Hepatitis C virus infection is uncommon at baseline and during follow-up among individuals using PrEP in the Dutch national PrEP programme between 2019 and 2022.

OBJECTIVES: Studies showed that men who have sex with men (MSM), including those using pre-exposure prophylaxis (PrEP), are at increased risk of hepatitis C virus (HCV) infection. We evaluated HCV prevalence and incidence, along with their associated determinants, in a cohort of PrEP-using individuals in the Netherlands. METHODS: In 2019, the Netherlands launched a 5-year national programme that offers subsidised PrEP to eligible individuals. We used prospectively collected data from individuals registered in this programme between 2019 and 2022. Individuals underwent annual testing for HCV antibodies and additional HCV-RNA testing when antibodies were present. We calculated the prevalence of past/current HCV infection at first visit and overall incidence rate (IR) during follow-up. Univariable logistic and Poisson regression models were used to identify determinants associated with past/current prevalent or incident HCV infection, respectively. Behavioural factors referred to those occurring in the previous 6 months. RESULTS: A total of 10 563 (n=10 319, 97.7% MSM) were included. At first visit, 66 of 10 563 (0.6%) had a past/current HCV infection, which was associated with older age [odds ratio (OR) per 10 years=1.57, 95% confidence interval (CI)=1.31 to 1.88], the use of PrEP before first visit (OR=3.03, 95% CI=1.79 to 5.13), receptive condomless anal sex (CAS) (OR=2.73, 95% CI=1.25 to 5.98), chemsex (OR=2.44, 95% CI=1.49 to 3.99) and injecting drug use (IDU) (OR=6.61, 95% CI=2.35 to 18.61). Among 9851 individuals contributing to 17 150 person-years (PYs) of follow-up, 64 incident HCV infections (IR=0.37 per 100 PYs, 95% CI=0.29 to 0.48) were identified. Factors associated with incident HCV infection were receptive CAS [incidence rate ratio (IRR)=2.59, 95% CI=1.12 to 6.02], chemsex (IRR=1.78, 95% CI=1.06 to 2.98), sexually transmitted infection diagnosis (IRR=2.30, 95% CI=1.23 to 4.31) and IDU (IRR=6.15, 95% CI=2.20 to 17.18). CONCLUSIONS: Past/current prevalence and incidence of HCV were low among individuals in the Dutch PrEP programme. Infections were associated with behaviour known to be associated with HCV. Instead of annual HCV testing, as stated in most PrEP care guidelines, testing frequency for HCV could be based on behaviours associated with HCV acquisition.

Chlamydia trachomatis, Neisseria gonorrhoea, and Trichomonas vaginalis infections among pregnant women and male partners in Dutch midwifery practices: prevalence, risk factors, and perinatal outcomes.

BACKGROUND: Antenatal screening for HIV, syphilis and HBV has been successfully implemented in The Netherlands, but data on other STI among pregnant women or male partners are limited. Our objectives: (i) to assess the prevalence of Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG) and Trichomonas vaginalis (TV) among pregnant women and male partners, (ii) to identify risk factors for these STI during pregnancy, and (iii) to identify adverse perinatal outcomes (APO) associated with STI. METHODS: Cross-sectional study. Pregnant women aged ≤ 30 years (n = 548) and male partners (n = 425) were included at 30 midwifery practices during 2012-2016. Participants provided a self-collected vaginal swab (women) or urine sample (men) and completed a questionnaire. Perinatal data were derived from pregnancy cards. APO was defined as premature rupture of membranes, preterm delivery, low birthweight, stillbirth, neonatal conjunctival and respiratory infections. Data were analysed by logistic regression. RESULTS: STI were present in 2.4% of pregnant women (CT 1.8%, NG 0.4%, TV 0.4%), and in 2.2% of male partners (CT 2.2%, NG 0.2%, TV 0%). Of young women (≤ 20 years), 12.5% had a CT infection. Prevalent STI during pregnancy was associated with female young age (≤ 20 years vs ≥ 21 years) (adjusted OR 6.52, CI 95%: 1.11-38.33), male non-Western vs Western background (aOR 9.34, CI 2.34-37.21), and female with ≥ 2 sex partners < 12 months vs 0-1 (aOR 9.88, CI 2.08-46.91). APO was not associated with STI, but was associated with female low education (aOR 3.36, CI 1.12-10.09), complications with previous newborn (aOR 10.49, CI 3.21-34.25 vs no complications) and short duration (0-4 years) of relationship (aOR 2.75, CI 1.41-5.39 vs ≥ 5 years). Small-for-gestational-age was not associated with STI, but was associated with female low education (aOR 7.81, 2.01-30.27), female non-Western background (aOR 4.41, 1.74-11.17), and both parents smoking during pregnancy (aOR 2.94, 1.01-8.84 vs both non-smoking). CONCLUSIONS: Prevalence of STI was low among pregnant women and male partners in midwifery practices, except for CT among young women. The study could not confirm previously observed associations between STI and APO, which is probably due to low prevalence of STI, small study sample, and presumed treatment for STI.

