Antigenic cartography using sera from sequence-confirmed SARS-CoV-2 variants of concern infections reveals antigenic divergence of Omicron.

Large-scale vaccination campaigns have prevented countless hospitalizations and deaths due to COVID-19. However, the emergence of SARS-CoV-2 variants that escape from immunity challenges the effectiveness of current vaccines. Given this continuing evolution, an important question is when and how to update SARS-CoV-2 vaccines to antigenically match circulating variants, similarly to seasonal influenza viruses where antigenic drift necessitates periodic vaccine updates. Here, we studied SARS-CoV-2 antigenic drift by assessing neutralizing activity against variants of concern (VOCs) in a set of sera from patients infected with viral sequence-confirmed VOCs. Infections with D614G or Alpha strains induced the broadest immunity, whereas individuals infected with other VOCs had more strain-specific responses. Omicron BA.1 and BA.2 were substantially resistant to neutralization by sera elicited by all other variants. Antigenic cartography revealed that Omicron BA.1 and BA.2 were antigenically most distinct from D614G, associated with immune escape, and possibly will require vaccine updates to ensure vaccine effectiveness.

Control of complement-induced inflammatory responses to SARS-CoV-2 infection by anti-SARS-CoV-2 antibodies.

Dysregulated immune responses contribute to the excessive and uncontrolled inflammation observed in severe COVID-19. However, how immunity to SARS-CoV-2 is induced and regulated remains unclear. Here, we uncover the role of the complement system in the induction of innate and adaptive immunity to SARS-CoV-2. Complement rapidly opsonizes SARS-CoV-2 particles via the lectin pathway. Complement-opsonized SARS-CoV-2 efficiently induces type-I interferon and pro-inflammatory cytokine responses via activation of dendritic cells, which are inhibited by antibodies against the complement receptors (CR) 3 and 4. Serum from COVID-19 patients, or monoclonal antibodies against SARS-CoV-2, attenuate innate and adaptive immunity induced by complement-opsonized SARS-CoV-2. Blocking of CD32, the FcγRII antibody receptor of dendritic cells, restores complement-induced immunity. These results suggest that opsonization of SARS-CoV-2 by complement is involved in the induction of innate and adaptive immunity to SARS-CoV-2 in the acute phase of infection. Subsequent antibody responses limit inflammation and restore immune homeostasis. These findings suggest that dysregulation of the complement system and FcγRII signaling may contribute to severe COVID-19.

Aberrant neutrophil degranulation in hospitalized patients with COVID-19 partially remains for 6 months.

Neutrophils are important players in COVID-19, contributing to tissue damage by release of inflammatory mediators, including ROS and neutrophil elastase. Longitudinal studies on the effects of COVID-19 on neutrophil phenotype and function are scarce. Here, we longitudinally investigated the phenotype and degranulation of neutrophils in COVID-19 patients (28 nonhospitalized and 35 hospitalized patients) compared with 17 healthy donors (HDs). We assessed phenotype, degranulation, CXCL8 (IL-8) release, and ROS generation within 8 days, at one or 6 month(s) after COVID-19 diagnosis. For degranulation and ROS production, we stimulated neutrophils, either with ssRNA and TNF or granulocyte-macrophage colony-stimulating factor and N-Formylmethionyl-leucyl-phenylalanine. During active COVID-19, neutrophils from hospitalized patients were more immature than from HDs and were impaired in degranulation and ROS generation, while neutrophils from nonhospitalized patients only demonstrated reduced CD66b+ granule release and ROS production. Baseline CD63 expression, indicative of primary granule release, and CXCL8 production by neutrophils from hospitalized patients were elevated for up to 6 months. These findings show that patients hospitalized due to COVID-19, but not nonhospitalized patients, demonstrated an aberrant neutrophil phenotype, degranulation, CXCL8 release, and ROS generation that partially persists up to 6 months after infection.

Sexual behaviour and incidence of sexually transmitted infections among men who have sex with men (MSM) using daily and event-driven pre-exposure prophylaxis (PrEP): Four-year follow-up of the Amsterdam PrEP (AMPrEP) demonstration project cohort.

