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A literature review was conducted to identify evidence of cases and outbreaks of vaccine-preventable diseases (VPDs) that have been reported from on board ships and the methods applied on board for prevention and control, worldwide, in 1990 to April 2019. Moreover, evidence from seroprevalence studies for the same diseases were also included. The literature review was conducted according to Preferred Reporting Items for Systematic reviews (PRISMA) guidelines. A total of 1795 cases (115 outbreaks, 7 case reports) were identified, the majority were among crew (1466/1795, 81.7%) and were varicella cases (1497, 83.4%). The origin of crew cases was from sub-tropical countries in many reports. Measles (40 cases, 69% among crew), rubella (47, 88.7%), herpes zoster (9, 69.2%) and varicella cases (1316, 87.9%) were more frequent among crew. Mumps cases were equal among passengers and crew (22/22). Hepatitis A (73/92, 70.3%), meningococcal meningitis (16/29, 44.8%), and pertussis (9/9) were more frequent among passengers. Two outbreaks resulted in 262 secondary measles cases on land. Review results were used to draft a new chapter for prevention and control of VPDs in the European Manual for Hygiene Standards and Communicable Disease Surveillance on Passenger Ships. Despite past and current evidence for cross-border VPD transmission and maritime occupational risks, documented pre-employment examination of immune status, vaccination of seafarers, and travel advice to passengers are not yet regulated.

Background: Varicella‐zoster virus (VZV) pretransplant immunization rates, exposures, and posttransplant disease are poorly characterized among pediatric solid organ transplant (SOT) recipients in the two‐dose varicella vaccine era. Methods: A retrospective analysis of the electronic health records among children <18 years old who received SOT from January 1, 2011 through December 31, 2021, was performed at a single center to assess for missed pretransplant varicella vaccination opportunities, characterize VZV exposures, and describe posttransplant disease. Results: Among 525 children, 444 were ≥6 months old (m.o.) at SOT with a documented VZV vaccine status. Eighty‐five (19%) did not receive VZV Dose One; 30 out of 85 (35%) could have been immunized. Infants 6–11 m.o. accounted for 14 out of 30 (47%) missed opportunities. Among children ≥12 m.o. with documented Dose Two status (n = 383), 72 had missed vaccination opportunities; 57 out of 72 (79%) were children 1–4 years old. Most children had unclassifiable pre‐SOT serostatus as varicella serology was either not obtained/documented (n = 171) or the possibility of passive antibodies was not excluded (n = 137). Of those with classified serology (n = 188), 69 were seroimmune. Forty‐seven of 525 (9%) children had recorded VZV exposures; two developed varicella—neither had documented pre‐SOT seroimmunity nor had received post‐exposure prophylaxis. Nine additional children had medically attended disease: four primary varicella and five zoster. Of the 11 cases, 10 had cutaneous lesions without invasive disease; one had multi‐dermatomal zoster with transaminitis. Seven (64%) received treatment exclusively outpatient. Conclusions: VZV exposure and disease still occur. Optimizing immunization among eligible candidates and ensuring patients have a defined VZV serostatus pretransplantation remain goals of care. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate seroepidemiology of varicella in Wuxi, China, after two doses of immunization of varicella vaccine (VarV) for better control of varicella transmission. Participants were selected randomly by multistage stratified sampling. The positive rate of antibody and geometric antibody titer (GMC) was determined with enzyme-linked immunosorbent assays. Logistic and linear regressions were used to analyze the correlations between antibody seropositivity, GMCs, and corresponding factors. Serum samples (n = 697) were obtained from healthy children