Antenatal screening for HIV, syphilis and HBV has been successfully implemented in The Netherlands, but data on other STI among pregnant women or male partners are limited. Our objectives were: (i) to assess the prevalence of Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG) and Trichomonas vaginalis (TV) among pregnant women and male partners, (ii) to identify risk factors for these STI during pregnancy, and (iii) to identify adverse perinatal outcomes (APO) associated with STI.Pregnant women aged ≤ 30 years and male partners were included at 30 midwifery practices. Women provided a vaginal swab, partners a urine sample; both completed a questionnaire. Perinatal data were derived from midwives.STI were present in 2.4% of pregnant women (CT 1.8%, NG 0.4%, TV 0.4%), and in 2.2% of male partners (CT 2.2%, NG 0.2%, TV 0%). Of women ≤ 20 years, 12.5% had a CT infection. Prevalent STI during pregnancy was associated with female young age, male non-Western background, and female with ≥ 2 sex partners < 12 months. APO was not associated with STI, but was associated with female low education, complications with previous newborn, and short duration of the relationship. Small-for-gestational-age was not associated with STI, but was associated with female low education, female non-Western background, and both parents smoking during pregnancy.Prevalence of STI was low among pregnant women and male partners in midwifery practices, except for CT among young women. The study could not confirm previously observed associations between STI and APO. Probably due to low prevalence of STI, small study sample, and presumed treatment for STI.

Impact of frequent testing on the transmission of HIV and N. gonorrhoeae among men who have sex with men: a mathematical modelling study.

OBJECTIVES: To investigate the impact and efficiency of combined testing for HIV and other STIs on HIV and STI transmission among men who have sex with men (MSM) and to assess what subgroups of MSM should be targeted for frequent testing. METHODS: We developed an agent-based transmission model that simulates infection with HIV or Neisseria gonorrhoeae (NG) among MSM. We examined scenarios with increased percentages of MSM getting tested six monthly, among all MSM or only specific subgroups of MSM (defined according to recent gonorrhoea, number of partners and engagement in condomless anal intercourse (CAI)) and scenarios with reduced intervals between HIV/STI tests. RESULTS: The most efficient strategies were those with increased percentage of MSM getting tested every 6 months among MSM with a recent gonorrhoea diagnosis; or among MSM who had CAI and ≥10 partners; or MSM who had ≥10 partners. Over 10 years, these strategies resulted in 387-718 averted HIV infections and required 29-164 additional HIV tests per averted HIV infection or one to seven additional gonorrhoea tests per averted NG infection. The most effective strategy in reducing HIV transmission was the one where the intervals between tests were reduced by half, followed by the strategy with increased percentage of MSM getting tested every 6 months among all MSM. Over 10 years, these strategies resulted in 1362 and 1319 averted HIV infections, but required 663 and 584 additional HIV tests per averted HIV infection, respectively. CONCLUSIONS: Targeting MSM with recent gonorrhoea diagnosis or MSM with many partners is efficient in terms of HIV/STI tests needed to prevent new HIV or NG infections. Major reductions in HIV incidence can be achieved with consistent HIV/STI testing every 6 months among larger groups, including low-risk MSM. To impede HIV transmission, frequent testing should be combined with other prevention measures.

Evaluating progress towards triple elimination of mother-to-child transmission of HIV, syphilis and hepatitis B in the Netherlands.