BACKGROUND: An increasing number of countries are currently implementing or scaling-up HIV pre-exposure prophylaxis (PrEP) care. With the introduction of PrEP, there was apprehension that condom use would decline and sexually transmitted infections (STIs) would increase. To inform sexual health counselling and STI screening programmes, we aimed to study sexual behaviour and STI incidence among men who have sex with men (MSM) and transgender women who use long-term daily or event-driven PrEP. METHODS AND FINDINGS: The Amsterdam PrEP demonstration project (AMPrEP) was a prospective, closed cohort study, providing oral daily PrEP and event-driven PrEP to MSM and transgender women from 2015 to 2020. Participants could choose their PrEP regimen and could switch at each three-monthly visit. STI testing occurred at and, upon request, in-between 3-monthly study visits. We assessed changes in numbers of sex partners and condomless anal sex (CAS) acts with casual partners over time using negative binomial regression, adjusted for age. We assessed HIV incidence and changes in incidence rates (IRs) of any STI (i.e., chlamydia, gonorrhoea, or infectious syphilis) and individual STIs over time using Poisson regression, adjusted for age and testing frequency. A total of 367 participants (365 MSM) commenced PrEP and were followed for a median 3.9 years (interquartile range [IQR] = 3.4-4.0). Median age was 40 years (IQR = 32-48), 315 participants (85.8%) self-declared ethnicity as white and 280 (76.3%) had a university or university of applied sciences degree. Overall median number of sex partners (past 3 months) was 13 (IQR = 6-26) and decreased per additional year on PrEP (adjusted rate ratio [aRR] = 0.86/year, 95% confidence interval [CI] = 0.83-0.88). Overall median number of CAS acts with casual partners (past 3 months) was 10 (IQR = 3-20.5) and also decreased (aRR = 0.92/year, 95% CI = 0.88-0.97). We diagnosed any STI in 1,092 consultations during 1,258 person years, resulting in an IR of 87/100 person years (95% CI = 82-92). IRs of any STI did not increase over time for daily PrEP or event-driven PrEP users. Two daily PrEP users, and no event-driven PrEP users, were diagnosed with HIV during their first year on PrEP. Study limitations include censoring follow-up due to COVID-19 measures and an underrepresentation of younger, non-white, practically educated, and transgender individuals. CONCLUSIONS: In this prospective cohort with a comparatively long follow-up period of 4 years, we observed very low HIV incidence and decreases in the numbers of casual sex partners and CAS acts over time. Although the STI incidence was high, it did not increase over time. TRIAL REGISTRATION: The study was registered at the Netherlands Trial Register (NL5413) https://www.onderzoekmetmensen.nl/en/trial/22706.

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.

SARS-CoV-2 vaccination uptake in six ethnic groups living in Amsterdam, the Netherlands: A registry-based study within the HELIUS cohort.

OBJECTIVE: Ethnic minority groups have experienced a disproportionate burden of COVID-19, and should therefore be especially encouraged to receive SARS-CoV-2 vaccination. This study compared first-dose uptake of the primary SARS-CoV-2 vaccination series across six ethnic groups in Amsterdam, the Netherlands in 2021. METHODS: We analyzed data from participants of the population-based HELIUS cohort. We linked their data to the SARS-CoV-2 vaccination registry data of the Public Health Service of Amsterdam. We included registry data from January 6, 2021 (the start of the Dutch vaccination campaign) until September 6, 2021 (a date by which all adults in the Netherlands could have received one or two vaccine doses). SARS-CoV-2 vaccination uptake was defined as having received at least one vaccine dose of the primary vaccination series. We examined the association between ethnicity and vaccination uptake using multivariable logistic regression, while accounting for the age and sex distribution of ethnic groups in Amsterdam. RESULTS: We included 19,006 participants (median age 53 years [interquartile range 41-62], 57% female). SARS-CoV-2 vaccination uptake was highest in the South-Asian Surinamese group (60.3%, 95%CI = 58.2-62.3%), followed by the Dutch (59.6%, 95%CI = 58.0-61.1%), Ghanaian (54.1%, 95%CI = 51.7-56.5%), Turkish (47.7%, 95%CI = 45.9-49.6%), African Surinamese (43.0%, 95%CI = 41.2-44.7%), and Moroccan (35.8%, 95%CI = 34.1-37.5%) groups. After adjusting for age, sex, perceived social support, and presence of relevant comorbidities, participants of African Surinamese, Ghanaian, Turkish and Moroccan origin were significantly less likely to be vaccinated than those of Dutch origin. CONCLUSIONS: Prevention strategies should continue tailoring to specific ethnic groups to encourage vaccination uptake and reduce barriers to vaccination.

Efficacy of Cognitive-Behavioral Therapy Targeting Severe Fatigue Following Coronavirus Disease 2019: Results of a Randomized Controlled Trial.

