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Background: Migrants are not routinely screened for hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV) in the Netherlands. We estimated the prevalence and determined factors associated with HBV, HCV and/or HIV infections among undocumented migrants and uninsured legal residents. Methods: In this cross-sectional study, undocumented migrants and uninsured legal residents were recruited at a non governmental organization (NGO), healthcare facility in the Netherlands and were invited to be tested for hepatitis B surface antigen (HBsAg), anti-hepatitis B core antibodies (anti-HBcAb), HCV-RNA, and anti-HIV antibodies or HIV antigen at a local laboratory. Results: Of the 1376 patients invited, 784 (57%) participated. Participants originated from Africa (35%), Asia (30%) and North/South America (30%). 451/784 (58%) participants went to the laboratory for testing. Of participants 30% were HBV exposed (anti-HBcAb-positive), with 27% (n = 119/438, 95% CI 23.1% to 31.6%) having resolved HBV infection (HBsAg-negative) and 2.5% (n = 11/438, 95%CI 1.3% to 4.5%, 64% new infection) having chronic HBV infection (HBsAg-positive). Compared to HBV non-exposed, HBV exposed individuals were older (p = 0.034) and more often originated from Africa (p<0.001). Prevalence of chronic HCV infection (HCV-RNA-positive) was 0.7% (n = 3/435, 95%CI 0.1% to 2.0%, all new infections) and HIV infection 1.1% (n = 5/439, 95%CI 0.04% to 2.6%, 40% new infection). Conclusion: Prevalence of chronic HBV, chronic HCV and HIV infections in our study population is higher compared to the Dutch population, thus emphasizing the importance of case finding for these infections through primary care and public health in this specific group of migrants. Screening uptake could be improved by on-site testing. [ABSTRACT FROM AUTHOR]

Several outbreaks of Hepatitis A virus (HAV) were recently documented among men who have sex with men (MSM) in Europe. We investigated the HAV incidence among MSM in Amsterdam, the Netherlands; and HAV seroprevalence and HAV vaccination decision among MSM visiting the Sexually Transmitted Infection (STI) clinic in Amsterdam. Using surveillance data from 1992 to 2017 of MSM with acute HAV in Amsterdam, we estimated the incidence by calendar year and age. We explored HAV seroprevalence by calendar year and age, determinants for HAV seropositivity, and opting-in/out for HAV vaccination using data collected among MSM that visited the STI clinic between 2006 and 2017 and were included in a nationwide Hepatitis B virus (HBV) vaccination programme. Offering HAV vaccination at the STI clinic differed over three consecutive periods: not offered, offered for free, or offered for 75 euros. Logistic regression analyses were used to explore determinants. HAV incidence increased in 2016/17 after 4 years of absence and peaked in MSM around 35 years of age. Among MSM visiting the STI clinic, HAV seroprevalence was 37% (95%CI = 35–40%), which was constant over the period 2006–2017, and increased with age (p < 0.001). Determinants for HAV seropositivity in multivariable analysis were: older age (p < 0.001), originating from an HAV endemic country (p < 0.001), and being HBV seropositive (p = 0.001). MSM opted-in more frequently when HAV vaccination was offered for free versus paid (89% versus 11%, respectively; p < 0.001). Younger MSM were less inclined to vaccinate when payment was required (p = 0.010). Post-hoc analyses showed that 98% versus 46% of MSM visiting the Amsterdam STI clinic would be protected against HAV infection if HAV vaccination was offered for free or for 75 euros, respectively. The MSM population of Amsterdam is vulnerable to a new HAV outbreak. We strongly recommend that MSM have access to free hepatitis A vaccination. [ABSTRACT FROM AUTHOR]

Urban canal swimming events are popular in the Netherlands. In 2015, two city canal swimming events took place, in Utrecht (Utrecht Singel Swim, USS) and in Amsterdam (Amsterdam City Swim, ACS). This prospective study characterizes the health risks associated with swimming in urban waters. Online questionnaires were sent to 160 (USS) and 2,692 (ACS) participants, with relatives of participants who did not swim completing the questionnaire as a control. Swimming water specimens and stool specimens of diarrheic participants in the ACS group were analysed. A total of 49% of USS and 51% of ACS swimmers returned their questionnaires. Nine percent of USS swimmers and 4% of non-swimmers reported gastrointestinal complaints (aRR 2.1; 95% CI: 0.3–16), while a total of 31% of ACS swimmers and 5% of non-swimmers reported gastrointestinal complaints (aRR 6.3; 95% CI: 4.1–9.5). AGI risk among ACS participants was directly related to increasing number of mouthfuls of water swallowed. Various norovirus genotypes were detected in five out of seven stool specimens taken from ACS participants and in all three tested ACS water samples. We conclude that the AGI risk among open-water swimmers in urban areas depends on the circumstances around the event. The epidemiological curve, the statistical association between swimming and AGI, and the microbiological evidence for norovirus in stool and water specimens suggest that AGI outbreak after the ACS event was due to water contamination by multiple norovirus strains, which is possibly linked to sewage overflow due to prior heavy rainfall. There is need for more targeted preventive measurements and recommendations for organizers, municipal authorities and participants to prevent this reoccurring in the future. [ABSTRACT FROM AUTHOR]

Background & Aims: In the Netherlands, transmission of hepatitis B virus occurs mainly within behavioural high-risk groups, such as in men who have sex with men. Therefore, a vaccination programme has targeted these high-risk groups. This study evaluates the impact of the vaccination programme targeting Amsterdam’s large population of men who have sex with men from 1998 through 2011. Methods: We used Amsterdam data from the national database of the vaccination programme for high-risk groups (January 1, 1998 to December 31, 2011). Programme and vaccination coverage were estimated with population statistics. Incidence of acute hepatitis B was analyzed with notification data from the Amsterdam Public Health Service (1992–2011). Mathematical modelling accounting for vaccination data and trends in sexual risk behaviour was used to explore the impact of the programme. Results: At the end of 2011, programme coverage was estimated at 41% and vaccination coverage from 30% to 38%. Most participants (67%) were recruited from the outpatient department for sexually transmitted infections and outreach locations such as saunas and gay bars. Incidence of acute hepatitis B dropped sharply after 2005. The mathematical model in which those who engage most in high-risk sex are vaccinated, best explained the decline in incidence. Conclusions: Transmission of hepatitis B virus among Amsterdam’s men who have sex with men has decreased, despite ongoing high-risk sexual behaviour. Vaccination programmes targeting men who have sex with men do not require full coverage; they may be effective when those who engage most in high-risk sex are reached. [Copyright &y& Elsevier]