BACKGROUND: In 2014 the World Health Organisation (WHO) established validation criteria for elimination of mother-to-child transmission (EMTCT) of HIV and syphilis. Additionally, the WHO set targets to eliminate hepatitis, including hepatitis B (HBV). We evaluated to what extent the Netherlands has achieved the combined WHO criteria for EMTCT of HIV, syphilis and HBV. METHODS: Data of HIV, syphilis and HBV infections among pregnant women and children (born in the Netherlands with congenital infection) for 2009-2015, and data required to validate the WHO criteria were collected from multiple sources: the antenatal screening registry, the HIV monitoring foundation database, the Perinatal Registry of the Netherlands, the national reference laboratory for congenital syphilis, and national HBV notification data. RESULTS: Screening coverage among pregnant women was > 99% for all years, and prevalence of HIV, syphilis and HBV was very low. In 2015, prevalence of HIV, syphilis and HBV was 0.06, 0.06 and 0.29%, respectively. No infections among children born in the Netherlands were reported in 2015 for all three diseases, and in previous years only sporadic cases were observed In 2015, treatment of HIV positive pregnant women was 100% and HBV vaccination of children from HBV positive mothers was > 99%. For syphilis, comprehensive data was lacking to validate WHO criteria. CONCLUSIONS: In the Netherlands, prevalence of maternal HIV, syphilis and HBV is low and congenital infections are extremely rare. All minimum WHO criteria for validation of EMTCT are met for HIV and HBV, but for syphilis more data are needed to prove elimination.

Chlamydia screening and prophylactic treatment in termination of pregnancy clinics in the Netherlands and Great Britain: a qualitative study.

BACKGROUND: Women having a termination of pregnancy (TOP) have higher rates of Chlamydia trachomatis (CT) than the general population. In this study, we explored CT treatment and prevention in Dutch TOP clinics in comparison to that provided in Great Britain (GB). METHODS: A qualitative study including 14 semi-structured interviews with health care professionals (HCPs) in TOP clinics (the Netherlands: 9, GB: 5). Interviews were recorded, transcribed, and analysed by thematic content analysis. RESULTS: Prophylactic treatment with azithromycin is routinely prescribed after surgical TOP, but not after medical TOP ('abortion pill'). Sexually transmitted infections (STI) tests are offered to clients who are considered at high risk of having STI. Uptake varies according to health insurance coverage of STI testing. Some Dutch clinics are able to provide free testing for women under 25 years of age. Sexual health counselling is often limited to discussing birth control. The major difference between the Netherlands and GB is that GB TOP clinics more often offer free STI testing and prophylaxis to their clients. CONCLUSION: HCPs in Dutch TOP clinics consider STI testing an important part of their service, but financial barriers prevent testing on location. Dutch TOP clinics should offer STI tests to all women, and collaboration with public health services could improve STI testing and counselling for young people. Furthermore, clinics should treat all TOP clients with prophylactic azithromycin. This could prevent CT and other upper genital tract post-abortion infections.

Chlamydia screening is not cost-effective at low participation rates: evidence from a repeated register-based implementation study in The Netherlands.

OBJECTIVE: In three pilot regions of The Netherlands, all 16-29 year olds were invited to participate in three annual rounds of Chlamydia screening. The aim of the present study is to evaluate the cost-effectiveness of repeated Chlamydia screening, based on empirical data. METHODS: A mathematical model was employed to estimate the influence of repeated screening on prevalence and incidence of Chlamydial infection. A model simulating the natural history of Chlamydia was combined with cost and utility data to estimate the number of major outcomes and quality-adjusted life-years (QALYs) associated with Chlamydia. Six screening scenarios (16-29 years annually; 16-24 years annually; women only; biennial screening; biennial screening women only; screening every five years) were compared with no screening in two sexual networks, representing both lower ('national network') and higher ('urban network') baseline prevalence. Incremental cost-effectiveness ratios (ICERs) for the different screening scenarios were estimated. Uncertainty and sensitivity analyses were performed. RESULTS: In all scenarios and networks, cost per major outcome averted are above €5000. Cost per QALY are at least €50,000. The default scenario as piloted in the Netherlands was least cost-effective, with ICERs of €232,000 in the national and €145,000 in the urban sexual network. Results were robust in sensitivity analyses. CONCLUSIONS: It is unlikely that repeated rounds of Chlamydia screening will be cost-effective. Only at high levels of willingness to pay for a QALY (>€50,000) screening may be more cost-effective than no screening.

Chlamydia test results were associated with sexual risk behavior change among participants of the Chlamydia screening implementation in The Netherlands.