Immunisation against herpes zoster is recommended for adults aged ≥ 50 years. Two vaccines, a live attenuated (ZVL, Zostavax®) and an adjuvant recombinant subunit (HZ/su, Shingrix®), are available in Australia. Immunisation guidelines are shifting their recommendations towards HZ/su because of higher efficacy in preventing herpes zoster and associated complications. However, there are limited post-marketing data comparing the safety profiles of these vaccines. Data from SmartVax, an active surveillance system for monitoring adverse events following immunisation (AEFIs) utilised by > 450 clinics throughout Australia, were analysed. Data from patients aged ≥ 50 years, who received ZVL or HZ/su, from 1 June 2021 to 31 May 2022, at clinics that utilised SmartVax were included. The proportion of records where patients who reported any, local, and systemic AEFIs after receiving ZVL or HZ/su were compared using multivariable logistic regression models. Data from 10,392 immunisation records (n = 8341 ZVL; n = 2051 HZ/su) were included. The proportion of AEFIs reported was higher with HZ/su (41.9 % [any], 33.8 % [local], 25.2 % [systemic]) than with ZVL (8.7 % [any], 6.2 % [local], 3.5 % [systemic]). After controlling for demographic variables, HZ/su presented a 6-fold increase in the odds (OR 6.44; 95 %CI: 5.57–7.46) of a reported AEFI compared to ZVL. Only 59 (0.6 %) of vaccinations lead to medical attention being sought due to an AEFI. While rates of AEFIs was higher with HZ/su than ZVL, most AEFIs were mild and did not require medical attention. Our findings support the change in vaccine recommendations and the use of HZ/su in immunisation programs. [ABSTRACT FROM AUTHOR]

Background: To analyze the epidemiological characteristics of varicella epidemics in Chongqing Municipality from 2014 to 2021, and to provide a scientific basis for the formulation of varicella prevention and control measures. Methods: Data on the incidence of varicella outbreaks and vaccination data in Chongqing from 2014 to 2021 were collected through the China Disease Control and Prevention Information System and statistically analyzed using descriptive epidemiological methods. Results: From 2014 to 2021, 213,715 cases of varicella were reported in Chongqing Municipality, with an average annual incidence rate of 86.26/100,000, with a statistically significant difference (χ2 = 24,972.069, P < 0.001); varicella incidence is seasonal, with peaks in May/June and October/December each year, presenting a "double-peak distribution". The average annual incidence rate of varicella in municipal districts was 90.74/100,000, which was higher than that of counties 69.62/100,000 and autonomous counties 84.04/100,000; the average annual incidence rate of varicella in males was 89.37/100,000, and in females, 82.22/100,000, with the difference not being statistically significant; the age of onset of the disease was mainly in the group of people under 15 years of age, with a total of 190,021 cases reported (88.9%), with 5-9 years old (35.7%) as the high incidence age group. The incidence occupation was dominated by students in 133,733 cases (62.6%). Conclusion: The overall varicella epidemic in Chongqing is on the rise, and has obvious seasonal, regional and population distribution characteristics. The prevention and control of varicella epidemic should be strengthened, the publicity of varicella vaccine should be increased, and it is recommended that varicella vaccine should be included in the national immunization program. [ABSTRACT FROM AUTHOR]

The use of live attenuated vaccines in patients with immunosuppressive agents is contraindicated in package inserts and guidelines in Japan and other countries. However, patients receiving immunosuppressants have a high risk of infectious disease becoming severe, and the necessity to prevent infectious disease is high. To date, 2,091 vaccinations have been reported in 25 reports of live attenuated vaccines in people receiving immunosuppressants. Twenty-three patients (1.1%) became infected with the virus strain used in the vaccine, which was varicella virus in 21 patients. No reports have described life-threatening complications. A prospective study at the National Center for Child Health and Development conducted under certain immunological conditions (CD4 cell count ≥ 500/mm3, stimulation index of lymphocyte blast transformation by phytohemagglutinin (PHA) ≥ 101.6, serum immunoglobulin G ≥ 300 mg/dL) confirmed the serological effectiveness and safety. The evidence suggests that live attenuated vaccines can be used even in combination with immunosuppressants. Further evidence must be gathered and immunological criteria investigated to determine the conditions for safe use. Depending on the results of these investigations, the wording in package inserts and guidelines may need to be revised. [ABSTRACT FROM AUTHOR]