BACKGROUND: Severe fatigue following coronavirus disease 2019 (COVID-19) is prevalent and debilitating. This study investigated the efficacy of cognitive-behavioral therapy (CBT) for severe fatigue following COVID-19. METHODS: A multicenter, 2-arm randomized controlled trial was conducted in the Netherlands with patients being severely fatigued 3-12 months following COVID-19. Patients (N = 114) were randomly assigned (1:1) to CBT or care as usual (CAU). CBT, targeting perpetuating factors of fatigue, was provided for 17 weeks. The primary outcome was the overall mean difference between CBT and CAU on the fatigue severity subscale of the Checklist Individual Strength, directly post-CBT or CAU (T1), and after 6 months (T2). Secondary outcomes were differences in proportions of patients meeting criteria for severe and/or chronic fatigue, differences in physical and social functioning, somatic symptoms, and problems concentrating between CBT and CAU. RESULTS: Patients were mainly nonhospitalized and self-referred. Patients who received CBT were significantly less severely fatigued across follow-up assessments than patients receiving CAU (-8.8 [95% confidence interval {CI}, -11.9 to -5.8]); P < .001), representing a medium Cohen's d effect size (0.69). The between-group difference in fatigue severity was present at T1 (-9.3 [95% CI, -13.3 to -5.3]) and T2 (-8.4 [95% CI, -13.1 to -3.7]). All secondary outcomes favored CBT. Eight adverse events were recorded during CBT, and 20 during CAU. No serious adverse events were recorded. CONCLUSIONS: Among patients, who were mainly nonhospitalized and self-referred, CBT was effective in reducing fatigue. The positive effect was sustained at 6-month follow-up. CLINICAL TRIALS REGISTRATION: Netherlands Trial Register NL8947.

The impact of COVID-19-related restrictions in 2020 on sexual healthcare use, pre-exposure prophylaxis use, and sexually transmitted infection incidence among men who have sex with men in Amsterdam, the Netherlands.

OBJECTIVES: We studied the effects of restrictions related to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2; coronavirus disease 2019 [COVID-19]) pandemic on the use of sexual healthcare and pre-exposure prophylaxis (PrEP) and on the incidence of sexually transmitted infections (STIs) among men who have sex with men (MSM) in a prospective, open-label PrEP demonstration study (AMPrEP) in Amsterdam, the Netherlands. METHODS: We retrieved data from 2019 to 2020 for participants with one or more study visit in 2019 (n = 305) and from two COVID-19 questionnaires (2020: n = 203; 2021: n = 160). Analyses were stratified for three periods of pandemic-related restrictions (first: 15 March 2020-15 June 2020; second: 16 June 2020-15 September 2020; third: 16 September 2020-31 December 2020 or 1 April 2021 for the COVID-19 questionnaire). Endpoints included returning for care during the pandemic, PrEP use (increased/unchanged vs. deceased/stopped, relative to 2019), and any STI/HIV. We modelled determinants of care and PrEP use via multivariable logistic regression and STI incidence using piecewise Poisson regression, comparing the 2020 and 2019 periods. RESULTS: Of the 305 MSM included in the analysis, 72.8% returned for care during the pandemic, and this was significantly more likely among daily (vs. event-driven) PrEP users (p < 0.001). Increased/unchanged PrEP use ranged from 55.2% to 58.1% across the three pandemic periods and was more likely among those reporting chemsex in the first (p = 0.001) and third (p = 0.020) periods and among those reporting an increased/unchanged number of sex partners during the second period (p = 0.010). STI incidence was significantly lower in 2020 than in 2019 during the first period (incidence rate ratio [IRR] 0.43; 95% confidence interval [CI] 0.28-0.68) and not significantly different during the second (IRR 1.38; 95% CI 0.95-2.00) and third (IRR 1.42; 95% CI 0.86-2.33) periods. No HIV was diagnosed. CONCLUSION: COVID-19-related restrictions coincided with reduced care and PrEP use. Changes in STI incidence suggest delayed diagnoses. Ways to ensure continued access to sexual healthcare during restrictions are needed.

Can we screen less frequently for STI among PrEP users? Assessing the effect of biannual STI screening on timing of diagnosis and transmission risk in the AMPrEP Study.