OBJECTIVE: To examine the effect of a laboratory-confirmed Chlamydia trachomatis (Ct) test result on subsequent sexual risk behavior in a large population-based screening program. METHODS: The study population consisted of 16- to 29-year-old participants of the Chlamydia Screening Implementation who completed Ct testing and questionnaires in 2 or more rounds. The influence of a Ct test result on sexual behavior was analyzed by generalized estimating equation models, in which the Ct test result of the previous round was the independent variable and 1 of the 8 sexual risk behavior indicators was the dependent variable, adjusted for covariates. RESULTS: Of 48,910 Chlamydia Screening Implementation participants with completed questionnaires and test results, 14.1% (n = 6802) and 2.6% (n = 1272) completed 2 and 3 rounds, respectively, and were included in this study. Analysis showed that Ct positives less often reported to "never" use condoms with a casual partner (%change pretest/posttest = -5.7% [-10.3 to -0.9]), whereas Ct negatives less often reported to "always" use condoms with a casual partner (-4.6% [-6.4 to -2.8]; odds ratio [95% confidence interval], 1.75 [1.09 to 2.80]). Ct positives also had more sexual partners in the subsequent round than did participants with a Ct-negative test result (relative risk [95% confidence interval], 1.14 [1.01 to 1.29]). CONCLUSIONS: Ct test results were associated with subsequent sexual risk behavior. In general, Ct positives were more likely to change their behavior after a Ct test result in a more positive and protective direction than Ct negatives, who were more likely to change their behavior toward more risky behavior. Effects over time after a Ct test should be investigated further, especially in the Ct negatives.

Comparing databases: determinants of sexually transmitted infections, HIV diagnoses, and lack of HIV testing among men who have sex with men.

BACKGROUND: Early detection and treatment of STI/HIV are public health priorities. Our objective was to compare characteristics of men who have sex with men (MSM) in Dutch data available in 2010 from EMIS, an international internet survey, Schorer Monitor, a Dutch internet survey, and data from STI- clinic visits, since these might be subject to different and unknown biases. METHODS: Data from Dutch MSM Internet Surveys (EMISNL N = 3,787; Schorer Monitor, SMON N = 3,602), and 3,800 STI clinic visits (SOAP) were combined into one dataset. We included factors that were measured in all three databases. The socio-demographics included were age (at the time of the survey), zip code, and ethnicity. Behavioural variables included were the number of sexual partners, condom use with last sexual partner, drug use, being diagnosed with STI, being diagnosed with HIV, and HIV testing. Outcomes we investigated were being diagnosed with STI, HIV, and never been tested for HIV. RESULTS: Logistic regressions showed that determinants for being diagnosed with STI were having more sexual partners, drug use, and having had an HIV test (aORs 1.3 to 17.1) in EMIS and SMON. Determinants for being diagnosed with HIV in all three databases were older age, living in Amsterdam, and having more partners (aORs 1.8 to 4.4). In EMIS and SMON, drug use, non-condom use, and having STI were additional determinants (aORs 1.6 to 8.9). Finally, determinants associated with never been tested for HIV were being younger (only SOAP), living outside of Amsterdam, having fewer partners, no drug use, and no STI (aORs 0.2 to 0.8). CONCLUSIONS: Risk factors from internet surveys were largely similar, but differed from STI clinics, possibly because it involves self-reports rather than diagnoses or because of differences in timing. The difference between the internet surveys and STI clinic data is much less pronounced for having never been tested, suggesting both are appropriate for this outcome. These findings shed light on conclusions drawn from different data sources, as well as the comparability of recruitment strategies, the robustness of risk factors, consequences of phrasing questions differently, and on (policy) implications based on different data sources.

Do sexual risk behaviour, risk perception and testing behaviour differ across generations of migrants?

BACKGROUND: Behaviour and related health outcomes of migrants have been suggested to shift towards the practices of the indigenous population of the host country. To investigate this, we studied generational differences in sexual behaviour between first- and second-generation migrants (FGMs and SGMs) in The Netherlands. METHODS: In 2003-05, persons aged 16-70 years with origins in Surinam, the Antilles and Aruba were interviewed on their sexual behaviour in The Netherlands and their country of origin. The relationship of generation, age at migration and sexual behaviour was studied by multinomial logistic regression analyses. RESULTS: Generational differences were observed regarding concurrent partnerships, anal sex and history of sexually transmitted infection. Compared with FGMs who migrated at an age >25 years, those who migrated between 10 and 25 years of age were more likely to report concurrency [odds ratio (OR): 1.52, 95% confidence interval (CI): 1.14-2.04], whereas SGMs were less likely to report concurrency (OR: 0.65, 95% CI: 0.43-0.98). FGMs who migrated before the age of 10 were more likely to have had anal sex (OR: 1.90, 95% CI: 1.34-2.71) or a sexually transmitted infection diagnosis (OR: 1.80, 95% CI: 1.20-2.71) than those who had migrated at >25 years of age. CONCLUSION: Our study shows that not only SGMs but also FGMs who migrated at an early age tend to differ from the sexual patterns of FGMs who migrated at an older age. Generational differences in sexual behaviour could be explained by acculturation and increased identity with the values of the host country.

