travellers in New South Wales., Methods: We conducted a mixed methods study to evaluate the program of screening and monitoring travellers in New South Wales. We extracted quantitative data from the Notifiable Conditions Information Management System database and obtained qualitative data from two separate surveys of public health staff and arrivals, conducted by phone., Results: Between 1 October 2014 and 13 April 2015, public health staff assessed a total of 122 out of 123 travellers. Six people (5%) developed symptoms compatible with EVD and required further assessment. None developed EVD. Aid workers required lower levels of support compared to other travellers. Many travellers experienced stigmatisation. Public health staff were successful in supporting travellers to recognise and manage symptoms., Conclusion: We recommend that programs for monitoring travellers should be tailored to the needs of different populations and include specific strategies to remediate stigmatisation.

Introduction: In countries where measles is rare, health-care-setting transmissions remain problematic. Australia experienced its largest measles outbreak in 15 years in 2012 with 199 cases reported nationally; 170 cases occurred in the state of New South Wales (NSW) with symptom onset between 7 April and 29 November 2012., Methods: A descriptive study was conducted using measles case data obtained from metropolitan Sydney local health districts in NSW in 2012. Characteristics of measles source and secondary cases were described. Details of health-care presentations resulting and not resulting in measles transmission were also analysed., Results: There were 168 confirmed and two probable cases resulting in 405 documented health-care presentations. Thirty-four secondary cases acquired in health-care settings were identified, including 29 cases resulting from 14 source cases and 5 cases whose source could not be identified. Health-care-acquired cases accounted for 20% of all cases in this outbreak. Source cases were more likely to be of Pacific Islander descent ( P  = 0.009) and to have had more presentations before diagnosis ( P  = 0.012) compared to other cases. The percentage of presentations to emergency departments was higher for presentations that resulted in transmission compared to those that did not (71.4% and 37.6%, respectively, P  = 0.028). There were no significant differences between transmission and non-transmission presentations with respect to presence of rash and infection control measures ( P  = 0.762 and P  = 0.221, respectively), although the power to detect these differences was limited. Rash was reported at 66% of the presentations., Conclusion: Development of and adherence to protocols for the management of patients presenting to hospitals with fever and rash will minimize secondary transmission of measles.

Introduction: In response to a significant increase of measles cases and a high percentage of unvaccinated adolescents in New South Wales, Australia, a measles high school catch-up vaccination programme was implemented between August and December 2014. This study aimed to explore the factors affecting school-based supplementary immunization activities (SIAs) and to inform future SIA and routine school-based vaccination programme implementation and service provision., Methods: Focus group analysis was conducted among public health unit (PHU) staff responsible for implementing the SIA catch-up programme. Key areas discussed were pre-programme planning, implementation, resources, consent materials, media activity and future directions for school vaccination programme delivery. Sessions were audio recorded, transcribed verbatim and reviewed. Thematic analysis was conducted to identify the major themes., Results: Two independent focus groups with 32 participants were conducted in January 2015. Barriers to the SIA implementation included lead time, consent processes, interagency collaboration, access to the targeted cohort and the impact of introducing a SIA to an already demanding curriculum and school programme immunization schedule. A positive PHU school coordinator rapport and experience of PHU staff facilitated the implementation. Consideration of different approaches for pre-clinic vaccination status checks, student involvement in the vaccination decision, online consent, workforce sharing between health districts and effective programme planning time were identified for improving future SIA implementation., Conclusion: Although many barriers to school programme implementation have been identified in this study, with adequate resourcing and lead time, SIAs implemented via a routine school vaccination programme are an appropriate model to target adolescents.