BACKGROUND: In many countries, HIV pre-exposure prophylaxis (PrEP) users are screened quarterly for STIs. We assessed the consequences of less frequent STI testing. We also assessed determinants of asymptomatic STI and potential for onward transmission. METHODS: Using data from the AMPrEP study, we assessed the proportion of syphilis, and genital, anal, and pharyngeal chlamydia and gonorrhoea diagnoses which would have been delayed with biannual versus quarterly screening. We assessed the potential for onward transmission by examining reported condomless anal sex (CAS) in periods after to-be-omitted visits when screening biannually. We assessed determinants of incident asymptomatic STIs using Poisson regression and calculated individual risk scores on the basis of the coefficients from this model. RESULTS: We included 366 participants. Median follow-up was 47 months (IQR 43-50). 1,183STIs were diagnosed, of which 932(79%) asymptomatic. With biannual screening, 483 asymptomatic STIs (52%) diagnoses would have been delayed at 364 study visits. Of these visits, 129 (35%), 240 (66%) and 265 (73%) were followed by periods of CAS with steady, known casual or unknown casual partners, respectively. Older participants had a lower risk of asymptomatic STI (incidence rate ratio (IRR) 0.86/10-year increase, 95% CI 0.80 to 0.92), while CAS with known (IRR 1.36, 95% CI 1.10 to 1.68) and unknown (IRR 1.86, 95% CI 1.48 to 2.34) casual partners and chemsex (IRR 1.51, 95% CI 1.28 to 1.78) increased the risk. The individual risk scores had limited predictive value (sensitivity=0.70 (95% CI 0.66 to 0.74), specificity=0.50 (95% CI 0.48 to 0.51)). CONCLUSION: Reducing the STI screening frequency to biannually among PrEP users will likely result in delayed diagnoses, potentially driving onward transmission. Although determinants for asymptomatic STIs were identified, predictive power was low.

Determinants of adherence to daily PrEP measured as intracellular tenofovir diphosphate concentrations over 24 months of follow-up among men who have sex with men.

OBJECTIVES: Adherence is key to the effectiveness of oral pre-exposure prophylaxis (PrEP) to prevent HIV. Therefore, we aimed to explore factors associated with adherence to daily PrEP (dPrEP). METHODS: Men who have sex with men (MSM) using dPrEP (emtricitabine/tenofovir disoproxil) within the Amsterdam PrEP demonstration project at the Public Health Service of Amsterdam, provided dried blood spots (DBS) 12 and 24 months after PrEP initiation. From DBS, we determined intracellular tenofovir diphosphate (TFV-DP) concentrations to assess adherence; TFV-DP ≥700 fmol/punch was considered adequate. We assessed associations of sociodemographic, clinical and behavioural characteristics with TFV-DP concentrations using multivariable linear regression. RESULTS: Of 263 participants who attended 12-month or 24-month study visits while on dPrEP, 257 (97.7%) provided DBS at one or both visits (492 DBS in total). Median TFV-DP concentration was 1299 (IQR 1021-1627) fmol/punch (12 months: 1332 (1087-1687); 24 months: 1248 (929-1590]). Higher TFV-DP concentrations were associated with: older age (p=0.0008), condomless anal sex with a casual partner in 6 months preceding PrEP initiation (+166 fmol/punch; 95% CI 36.5 to 296) and using a mobile application providing visualised feedback on PrEP use and sexual behaviour (+146 fmol/punch; 95% CI 28.1 to 263). Lower TFV-DP concentrations were associated with longer duration of PrEP use (24 vs 12 months; -91.5 fmol/punch; 95% CI -155 to -28.1). Time-updated number of sex partners, diagnosed STIs and chemsex were not associated with TFV-DP concentrations. CONCLUSIONS: Overall, TFV-DP concentrations were high among MSM using dPrEP, indicating excellent adherence. Especially older participants, those who reported condomless anal sex with a casual partner prior to PrEP initiation and those who used an app with visualised feedback showed higher levels of adherence. As TFV-DP concentrations had decreased slightly at 2 years of PrEP use when compared with 1 year, we emphasise the importance of adherence counselling to those who continue using PrEP. TRIAL REGISTRATION NUMBER: NL5413.

Relative contributions of pre-pandemic factors and intra-pandemic activities to differential COVID-19 risk among migrant and non-migrant populations in the Netherlands: lessons for future pandemic preparedness.