Objective To analyze the epidemiological characteristics of varicella in Guiyang city and to provide scientific basis for formulating appropriate prevention and control measures and immunization strategies for varicella. Methods The data of varicella incidence, resident population, and vaccination in Guiyang were collected through China Disease Prevention and Control Information Management system and Guizhou Immunization Planning Information Management system. Descriptive epidemiological methods were used to analyze the epidemiological characteristics and vaccination of varicella vaccine in Guiyang City from 2010 to 2022. Results A total of 32 405 varicella cases were reported in Guiyang city from 2010 to 2022, with an average annual incidence of 54.39/100 000. The incidence of varicella in people under 15 years old was 75.46%. The incidence of varicella was relatively stable from 2011 to 2016 and then increased in 2017 and 2021, while the proportion of female cases in the total population showed an upward trend (S=56.000, τ=0.718, P < 0.001). The incidence of 0 to < 3 years old showed a downward trend, increased continuously in 3 to < 5 years old, reached a peak in 5 to < 6 years old, and then decreased gradually. The incidence percentage of the whole population aged 10 to < 15 and 15 to < 20 years old showed an increasing trend. The two peak incidence rates were from November to January and from May to July, respectively, and the incidence rates in Guanshan Lake district and Baiyun district were higher than those in other districts (cities and counties). The incidence of varicella in Guiyang city over the years was negatively correlated with the number of two doses of varicella vaccine in the same year (r=-0.610, P=0.027). Conclusion The incidence of varicella in Guiyang city shows a downward trend, with obvious seasonal, regional, and population characteristics, and the incidence is mainly among students under 15 years old. The better the second dose of varicella vaccine is, the lower the incidence is, so it is necessary to strengthen the inspection of varicella vaccination in enrollment. On the other hand, considering the increasing incidence of people aged 10 to < 15 and 15 to < 20 years old in Guiyang, it is necessary to strengthen the publicity and varicella vaccination for students of all ages. [ABSTRACT FROM AUTHOR]

To evaluate the impact of a two-dose VarV program on varicella incidence among the whole population, considering the influence of public health and social measures (PHSMs), we extracted surveillance data on varicella cases during 2013–2022 in Minhang, Shanghai. Then, we estimated the incidence trend of varicella through interrupted time-series analyses and quantified the impact of the immunization program and PHSMs using Serfling regression. We also explored the associations between PHSMs and varicella cases. The implementation of the two-dose VarV strategy was followed by a significant decrease in varicella incidence (−1.84% per month). After one year of the program, varicella incidence was estimated at a 45.25% reduction, which was higher in children (59.12% and 54.09%) than in adults (19.49%). The decrease attributed to PHSMs was 31.26% during 2020–2022, and school closing was identified as the most relevant PHSM (b = −8.03 cases, r = −0.67 with a 1-week lag). These findings indicate that the two-dose immunization program has more effectively reduced the varicella incidence compared with the one-dose vaccine, and interventions like school closings are also encouraged to serve as supplementary measures to prevent varicella epidemics. [ABSTRACT FROM AUTHOR]

The aim of this study was to analyze the seroprevalence of varicella in Italy and to evaluate the impact of varicella vaccination, which has been mandatory for newborns since 2017. The levels of VZV-specific IgG antibodies were determined by the ELISA method in residual serum samples obtained from subjects aged between 6 and 64 years and residing in 13 Italian regions. Overall, 3746 serum samples were collected in the years 2019 and 2020. The overall seroprevalence was 91.6% (89.9% in males and 93.3% in females; p = 0.0002). Seroprevalence showed an increasing trend (p < 0.0001) starting in the younger age groups: 6–9 years: 84.1%; 10–14 years: 88.7%; 15–19 years: 89.3%; 20–39 years: 93.1% and >40 years: 97.0%. The seroprevalence data obtained in the present study were compared with those relating to previous sero-epidemiological surveys conducted, respectively, in the years 1996–1997, 2003–2004 and 2013–2014, taking into consideration only data from regions monitored in all surveillance campaigns. The comparison highlighted for the period 2019–2020 showed significantly higher values in the age groups 6–9 (p < 0.001), 10–14 (p = 0.018) and 15–19 years (p = 0.035), while in adults, the trend did not change over time (ns). These results highlight the positive impact of varicella vaccination in Italy. [ABSTRACT FROM AUTHOR]

