Spillover of a hepatitis A outbreak among men who have sex with men (MSM) to the general population, the Netherlands, 2017.

Since 2015, outbreaks of hepatitis A among men who have sex with men (MSM) have been reported worldwide. To examine the impact of these MSM outbreaks in the Netherlands, we combined notification and epidemiological data with sequence analysis. Our results show the hazards of outbreaks within risk-groups spilling over into the largely susceptible general population. One third of the outbreak-related hepatitis A virus genotypes were detected in non-MSM cases

Seroprevalence of varicella-zoster virus and predictors for seronegativity in the Amsterdam adult population

Abstract Background In the Netherlands, infection with varicella-zoster virus (VZV) is considered a benign common childhood illness and routine vaccination against VZV is not done. In 1995 it was estimated that 98-100% of the adult Dutch general population is immune, yet the estimate is based on a database in which a relative small number of people of non-Dutch ethnic origin were represented. As the city of Amsterdam has large immigrant communities originating from various subtropical and tropical countries, such as Morocco, Surinam, and Turkey with probably lower VZV transmission, this study aimed to estimate the seroprevalence of VZV IgG antibodies (anti-VZV) among various ethnic groups in Amsterdam, and identify factors associated with seronegative VZV status. Methods The study was a cross-sectional survey of the Amsterdam population (2004), and the study sample was stratified by age and ethnicity, with deliberate oversampling of minority ethnic groups. Serum samples obtained from 1,341 residents in 2004 were tested for antibodies to VZV. Basic demographic data (gender, age, country of birth, age at immigration and number of children) were also available. Results The anti-VZV seroprevalence in the overall Amsterdam population was estimated to be 94% (95% confidence intervals; 92–96%). Regarding ethnic origin, first generation immigrants (Moroccan immigrants 90%, Surinamese or Antillean immigrants 91%, and Turkish 92%), especially those that migrated after the age of 11 years, were more likely to be anti-VZV seronegative compared to those arriving at an earlier age or those born in the Netherlands (97–98%). Both ethnic origin and generation of immigration were positive predictors for IgG seronegativity to VZV (p Conclusion The results of this study imply that about 4–8% of the general adult Amsterdam population is still susceptible to infection with VZV, and that susceptibility is even higher in some immigrant groups. When assessing the risk of infection after VZV exposure alertness is needed for vulnerable persons like pregnant women, patients with hematological malignancies or organ transplants in particular among first-generation immigrants.</p

Seroprevalence of varicella-zoster virus and predictors for seronegativity in the Amsterdam adult population

Background: In the Netherlands, infection with varicella-zoster virus (VZV) is considered a benign common childhood illness and routine vaccination against VZV is not done. In 1995 it was estimated that 98-100% of the adult Dutch general population is immune, yet the estimate is based on a database in which a relative small number of people of non-Dutch ethnic origin were represented. As the city of Amsterdam has large immigrant communities originating from various subtropical and tropical countries, such as Morocco, Surinam, and Turkey with probably lower VZV transmission, this study aimed to estimate the seroprevalence of VZV IgG antibodies (anti-VZV) among various ethnic groups in Amsterdam, and identify factors associated with seronegative VZV status. Methods: The study was a cross-sectional survey of the Amsterdam population (2004), and the study sample was stratified by age and ethnicity, with deliberate oversampling of minority ethnic groups. Serum samples obtained from 1,341 residents in 2004 were tested for antibodies to VZV. Basic demographic data (gender, age, country of birth, age at immigration and number of children) were also available. Results: The anti-VZV seroprevalence in the overall Amsterdam population was estimated to be 94% (95% confidence intervals; 92-96%). Regarding ethnic origin, first generation immigrants (Moroccan immigrants 90%, Surinamese or Antillean immigrants 91%, and Turkish 92%), especially those that migrated after the age of 11 years, were more likely to be anti-VZV seronegative compared to those arriving at an earlier age or those born in the Netherlands (97-98%). Both ethnic origin and generation of immigration were positive predictors for IgG seronegativity to VZV (p <0.015). No other predictors for seronegativity were found. Conclusion: The results of this study imply that about 4-8% of the general adult Amsterdam population is still susceptible to infection with VZV, and that susceptibility is even higher in some immigrant groups. When assessing the risk of infection after VZV exposure alertness is needed for vulnerable persons like pregnant women, patients with hematological malignancies or organ transplants in particular among first-generation immigrant

Paediatric monkeypox patient with unknown source of infection, the Netherlands, June 2022.

Since May 2022, an international monkeypox (MPX) outbreak has been ongoing in more than 50 countries. While most cases are men who have sex with men, transmission is not restricted to this population. In this report, we describe the case of a male child younger than 10 years with MPX in the Netherlands. Despite thorough source tracing, a likely source of infection has not been identified. No secondary cases were identified in close contacts

Trends in Hepatitis A, B, and Shigellosis Compared With Gonorrhea and Syphilis in Men Who Have Sex With Men in Amsterdam, 1992-2006

Background: Since the mid-1990s, sexually transmitted infections (STIs) among men who have sex with men (MSM) have increased and appear to be related to more risky sexual behavior. We compare trends in hepatitis A, acute hepatitis B, and shigellosis with the trends of gonorrhea and infectious syphilis in Amsterdam MSM more than a period of 15 years. Methods: We used data of all reported hepatitis A, acute hepatitis B, and shigellosis, and from all patients newly diagnosed with gonorrhea and infectious syphilis who visited the Public Health Service STI outpatient department in Amsterdam between January 1, 1992 and December 31, 2006. Results: Hepatitis A incidence remained unchanged in MSM (mean 0.97 per 1000 MSM, range 0.04-2.27), who had 21% of all 1697 infections. Hepatitis B likewise remained unchanged in MSM (mean 0.47 per 1000 MSM, range 0.19-0.77), who had 41% of all 448 infections. Most shigellosis is travel-related (657/974), and 16% of the infections occurred in MSM. Its incidence dropped in general, but not in MSM. Both gonorrhea and infectious syphilis in MSM show a steep increase, mainly after 1998. Discussion: Hepatitis A, B, and shigellosis do not follow the rising trends of conventional STI in MSM, which are believed to result from increased risky sexual behavior. This disparity in trends implies differences in transmission dynamics. Recent molecular epidemiologic studies suggest that clustered transmission in social MSM networks plays a major rol