BACKGROUND: Although risk factors for differences in SARS-CoV-2 infections between migrant and non-migrant populations in high income countries have been identified, their relative contributions to these SARS-CoV-2 infections, which could aid in the preparation for future viral pandemics, remain unknown. We investigated the relative contributions of pre-pandemic factors and intra-pandemic activities to differential SARS-CoV-2 infections in the Netherlands by migration background (Dutch, African Surinamese, South-Asian Surinamese, Ghanaians, Turkish, and Moroccan origin). METHODS: We utilized pre-pandemic (2011-2015) and intra-pandemic (2020-2021) data from the HELIUS cohort, linked to SARS-CoV-2 PCR test results from Public Health Service of Amsterdam (GGD Amsterdam). Pre-pandemic factors included socio-demographic, medical, and lifestyle factors. Intra-pandemic activities included COVID-19 risk aggravating and mitigating activities such as physical distancing, use of face masks, and other similar activities. We calculated prevalence ratios (PRs) in the HELIUS population that was merged with GGD Amsterdam PCR test data using robust Poisson regression (SARS-CoV-2 PCR test result as outcome, migration background as predictor). We then obtained the distribution of migrant and non-migrant populations in Amsterdam as of January 2021 from Statistics Netherlands. The migrant populations included people who have migrated themselves as well as their offspring. We used PRs and the population distributions to calculate population attributable fractions (PAFs) using the standard formula. We used age and sex adjusted models to introduce pre-pandemic factors and intra-pandemic activities, noting the relative changes in PAFs. RESULTS: From 20,359 eligible HELIUS participants, 8,595 were linked to GGD Amsterdam PCR test data and included in the study. Pre-pandemic socio-demographic factors (especially education, occupation, and household size) resulted in the largest changes in PAFs when introduced in age and sex adjusted models (up to 45%), followed by pre-pandemic lifestyle factors (up to 23%, especially alcohol consumption). Intra-pandemic activities resulted in the least changes in PAFs when introduced in age and sex adjusted models (up to 16%). CONCLUSION: Interventions that target pre-pandemic socio-economic status and other drivers of health inequalities between migrant and non-migrant populations are urgently needed at present to better prevent infection disparities in future viral pandemics.

Substantial impact of the COVID-19 pandemic on the reported number of diagnosed chronic hepatitis C virus infections in the Netherlands, 2019-2021.

BACKGROUND: The COVID-19 pandemic has widespread consequences for health facilities, social contacts, and health-seeking behaviour, affecting the incidence, diagnosis and reporting of other infectious diseases. We examined trends in reported chronic hepatitis C virus (HCV) infections and associated transmission routes in the Netherlands to identify the potential impact of COVID-19 on access to healthcare (testing) services. METHODS: We analysed notification data of patients with chronic HCV reported to the National Notifiable Disease Surveillance System from January 2019 until December 2021 in the Netherlands. Rates of newly reported chronic cases per 100,000 population with 95% confidence intervals (CI) were calculated, and we compared proportional changes in transmission routes for chronic HCV between 2019, 2020 and 2021. RESULTS: During the study period, a total of 1,521 chronic HCV infections were reported, 72% males, median age 52 years, and an overall rate of 8.8 (95%CI 8.4-9.2) per 100,000 population. We observed an overall decline (-41.9%) in the number of reported chronic HCV in 2020 compared to 2019, with the sharpest decline in men who have sex with men (MSM)-related transmission (-57.9% in 2020, p = 0.005). CONCLUSIONS: Reported cases of chronic HCV strongly declined during the COVID-19 pandemic when healthcare services were scaled down. Between February and June 2021, reported chronic HCV cases increased again, indicating a recovery of healthcare services. MSM showed the largest decline compared to other groups. Further research is needed to fully understand the impact of access to healthcare, health seeking behaviour, and (sexual) transmission risks of HCV during the COVID-19 pandemic.

Dengue, chikungunya and Zika virus infections among Dutch travellers to Suriname: a prospective study during the introduction of chikungunya and Zika virus, 2014 to 2017.

BackgroundSuriname, a country endemic for dengue virus (DENV), is a popular destination for Dutch travellers visiting friends and relatives and tourist travellers. Chikungunya and Zika virus (CHIKV, ZIKV) were introduced in 2014 and 2015, respectively. Data on infection risks among travellers are limited.AimWe aimed to prospectively study incidence rate (IR) and determinants for DENV, ZIKV and CHIKV infection in adult travellers to Suriname from 2014 through 2017.MethodsParticipants kept a travel diary and were tested for anti-DENV, anti-ZIKV and anti-CHIKV IgG antibodies (Euroimmun). Selected samples were subjected to an in-house DENV and ZIKV PRNT50. The IR (infections/1,000 person-months of travel) and IR ratio and determinants for infection were calculated.ResultsTravel-acquired infections were found in 21 of 481 participants: 18 DENV, four ZIKV and two CHIKV, yielding an IRDENV of 47.0 (95% CI: 29.6-74.6), IRZIKV of 11.6 (95% CI: 4.4-31.0) and IRCHIKV of 5.6 (95% CI: 1.4-22.2)/1,000 person-months. In nine DENV and three ZIKV infected participants, infections were PRNT50-confirmed, yielding a lower IRDENV of 23.3 (95% CI: 12.1-44.8) and an IRZIKV of 8.4 (95% CI: 2.7-26.1) per 1,000 person-months. Tourist travel was associated with DENV infection. ZIKV and CHIKV infections occurred soon after their reported introductions.ConclusionsDespite an overestimation of serologically confirmed infections, Dutch travellers to Suriname, especially tourists, are at substantial risk of DENV infection. As expected, the risk of contracting ZIKV and CHIKV was highest during outbreaks. Cross-reaction and potential cross-protection of anti-DENV and -ZIKV antibodies should be further explored.