BackgroundVaricella zoster virus (VZV) causes both varicella (chickenpox) and herpes zoster (shingles) and is associated with significant global morbidity. Most epidemiological data on VZV come from high-income countries, and to date there are limited data on the burden of VZV in Africa.MethodsWe assessed the seroprevalence of VZV antibodies among children in the Democratic Republic of Congo in collaboration with the 2013-2014 Demographic and Health Survey. Dried blood spot samples collected from children 6-59 months of age were run on Dynex™ Technologies Multiplier FLEX® chemiluminescent immunoassay platform to assess serologic response. Multivariate logistic regression was then used to determine risk factors for VZV seropositivity.ResultsSerologic and survey data were matched for 7,195 children 6-59 months of age, among whom 8% were positive and 2% indeterminate for VZV antibodies in weighted analyses. In multivariate analyses, the odds of seropositivity increased with increasing age, increasing socioeconomic status, mother's education level, rural residence, and province (South Kivu, North Kivu, Bandundu, Bas Congo had the highest odds of a positive test result compared with Kinshasa).ConclusionOur data suggest that VZV is circulating in DRC, and seropositivity is low among children 6-59 months. Seropositivity increased with age and varied by other sociodemographic factors, such as geographic location. This study provides the first nationally representative estimates of VZV infection among children in the DRC.

We summarize studies of varicella vaccine's effectiveness for prevention of varicella and lessons learned during the first 25 years of the varicella vaccination program in the United States. One dose of varicella vaccine provided moderate protection (82%-85%) against varicella of any severity and high protection (100%) against severe varicella, with some waning of protection over time. The 1-dose program (1995-2006) had a substantial impact on the incidence both of varicella and of severe outcomes (71%-90% decrease) although it did not prevent low-level community transmission and some outbreaks continued to occur in highly vaccinated populations. Two doses of varicella vaccine improved the vaccine's effectiveness by at least 10% against varicella of any severity, with further declines in the incidence both of varicella and of severe outcomes as well as in both number and size of outbreaks. There is no evidence for waning of the effectiveness of 2 doses of the vaccine. [ABSTRACT FROM AUTHOR]

Background: The varicella vaccine is excluded from the Chinese national immunisation programme but is included in the local expanded programme on immunisation (EPI) in the Suzhou Prefecture. This study investigated the epidemiological characteristics of the varicella cases during the implementation of different immunisation strategies in the Suzhou Prefecture, Jiangsu Province. Methods: In this study, we used descriptive statistics. Information on reported instances from 2012 to 2021 was first retrieved. Data on varicella cases were collected from the China Information System for Disease Control and Prevention (CISDCP). Similarly, information on vaccinated children was obtained from the Jiangsu Province Vaccination Integrated Service Management Information System (JPVISMIS). The census data in this study was procured from the Suzhou Bureau of Statistics. Results: From 2012 to 2021, a total of 118,031 cases of varicella were reported in Suzhou, and the average annual reported incidence was 91.35 per 100,000. The average yearly incidence after implementing the two-dose varicella vaccination decreased by 41.57% compared with the implementation of one dose. This study demonstrates two annual incidence peaks, a small peak between April and July and a prominent peak between October and January. It is also possible that this seasonal distribution is related to the geography of Suzhou. The average annual reported incidence between districts with a statistically significant difference (χ2 = 98.077, p < 0.05). The one-dose varicella vaccination coverage gradually increased from 55.34% in 2012 to 89.06% in 2021 and the two-dose varicella vaccination coverage gradually increased from 0.27% in 2012 to 82.17% in 2021. Conclusions: Administering the varicella vaccine in the local EPI has significantly decreased the incidence rate and the total number of cases. A two-dose vaccination schedule is still the best vaccination strategy for varicella vaccine effectiveness. [ABSTRACT FROM AUTHOR]

Background: Varicella–Zoster virus (VZV) infection in healthcare organizations, especially in intensive care units (ICU), having admitted immunocompromised patients, is of serious concern as well as poses threat to healthcare workers working in such critical areas. The present report defines the transmission and infection control measures initiated to curtail VZV infection spread in the trauma ICU of a tertiary care hospital of North India. Outbreak Report: At the infection outset, there were 12 patients admitted in ICU and 54 healthcare workers were posted to manage these critical patients. After confirmation of VZV infection, all susceptible patients as well as healthcare workers were quarantined and fresh intake of patients was restricted. Out of the total healthcare workers, 14 (25.92%) were found susceptible (as per protective VZV IgG titers) and were vaccinated. Of the 12 patients admitted in the ICU, six patients were discharged and sent home directly, four patients expired due to their critical disease state, one patient left against medical advice, and one patient remained admitted in ICU till the incubation period was over. Epidemiologically, line listing for index case reporting was done. The efficacy of control measures was re-evaluated to strengthen existing infection control practices and general measures viz. strict hand washing, adherence to aseptic protocols and intensification of environmental cleaning. Conclusions: Established varicella surveillance measures ensure VZV outbreaks are identified in a timely manner and control measures implemented to prevent further transmission. Also, vaccination policy among HCWs is the utmost requirement despite having huge financial implications.