A survey-based assessment of rates and covariates of mpox diagnosis and vaccination provides evidence to refine eligibility criteria for mpox vaccination among gay, bisexual and other men who have sex with men in the Netherlands.

Background: The 2022 multicountry mpox outbreaks predominantly affected gay, bisexual and other men who have sex with men (GBMSM) in non-endemic countries, including in the Netherlands. We conducted a survey-based assessment of the alignment between the risk factors associated with mpox diagnosis among GBMSM in the Netherlands and the eligibility criteria used in 2022 for vaccinating this group, with the aim to refine these criteria. Methods: An online self-report survey was conducted among adult GBMSM in the Netherlands between 29 July and 30 August 2022, corresponding to the first month of the Dutch mpox vaccination campaign. GBMSM were recruited via advertisements on social media and gay dating apps. Participants reported on their sexual behaviour, mpox diagnosis, and/or (initial) mpox vaccination since the start of the outbreak. Covariables of mpox diagnosis and vaccination were assessed using logistic regression analyses. Results: Of the 2,460 participants, 73 (3.0%, 95% CI 2.3-3.6%) were diagnosed with mpox and 485 (19.7%, 95% CI 18.1-21.3%) had received (initial) mpox vaccination. Using sample weighting, we estimated that, of the GBMSM population aged 18-80 years in the Netherlands, 1.1% (95% CI 0.7-1.6%) had been diagnosed with mpox and 7.8% (95% CI 6.8-8.9%) had received (initial) vaccination. HIV-PrEP use, living with HIV, reporting ≥20 sex partners in the past 12 months, and sex in sex venues/parties in the past 2 months were independent risk factors for mpox diagnosis. Except for sex in sex venues/parties, these variables were also independently associated with mpox vaccination. Conclusion: This study provides novel evidence regarding the degree to which the 2022 eligibility criteria for mpox vaccination align with the risk factors for mpox among GBMSM in the Netherlands. The findings contribute to a refinement of the eligibility criteria for mpox vaccination, to which sex in sex venues/parties should be added.

High yield of reinfections by home-based automatic rescreening of Chlamydia positives in a large-scale register-based screening programme and determinants of repeat infections.

INTRODUCTION: In a systematic internet-based Chlamydia Screening Implementation Programme in The Netherlands, all chlamydia-positive participants automatically received a testkit after 6 months to facilitate early detection of repeat infections. The authors describe participation in repeat testing and prevalence and determinants of repeat infection during three consecutive annual screening rounds. METHODS: Data collection included information on testkits sent, samples received and results of laboratory tests at time of baseline test and retest; (sexual) behavioural variables and socio-demographic variables were assessed. Chlamydia positives were requested to answer additional questions about treatment and partner notification 10 days after checking their results. RESULTS: Retest rate was 66.3% (2777/4191). Retest chlamydia positivity was 8.8% (242/2756) compared with a chlamydia positivity at first screening test of 4.1%. Chlamydia positivity was significantly higher in younger age groups (14.6% in 16-19 years, 8.5% and 5.5% in 20-24 and 25-29 years; p<0.01); in participants with lower education (15.2% low, 11.1% medium and 5.1% high; p<0.001) and in Surinamese/Antillean (13.1%), Turkish/Moroccan (12.9%) and Sub-Saharan African participants (18.6%; p<0.01). At baseline, 88.7% infected participants had reportedly been treated and treatment of current partner was 80.1%. DISCUSSION: Automated retesting by sending a testkit after 6 months to all chlamydia positives achieved high retest uptake and yielded a positivity rate twice as at baseline and can therefore be recommended as an additional strategy for chlamydia control. The high rate of repeat infections among known risk groups suggests room for improvement in patient case management and in effective risk reduction counselling.

Systematic selection of screening participants by risk score in a Chlamydia screening programme is feasible and effective.