Mpox outbreak among men who have sex with men in Amsterdam and Rotterdam, the Netherlands: no evidence for undetected transmission prior to May 2022, a retrospective study.

Since May 2022, over 21,000 mpox cases have been reported from 29 EU/EEA countries, predominantly among men who have sex with men (MSM). The Netherlands was the fourth most affected country in Europe, with more than 1,200 cases and a crude notification rate of 70.7 per million population. The first national case was reported on 10 May, yet potential prior transmission remains unknown. Insight into prolonged undetected transmission can help to understand the current outbreak dynamics and aid future public health interventions. We performed a retrospective study and phylogenetic analysis to elucidate whether undetected transmission of human mpox virus (hMPXV) occurred before the first reported cases in Amsterdam and Rotterdam. In 401 anorectal and ulcer samples from visitors to centres for sexual health in Amsterdam or Rotterdam dating back to 14 February 2022, we identified two new cases, the earliest from 6 May. This coincides with the first cases reported in the United Kingdom, Spain and Portugal. We found no evidence of widespread hMPXV transmission in Dutch sexual networks of MSM before May 2022. Likely, the mpox outbreak expanded across Europe within a short period in the spring of 2022 through an international highly intertwined network of sexually active MSM.

Evolution of Coronavirus Disease 2019 (COVID-19) Symptoms During the First 12 Months After Illness Onset.

BACKGROUND: Few robust longitudinal data on long-term coronavirus disease 2019 (COVID-19) symptoms are available. We evaluated symptom onset, severity and recovery across the full spectrum of disease severity, up to one year after illness onset. METHODS: The RECoVERED Study is a prospective cohort study based in Amsterdam, the Netherlands. Participants aged ≥18 years were enrolled following severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) diagnosis via the local public health service and from hospitals. Standardized symptom questionnaires were completed at enrollment, 1 week and month later, and monthly thereafter. Clinical severity was defined according to World Health Organization (WHO) criteria. Kaplan-Meier methods were used to compare time from illness onset to symptom recovery, by clinical severity. We examined determinants of time to recovery using multivariable Cox proportional hazards models. RESULTS: Between 11 May 2020 and 1 May 2021, 342 COVID-19 patients (192 [56%] male) were enrolled, of whom 99/342 (29%) had mild, 145/342 (42%) moderate, 56/342 (16%) severe, and 42/342 (12%) critical disease. The proportion of participants who reported at least 1 persistent symptom at 12 weeks after illness onset was greater in those with severe/critical disease (86.7% [95% confidence interval {CI} = 76.5-92.7%]) compared to those with mild or moderate disease (30.7% [95% CI = 21.1-40.9%] and 63.8% [95% CI = 54.8-71.5%], respectively). At 12 months after illness onset, two-fifths of participants (40.7% [95% CI = 34.2-7.1]) continued to report ≥1 symptom. Recovery was slower in female compared to male participants (adjusted hazard ratio [aHR] 0.65 [95% CI = .47-.92]) and those with a body mass index [BMI]  ≥30kg/m2 compared to BMI <25kg/m2 (hazard ratio [HR] 0.62 [95% CI = .39-.97]). CONCLUSIONS: COVID-19 symptoms persisted for one year after illness onset, even in some individuals with mild disease. Female sex and obesity were the most important determinants of speed of recovery from symptoms.

Antibody responses against SARS-CoV-2 variants induced by four different SARS-CoV-2 vaccines in health care workers in the Netherlands: A prospective cohort study.