Studies have shown an increased risk of febrile convulsions (FC) after first immunization with the quadrivalent measles-mumps-rubella-varicella vaccine (MMRV) compared to a first dose of measles-mumps-rubella vaccine (MMR) only or in combination with separately administered varicella vaccine (MMR + V). Therefore, it is recommended to give MMR + V at first dose and MMRV or MMR + V at second dose. Little is known on the risk of FC after MMRV at second dose, especially whether the risk depends on age, sex, history of FC or type of first dose vaccine. A retrospective cohort study using claims data from the German Pharmacoepidemiological Research database (GePaRD) was performed in children born between January 1st, 2004 and October 31st, 2015 who received two doses of MMRV, MMR + V or MMR. Cases were defined as hospitalization with a diagnosis of FC without neurological conditions coded as main discharge diagnosis. Unadjusted and adjusted odds ratios (OR) with 95% confidence intevals (CIs) were calculated to compare the risk of FC. Stratified analyses were performed to examine potential effect modification by age, sex, history of FC or type of first dose vaccine. In the first 30 days after second dose vaccination, 464 FCs were observed in a cohort of 528,639 children with a median age of 17 months. After adjustment for potential confounders, the adjusted OR for FC in the 30 days after vaccination was 1.25 (95% CI 0.67–2.30) for MMRV compared to MMR + V and 1.04 (0.82–1.32) for MMRV compared to MMR. History of FC was the most important risk factor with an OR of 36.26 (29.30–44.89). We found no effect modification by age, sex, history of FC, or type of first dose vaccine. Use of MMRV at second dose is not associated with an increased risk of FC compared to MMR + V or MMR, irrespective of age, sex, history of FC, or type of first dose vaccine. [ABSTRACT FROM AUTHOR]

Varicella-zoster virus (VZV) causes varicella as a primary infection and remains latent in the ganglia until it becomes reactivated to cause herpes zoster. Individuals with varicella develop adaptive humoral and cell-mediated immunity. Compromised cell-mediated immunity is thought to contribute to the development of herpes zoster. Recent evidence suggests that changes in the epidemiology of varicella have affected the epidemiology of herpes zoster. The incidence of herpes zoster is higher in older adults; thus, the herpes zoster vaccine is recommended for older adults. However, the incidence of herpes zoster is expected to rise among younger individuals; hence, vaccination with the varicella vaccine should also be considered in younger adults. In order to determine the need for vaccination in different populations, it is important to establish methods to accurately assess the activity of cell-mediated immunity and humoral immunity. [ABSTRACT FROM AUTHOR]

Background Despite the burden of varicella, there is no universal varicella vaccination (UVV) program in the United Kingdom (UK) due to concerns that it could increase herpes zoster (HZ) incidence. We assessed the cost-utility of a first-dose monovalent (varicella [V]) or quadrivalent (measles-mumps-rubella-varicella [MMRV]) followed by a second-dose MMRV UVV program. GSK and MSD varicella-containing vaccines (VCVs) were considered. Methods Dynamic transmission and cost-effectiveness models were adapted to the UK. Outcomes measured included varicella and HZ incidences and the incremental cost-utility ratio (ICURs) over a lifetime horizon. Payer and societal perspectives were evaluated. Results The impact of V-MMRV and MMRV-MMRV UVV programs on varicella incidence was comparable between both VCVs at equilibrium. HZ incidence increased by 1.6%–1.7% over 7 years after UVV start, regardless of the strategies, then decreased by >95% at equilibrium. ICURs ranged from £5665 (100 years) to £18 513 (20 years) per quality-adjusted life-year (QALY) gained with V-MMRV and from £9220 to £27 101 per QALY gained with MMRV-MMRV (payer perspective). MMRV-MMRV was cost-effective in the medium- and long-terms with GSK VCV and only cost-effective in the long term with MSD VCV at a £20 000 per QALY gained threshold. Without the exogenous boosting hypothesis, HZ incidence decreased through UVV implementation. ICURs were most sensitive to discount rates and MMRV price. Conclusions A 2-dose UVV was demonstrated to be a cost-effective alternative to no vaccination. With comparable effectiveness as MSD VCV at lower costs, GSK VCV may offer higher value for the money. [ABSTRACT FROM AUTHOR]