OBJECTIVES: Systematic screening for Chlamydia trachomatis by individual invitation can be optimised by filtering participants on risk profile, excluding people at no or low risk. The authors investigated this technique in a large-scale chlamydia screening programme in The Netherlands in one rural region where relatively low prevalence was expected (<2%). METHODS: Invitees were alerted by personal letter to log in to http://www.chlamydiatest.nl and fill in an 8-item questionnaire. Only invitees with sufficient score could proceed to request a test kit. The authors investigated the effect of selection on participation, positivity and acceptability in three screening rounds and on the number needed to invite and the number needed to screen. RESULTS: The selection led to exclusion of 36% of potential participants and a positivity rate of 4.8% among participants, achieving similar number needed to screen values in the rural and urban areas. Higher scores were clearly related to higher positivity rates. Persons who were excluded from participation did not have a lower response in the next round. The acceptability study revealed disappointment about exclusion of 30% of excluded participants but most approved of the screening set-up. CONCLUSIONS: Systematic selection of screening participants by risk score is feasible and successful in realising higher positivity rates. A somewhat stricter selection could be applied in the rural and urban areas of the screening programme. Multiple-item selection with a cut-off total score may work better than, more commonly used, selection by single criteria, especially in low-risk populations. Acceptability of selection is high but could still be improved by better communication on expectations.

Who participates in the Dutch Chlamydia screening? A study on demographic and behavioral correlates of participation and positivity.

BACKGROUND: In the Netherlands, an Internet-based Chlamydia Screening Implementation was initiated in 3 regions, aiming to reduce population prevalence by annual testing and treatment of people aged 16 to 29 years. We studied who was reached in the first screening round by relating participation and chlamydia positivity to sociodemographic and sexual risk factors. METHODS: Data from the 2008/2009 screening round were analyzed (261,025 screening invitations, 41,638 participants). Participation rates were adjusted for the sexually active population. Sociodemographic and behavioral correlates of screening participation and positivity were studied by (multilevel) logistic regression models. RESULTS: The overall adjusted participation rate in the first screening round was 19.5% (95% confidence interval, 19.4-19.7) among sexually active people (women, 25%; men, 13%). Sociodemographic factors associated with lower participation were male gender (odds ratio [OR], male 1 vs. female 1.8), young age (OR, 16-19 1 vs. older groups 1.7-2.1), non-Dutch origin (OR between 0.7-0.9), lower education (OR, low 1 vs. high 1.4), high community risk level (0.8), and low socioeconomic status (0.9). Behavioral factors associated with lower participation were a long-standing relationship (0.7) and no reported history or symptoms of sexually transmitted infections (no symptoms, 0.4-0.6) . Factors most strongly related to higher Ct positivity were young age (OR, 1 vs. older groups 0.5-0.8), non-Dutch origin (1.4-2.8), non-Dutch steady partner (1.9-2.7), residence in a high-risk area (1.4-1.5), lower education (high, 0.3-0.5), and a history or symptoms of sexually transmitted infection (no symptoms, 0.4-0.6). CONCLUSIONS: Sociodemographic factors associated with lower participation were also associated with higher Ct positivity, showing that high-risk demographic groups are more difficult to mobilize than low-risk groups. Independent of this, higher behavioral risk levels were associated with higher participation rates, suggesting self-selection for screening based on the persons' risk (perception) in both low- and high community risk groups. Our study shows the complexity of the process, including individual and community factors that also interact, when screening for chlamydia.

Keeping participants on board: increasing uptake by automated respondent reminders in an Internet-based chlamydia screening in the Netherlands.

BACKGROUND: Effectiveness of Chlamydia screening programs is determined by an adequate level of participation and the capturing of high-risk groups. This study aimed to evaluate the contribution of automated reminders by letter, email and short message service (SMS) on package request and sample return in an Internet-based Chlamydia screening among people aged 16 to 29 years in the Netherlands. METHODS: Individuals not responding to the invitation letter received a reminder letter after 1 month. Email- and SMS-reminders were sent to persons who did not return their sample. It was examined to what extent reminders enhanced the response rate (% of package requests) and participation rate (% of sample return). Sociodemographic and behavioural correlates of providing a cell phone number and participation after the reminder(s) were studied by logistic regression models. RESULTS: Of all respondents (screening round 1: 52,628, round 2: 41,729), 99% provided an email address and 72% a cell phone number. Forty-two percent of all package requests were made after the reminder letter. The proportion of invitees returning a sample increased significantly from 10% to 14% after email/SMS reminders (round 2: from 7% to 10%). Determinants of providing a cell-phone number were younger age (OR in 25-29 year olds versus 16-19 year olds = 0.8, 95%CI 0.8-0.9), non-Dutch (OR in Surinam/Antillean versus Dutch = 1.3, 95%CI 1.2-1.4, Turkish/Moroccan: 1.1, 95%CI 1.0-1.2, Sub Sahara African: 1.5, 95%CI 1.3-1.8, non-Western other 1.1, 95%CI 1.1-1.2), lower educational level (OR in high educational level versus low level = 0.8, 95%CI 0.7-0.9), no condom use during the last contact with a casual partner (OR no condom use versus condom use 1.2, 95%CI 1.1-1.3), younger age at first sexual contact (OR 19 years or older versus younger than 16: 0.7, 95%CI 0.6-0.8). Determinants for requesting a test-package after the reminder letter were male gender (OR female versus male 0.9 95%CI 0.8-0.9), non-Dutch (OR in Surinam/Antillean versus Dutch 1.3, 95%CI 1.2-1.4, Turkish/Moroccan: 1.4, 95%CI 1.3-1.5, Sub Sahara African: 1.4, 95%CI 1.2-1.5, non-Western other: 1.2, 95%CI 1.1-1.2), having a long-term steady partnership (long-term versus short-term.1.2 95%CI 1.1-1.3). Email/SMS reminders seem to have resulted in more men and people aged 25-29 years returning a sample. CONCLUSIONS: Nearly all respondents (99.5%) were reachable by modern communication media. Response and participation rates increased significantly after the reminders. The reminder letters also seemed to result in reaching more people at risk. Incorporation of automated reminders in Internet-based (Chlamydia) screening programs is strongly recommended.