BACKGROUND: Emerging and future SARS-CoV-2 variants may jeopardize the effectiveness of vaccination campaigns. Therefore, it is important to know how the different vaccines perform against diverse SARS-CoV-2 variants. METHODS AND FINDINGS: In a prospective cohort of 165 SARS-CoV-2 naive health care workers in the Netherlands, vaccinated with either one of four vaccines (BNT162b2, mRNA-1273, AZD1222 or Ad26.COV2.S), we performed a head-to-head comparison of the ability of sera to recognize and neutralize SARS-CoV-2 variants of concern (VOCs; Alpha, Beta, Gamma, Delta and Omicron). Repeated serum sampling was performed 5 times during a year (from January 2021 till January 2022), including before and after booster vaccination with BNT162b2. Four weeks after completing the initial vaccination series, SARS-CoV-2 wild-type neutralizing antibody titers were highest in recipients of mRNA-1273, followed by recipients of BNT162b2 (geometric mean titers (GMT) of 358 [95% CI 231-556] and 214 [95% CI 153-299], respectively; p<0.05), and substantially lower in those vaccinated with the adenovirus vector-based vaccines AZD1222 and Ad26.COV2.S (GMT of 18 [95% CI 11-30] and 14 [95% CI 8-25] IU/ml, respectively; p<0.001). VOCs neutralization was reduced in all vaccine groups, with the greatest reduction in neutralization GMT observed against the Omicron variant (fold change 0.03 [95% CI 0.02-0.04], p<0.001). The booster BNT162b2 vaccination increased neutralizing antibody titers for all groups with substantial improvement against the VOCs including the Omicron variant. We used linear regression and linear mixed model analysis. All results were adjusted for possible confounding of age and sex. Study limitations include the lack of cellular immunity data. CONCLUSIONS: Overall, this study shows that the mRNA vaccines appear superior to adenovirus vector-based vaccines in inducing neutralizing antibodies against VOCs four weeks after initial vaccination and after booster vaccination, which implies the use of mRNA vaccines for both initial and booster vaccination.

Health-related quality of life among persons with initial mild, moderate, and severe or critical COVID-19 at 1 and 12 months after infection: a prospective cohort study.

BACKGROUND: Currently, there is limited evidence about the long-term impact on physical, social and emotional functioning, i.e. health-related quality of life (HRQL) after mild or moderate COVID-19 not requiring hospitalization. We compared HRQL among persons with initial mild, moderate or severe/critical COVID-19 at 1 and 12 months following illness onset with Dutch population norms and investigated the impact of restrictive public health control measures on HRQL. METHODS: RECoVERED, a prospective cohort study in Amsterdam, the Netherlands, enrolled adult participants after confirmed SARS-CoV-2 diagnosis. HRQL was assessed with the Medical Outcomes Study Short Form 36-item health survey (SF-36). SF-36 scores were converted to standard scores based on an age- and sex-matched representative reference sample of the Dutch population. Differences in HRQL over time were compared among persons with initial mild, moderate or severe/critical COVID-19 using mixed linear models adjusted for potential confounders. RESULTS: By December 2021, 349 persons were enrolled of whom 269 completed at least one SF-36 form (77%). One month after illness onset, HRQL was significantly below population norms on all SF-36 domains except general health and bodily pain among persons with mild COVID-19. After 12 months, persons with mild COVID-19 had HRQL within population norms, whereas persons with moderate or severe/critical COVID-19 had HRQL below population norms on more than half of the SF-36 domains. Dutch-origin participants had significantly better HRQL than participants with a migration background. Participants with three or more COVID-19 high-risk comorbidities had worse HRQL than part participants with fewer comorbidities. Participants who completed the SF-36 when restrictive public health control measures applied reported less limitations in social and physical functioning and less impaired mental health than participants who completed the SF-36 when no restrictive measures applied. CONCLUSIONS: Twelve months after illness onset, persons with initial mild COVID-19 had HRQL within population norms, whereas persons with initial moderate or severe/critical COVID-19 still had impaired HRQL. Having a migration background and a higher number of COVID-19 high-risk comorbidities were associated with worse HRQL. Interestingly, HRQL was less impaired during periods when restrictive public health control measures were in place compared to periods without.

Stopping and restarting PrEP and loss to follow-up among PrEP-taking men who have sex with men and transgender women at risk of HIV-1 participating in a prospective cohort study in Kenya.

OBJECTIVE: To assess frequency and predictors of switching between being on and off PrEP and being lost to follow-up (LTFU) among men who have sex with men (MSM) and transgender women (TGW) with access to PrEP services in Sub-Saharan Africa. METHODS: This was a prospective cohort study of MSM and TGW from coastal Kenya who initiated daily oral PrEP from June 2017 to June 2019. Participants were followed monthly for HIV-1 testing, PrEP refill, risk assessment and risk reduction counselling. Follow-up was censored at the last visit before 30 June 2019, or the last HIV-1-negative visit (for those with HIV-1 seroconversion), whichever occurred first. We estimated transition intensities (TI) and predictors of switching: (i) between being off and on PrEP; and (ii) from either PrEP state and being LTFU (i.e. not returning to the clinic for > 90 days) using a multi-state Markov model. RESULTS: In all, 134 participants starting PrEP were followed for a median of 20.3 months [interquartile range (IQR): 7.7-22.1]. A total of 49 (36.6%) people stopped PrEP 73 times [TI = 0.6/person-year (PY), 95% confidence interval (CI): 0.5-0.7] and, of these, 25 (51.0%) restarted PrEP 38 times (TI = 1.2/PY, 95% CI: 0.9-1.7). In multivariable analysis, stopping PrEP was related to anal sex ≤ 3 months, substance-use disorder and travelling. Restarting PrEP was related to non-Christian or non-Muslim religion and travelling. A total of 54 participants were LTFU: on PrEP (n = 47, TI = 0.3/PY, 95% CI: 0.3-0.5) and off PrEP (n = 7, TI = 0.2/PY, 95% CI: 0.1-0.4). In multivariable analysis, becoming LTFU while on PrEP was associated with secondary education or higher, living in the area for ≤ 1 year, residence outside the immediate clinic area and alcohol-use disorder. CONCLUSIONS: Switching between being on and off PrEP or becoming LTFU while on PrEP was frequent among individuals at risk of HIV-1 acquisition. Alternative PrEP options (e.g. event-driven PrEP) may need to be considered for MSM and TGW with PrEP-taking challenges, while improved engagement with care is needed for all MSM and TGW regardless of PrEP regimen.