The aim of this study was to analyze the seroprevalence of varicella in Italy and to evaluate the impact of varicella vaccination, which has been mandatory for newborns since 2017. The levels of VZV-specific IgG antibodies were determined by the ELISA method in residual serum samples obtained from subjects aged between 6 and 64 years and residing in 13 Italian regions. Overall, 3746 serum samples were collected in the years 2019 and 2020. The overall seroprevalence was 91.6% (89.9% in males and 93.3% in females; p = 0.0002). Seroprevalence showed an increasing trend (p < 0.0001) starting in the younger age groups: 6–9 years: 84.1%; 10–14 years: 88.7%; 15–19 years: 89.3%; 20–39 years: 93.1% and >40 years: 97.0%. The seroprevalence data obtained in the present study were compared with those relating to previous sero-epidemiological surveys conducted, respectively, in the years 1996–1997, 2003–2004 and 2013–2014, taking into consideration only data from regions monitored in all surveillance campaigns. The comparison highlighted for the period 2019–2020 showed significantly higher values in the age groups 6–9 (p < 0.001), 10–14 (p = 0.018) and 15–19 years (p = 0.035), while in adults, the trend did not change over time (ns). These results highlight the positive impact of varicella vaccination in Italy.

Previous studies have found higher rates of varicella susceptibility among migrants from tropical regions. This study seeks to estimate the prevalence of varicella susceptibility in a cohort of newly arrived refugees and refugee claimants at a primary care clinic in Toronto and to compare patients' self-reported history of varicella infection with serologic test results. We conducted a retrospective chart review of 1888 refugee patients aged 13 years and older rostered at a specialized primary care clinic in Toronto from December 2011 to October 2017. Basic sociodemographic variables, self-reported varicella history, and varicella serologic results were examined. Based on serologic testing, 8.5% of individuals were varicella non-immune, with highest rates of varicella susceptibility among adolescents aged 13–19 years (13.5%). All adults over age 60 were varicella immune on serology (n = 56). A positive self-reported history of varicella infection was strongly predictive of varicella immunity on serology (PPV 96.8%; 95% CI: 95.2–97.9). A self-reported history of no prior varicella infection did not correlate reliably with serologic test results (NPV 15.8%; 95% CI: 13.3–18.0). A substantial proportion of patients (34.1%) were unsure of their varicella history. Identification and immunization of varicella susceptible refugee newcomers remains a health care priority. Self-reported history of varicella infection had mixed reliability as a predictor of varicella immunity. [ABSTRACT FROM AUTHOR]

It remains hesitant to include a two-dose varicella vaccine (VarV) in a national routine immunization program in China. We aimed to quantify the impact of the two-dose VarV on varicella incidence in Shanghai. We directly extracted the data of varicella cases and VarV doses in 2013–2020 in Shanghai, and then estimated the effects of two-dose VarV using a Serfling model. A two-dose VarV immunization program has been extensively implemented since October 2017 and become free since August 2018 in Shanghai. Before and after this program, varicella cases significantly declined in children (P < 0.01), whereas did not in adults aged >18 years (P = 0.22). Compared to the predicted number of varicella cases, actual number was significantly lower by 8% in 2018 and 28% in 2019. Among children aged 4–6 years, the reduction in varicella cases was largest. Moreover, there was a significant reduction in varicella cases throughout 2020 (P < 0.001), in which the decrease due to social distancing for the COVID-19 was 54%. A two-dose VarV immunization program may further reduce approximately one-third of varicella cases in Shanghai. Children <4 years and adults benefit less in this program, which warrants enhancing the immunization. [ABSTRACT FROM AUTHOR]