Hepatitis C virus seroprevalence in the Netherlands.

A population-based anti-hepatitis C virus (HCV) prevalence is important for surveillance purposes and it provides an insight into the burden of disease. In The Netherlands, a recent HCV seroprevalence estimate is not available. This national population-based cross-sectional serosurvey (PIENTER-2) resulted in a weighted national HCV seroprevalence of 0.30% (95% confidence interval 0.05-0.55%). About 70% of the HCV positive individuals found were born in an HCV-endemic country.

Mpox vaccination willingness, determinants, and communication needs in gay, bisexual, and other men who have sex with men, in the context of limited vaccine availability in the Netherlands (Dutch Mpox-survey).

Introduction: In the 2022 multicountry mpox (formerly named monkeypox) outbreak, several countries offered primary preventive vaccination (PPV) to people at higher risk for infection. We study vaccine acceptance and its determinants, to target and tailor public health (communication-) strategies in the context of limited vaccine supply in the Netherlands. Methods: Online survey in a convenience sample of gay, bisexual and other men who have sex with men, including transgender persons (22/07-05/09/2022, the Netherlands). We assessed determinants for being (un)willing to accept vaccination. We used multivariable multinominal regression and logistic regression analyses, calculating adjusted odds ratios (aOR) and 95 percent confidence-intervals. An open question asked for campaigning and procedural recommendations. Results: Of respondents, 81.5% (n = 1,512/1,856) were willing to accept vaccination; this was 85.2% (799/938) in vaccination-eligible people and 77.7% (713/918) in those non-eligible. Determinants for non-acceptance included: urbanization (rural: aOR:2.2;1.2-3.7; low-urban: aOR:2.4;1.4-3.9; vs. high-urban), not knowing mpox-vaccinated persons (aOR:2.4;1.6-3.4), and lack of connection to gay/queer-community (aOR:2.0;1.5-2.7). Beliefs associated with acceptance were: perception of higher risk/severity of mpox, higher protection motivation, positive outcome expectations post vaccination, and perceived positive social norms regarding vaccination. Respondents recommended better accessible communication, delivered regularly and stigma-free, with facts on mpox, vaccination and procedures, and other preventive options. Also, they recommended, "vaccine provision also at non-clinic settings, discrete/anonymous options, self-registration" to be vaccinated and other inclusive vaccine-offers (e.g., also accessible to people not in existing patient-registries). Conclusion: In the public health response to the mpox outbreak, key is a broad and equitable access to information, and to low-threshold vaccination options for those at highest risk. Communication should be uniform and transparent and tailored to beliefs, and include other preventive options. Mpox vaccine willingness was high. Public health efforts may be strengthened in less urbanized areas and reach out to those who lack relevant (community) social network influences.

Hepatitis C in the general population of various ethnic origins living in the Netherlands: should non-Western migrants be screened?