Internet-guided HCV-RNA testing: A promising tool to achieve hepatitis C micro-elimination among men who have sex with men.

In the Netherlands, hepatitis C virus (HCV) transmission occurs primarily in men who have sex with men (MSM). By early diagnosis and immediate treatment of acute HCV infections, HCV micro-elimination in MSM is within reach. In cooperation with the community affected, we developed an online HCV-RNA home-based self-sampling test service. This service combined online HCV self-risk assessment with the possibility to test anonymously for HCV-RNA. The service was available in the Netherlands from February 2018 till December 2020 and was promoted online on various dating sites and offline by community volunteers. Using website user data, test results and an online post-test user survey, we evaluated the service and user experiences. The website page with information about testing was visited by 3401 unique users, of whom 2250 used the HCV-risk assessment tool, 152 individuals purchased 194 HCV-RNA tests, and 104 tests were used, of which 101 gave a conclusive result. The target population of MSM at risk was successfully reached with 44.1% of users receiving the advice to test. The test service had a satisfactory uptake (6.8%, 152/2250), a very high HCV-RNA positivity rate (10.9%, 11/101) and was considered acceptable and easy to use by most MSM. We demonstrate that an HCV-RNA home-based self-sampling test service is successful in diagnosing HCV infections among MSM. This service could be a valuable addition to existing sexual healthcare services as it may reach men who are otherwise not tested.

HIV and STI positivity rates among transgender people attending two large STI clinics in the Netherlands.

BACKGROUND: Global data show that transgender people (TGP) are disproportionally affected by HIV and sexually transmitted infections (STIs); however, data are scarce for Western European countries. We assessed gender identities, sexual behaviour, HIV prevalence and STI positivity rates, and compared these outcomes between TGP who reported sex work and those who did not. METHODS: We retrospectively retrieved data from all TGP who were tested at the STI clinics of Amsterdam and The Hague, the Netherlands in 2017-2018. To identify one's gender identity, a 'two-step' methodology was used assessing, first, the assigned gender at birth (assigned male at birth (AMAB)) or assigned female at birth), and second, clients were asked to select one gender identity that currently applies: (1) transgender man/transgender woman, (2) man and woman, (3) neither man nor woman, (4) other and (5) not known yet. HIV prevalence, bacterial STI (chlamydia, gonorrhoea and/or infectious syphilis) positivity rates and sexual behaviour were studied using descriptive statistics. RESULTS: TGP reported all five categories of gender identities. In total 273 transgender people assigned male at birth (TGP-AMAB) (83.0%) and 56 transgender people assigned female at birth (TGP-AFAB) (17.0%) attended the STI clinics. Of TGP-AMAB, 14,6% (39/267, 95% CI 10.6% to 19.4%) were HIV-positive, including two new diagnoses and bacterial STI positivity was 15.0% (40/267, 95% CI 10.9% to 19.8%). Among TGP-AFAB, bacterial STI positivity was 5.6% (3/54, 95% CI 1.2% to 15.4%) and none were HIV-positive. Sex work in the past 6 months was reported by 53.3% (137/257, 95% CI 47.0% to 59.5%) of TGP-AMAB and 6.1% (3/49, 95% CI 1.3% to 16.9%) of TGP-AFAB. HIV prevalence did not differ between sex workers and non-sex workers. CONCLUSION: Of all TGP, the majority were TGP-AMAB of whom more than half engaged in sex work. HIV prevalence and STI positivity rates were substantial among TGP-AMAB and much lower among TGP-AFAB. Studies should be performed to provide insight into whether the larger population of TGP-AMAB and TGP-AFAB are at risk of HIV and STI.