BACKGROUND & AIMS: Little is known about the HCV prevalence in non-Western migrant populations. To determine whether targeted HCV screening and prevention programs for migrants are needed, we examined HCV prevalence and determinants among non-Western, Western migrants, and the native Dutch population in the Netherlands. METHODS: Data were obtained from four surveys: (1) 3895 heterosexual visitors recruited during biannual surveys at the STI-clinic Amsterdam, 2007-2009; (2) random sample of 4563 pregnant women in Amsterdam, 2003; (3) population-based random sample of 1309 inhabitants of Amsterdam, 2004; (4) population-based random sample of 4428 people living in the Netherlands, 2006-2007. Characteristics associated with HCV-positivity were examined and phylogenetic analysis was used to obtain insight in the geographical origin of HCV strains. RESULTS: HCV seroprevalence in the four surveys was low (0.3-0.6%). In total 4860/14,195 (34%) were non-Western and 9329/14,195 (66%) Western participants (including Dutch). First-generation non-Western migrants were more likely to be HCV-positive (0.7-2.3%) than Western participants (0.1-0.4%). Except for survey 3, second-generation non-Western migrants had a lower HCV prevalence than first-generation migrants, comparable to Western migrants and the Dutch population. Phylogenetic analysis showed that the majority of the HCV-positive, first-generation non-Western non-European migrants were infected with endemic strains which are rarely observed in Europe. CONCLUSIONS: First-generation non-Western migrants are at increased risk for HCV. Phylogenetic analysis suggests that transmission likely took place in the country of origin, causing introduction but no further transmission of endemic HCV strains in the Netherlands. HCV screening and prevention programs should target first-generation, but not second-generation, non-Western migrants.

Acceptability of the internet-based Chlamydia screening implementation in the Netherlands and insights into nonresponse.

BACKGROUND: The study assessed the acceptability of internet-based Chlamydia screening using home-testing kits among 16- to 29-year-old participants and nonparticipants in the first year of a Chlamydia Screening Implementation program in the Netherlands. METHODS: Questionnaire surveys were administered to randomly selected participants (acceptability survey) and nonparticipants (nonresponse survey) in 3 regions of the Netherlands where screening was offered. Participants received email invitations to an online survey; nonparticipants received postal questionnaires. Both surveys enquired into opinions on the screening design, reasons for (non-) participation and future willingness to be tested. RESULTS: The response rate was 63% (3499/5569) in the acceptability survey and 15% (2053/13,724) in the nonresponse survey. Primary motivation for participating in the screening was "for my health" (63%). The main reason for nonresponse given by sexually active nonparticipants was "no perceived risk of infection" (40%). Only 2% reported nonparticipation due to no internet access. Participants found the internet (93%) and home-testing (97%) advantages of the program, regardless of test results. Two-thirds of participants would test again, 92% via the screening program. Half of nonparticipants were appreciative of the program design, while about 1 in 5 did not like internet usage, home-testing, or posting samples. CONCLUSIONS: The screening method was highly acceptable to participants. Nonparticipants in this survey were generally appreciative of the program design. Both groups made informed choices about participation and surveyed low-risk nonparticipants accurately perceived their low-risk status. Although many nonparticipants were not reached by the nonresponse survey, current insights on acceptability and nonresponse are undoubtedly valuable for evaluation of the current program.

Antenatal screening for HIV, hepatitis B and syphilis in the Netherlands is effective.

BACKGROUND: A screening programme for pregnant women has been in place since the 1950s in the Netherlands. In 2004 universal HIV screening according to opting out was implemented. Here, we describe the evaluation of the effectiveness of antenatal screening in the Netherlands for 2006-2008 for HIV, hepatitis B virus (HBV) and syphilis in preventing mother-to-child transmission, by using various data sources. METHODS: The results of antenatal screening (2006-2008) were compared with data from pregnant women and newborns from other data sources. RESULTS: Each year, around 185,000 pregnant women were screened for HIV, HBV and syphilis. Refusal rates for the screening tests were low, and were highest (0.2%) for HIV. The estimated annual prevalence of HIV among pregnant women was 0.05%.Prior to the introduction of screening, 5-10 children were born with HIV annually After the introduction of screening in 2004, only 4 children were born with HIV (an average of 1 per year). Two of these mothers had become pregnant prior to 2004; the third mother was HIV negative at screening and probably became infected after screening; the fourth mother's background was unknown. Congenital syphilis was diagnosed in fewer than 5 newborns annually and 5 children were infected with HBV. In 3 of these, the mothers were HBeAg positive (a marker for high infectivity). We estimated that 5-10 HIV, 50-75 HBV and 10 syphilis cases in newborns had been prevented annually as a result of screening. CONCLUSIONS: The screening programme was effective in detecting HIV, HBV and syphilis in pregnant women and in preventing transmission to the child. Since the introduction of the HIV screening the number of children born with HIV has fallen dramatically. PREVIOUS PUBLICATION: [Translation from: 'Prenatale screening op hiv, hepatitis B en syphilis in Nederland effectief', published in 'The Dutch Journal of Medicine ' (NTVG, in Dutch)].