The August 2020 COVID-19 outbreak in Aotearoa, New Zealand: Delayed contact tracing for Pacific people contributes to widening health disparities.

Background: After COVID-19 arrived in New Zealand, a national system was developed to improve the efficiency of contact tracing. The first outbreak was followed by a period of 'COVID-19 elimination', until a community outbreak occurred in August 2020. We describe the characteristics of cases and their contacts during this outbreak, focused on the results of contact tracing. Methods: COVID-19 case data from the national surveillance database were linked to contacts from the national contact tracing database. Demographic and clinical characteristics of cases, number of contacts, and timeliness of contact tracing were analysed by ethnicity. Findings: Most of the 179 cases were Pacific people (59%) or Maori (25%), living in areas of high socioeconomic deprivation, who had higher rates of comorbidity and accounted for almost all (21/22) hospitalisations, all 8 ICU admissions and all 3 deaths. Only 6% belonged to the European majority ethnic group. Of 2,528 registered contacts, 46% were Pacific, 14% Maori and 19% European. Only contacts that were reached were registered. Overall, 41% of contacts were reached within 4 days of onset of disease of the case, which was significantly lower for Pacific (31%) than for other ethnic groups. Interpretation: Our findings confirm the greater health burden that ethnic minorities face from COVID-19. The significant delay in the timeliness of care for Pacific people shows that the public health response was inequitable for those at highest risk. Tailored public health responses and better registration of marginalised groups are necessary to provide better access to services and to improve insights for optimal future outbreak management.

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.

Frequent delayed spontaneous seroclearance of hepatitis B virus after incident HBV infection among adult high-risk groups.

High rates (~25%) of developing chronic hepatitis B virus (HBV) infection (hepatitis B surface antigen (HBsAg)-positive for > 6 months following infection) have been observed in people who use drugs (PWUD) and men who have sex with men (MSM). We aimed to estimate the frequency of delayed HBsAg seroclearance, along with its determinants, and time to delayed HBsAg seroclearance. Data were used from MSM and PWUD enrolled in the Amsterdam Cohort Studies (1985-2002) who had anti-hepatitis B core antibody seroconversion. Potential determinants for standard HBsAg seroclearance, delayed HBsAg seroclearance and chronic HBV were examined using multinominal logistic regression. Time to HBsAg seroclearance was estimated using Kaplan-Meier curves. A total of 147 incident HBV infections occurred during follow-up. On initial HBsAg testing after infection (6-12 months), 42 (29%) were HBsAg-positive and 105 (71%) were HBsAg-negative ('standard HBsAg seroclearance'). Of the 42 initially HBsAg-positive individuals, 22 subsequently tested HBsAg-negative (of whom 7 (31.8%) were HBV DNA positive at last visit, suggesting occult HBV). Overall, 15 became HBsAg-negative and HBV DNA-negative ('delayed HBsAg seroclearance'), while 27 remained HBsAg and/or HBV DNA-positive ('chronic HBV'). The 5-year cumulative probability of delayed HBsAg seroclearance was 41.6% for initially HBsAg-positive individuals. Delayed HBsAg seroclearance and remaining chronically infected were associated with younger age and HIV/hepatitis C virus (HCV)-co-infection. In conclusion, delayed HBsAg seroclearance is common in these key adult populations at-risk for HBV, while proportion developing HBV chronicity (18%) is still higher compared to the general population (~5%). Given the proportion of individuals with occult HBV infection and that HCV direct-acting antivirals can lead to HBV reactivation, HBV DNA testing in HCV co-infected MSM/PWUD are warranted prior to treatment initiation.

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.

Men who have sex with men more often chose daily than event-driven use of pre-exposure prophylaxis: baseline analysis of a demonstration study in Amsterdam.

INTRODUCTION: The Amsterdam PrEP project is a prospective, open-label demonstration study at a large sexually transmitted infection (STI) clinic. We examined the uptake of PrEP; the baseline characteristics of men who have sex with men (MSM) and transgender persons initiating PrEP; their choices of daily versus event-driven PrEP and the determinants of these choices. METHODS: From August 2015 through May 2016, enrolment took place at the STI clinic of the Public Health Service of Amsterdam, the Netherlands. MSM or transgender persons were eligible if they had at least one risk factor for HIV infection within the preceding six months. Participants were offered a choice between daily or event-driven use of tenofovir/emtricitabine. Baseline data were analysed using descriptive statistics and multivariable analysis was employed to determine variables associated with daily versus event-driven PrEP. RESULTS: Online applications were submitted by 870 persons, of whom 587 were invited for a screening visit. Of them, 415 were screened for eligibility and 376 initiated PrEP. One quarter (103/376, 27%) chose event-driven PrEP. Prevalence of bacterial STI was 19.0% and mean condomless anal sex (CAS) episodes in the preceding three months were 11. In multivariable analysis, older age (≥45 vs. ≤34, aOR 2.1, 95% CI 1.2 to 3.9), being involved in a steady relationship (aOR 1.7, 95% CI 1.0 to 2.7), no other daily medication use (aOR 0.6, 95% CI 0.3 to 0.9), and fewer episodes of CAS (per log increase aOR 0.7, 95% CI 0.6 to 0.9) were determinants for choosing event-driven PrEP. DISCUSSION: PrEP programmes are becoming one of the more important intervention strategies with the goal of reducing incident HIV-infection and we were unable to accommodate many of the persons applying for this study. Offering a choice of dosing regimen to PrEP users may enable further personalization of HIV prevention strategies and enhance up-take, adherence and cost-effectiveness. CONCLUSIONS: The majority of participants preferred daily versus event-driven use. Within this majority, a high number of CAS episodes before PrEP initiation was reported and we observed a high prevalence of STI. Determinants of choosing event-driven PrEP were older age, fewer CAS episodes, no other daily medication use, and involved in a steady relationship.

Integrating hepatitis B, hepatitis C and HIV screening into tuberculosis entry screening for migrants in the Netherlands, 2013 to 2015.

We evaluated uptake and diagnostic outcomes of voluntary hepatitis B (HBV) and C virus (HCV) screening offered during routine tuberculosis entry screening to migrants in Gelderland and Amsterdam, the Netherlands, between 2013 and 2015. In Amsterdam, HIV screening was also offered. Overall, 54% (461/859) accepted screening. Prevalence of chronic HBV infection (HBsAg-positive) and HCV exposure (anti-HCV-positive) in Gelderland was 4.48% (9/201; 95% confidence interval (CI): 2.37-8.29) and 0.99% (2/203; 95% CI: 0.27-3.52), respectively, all infections were newly diagnosed. Prevalence of chronic HBV infection, HCV exposure and chronic HCV infection (HCV RNA-positive) in Amsterdam was 0.39% (1/256; 95% CI: 0.07-2.18), 1.17% (3/256; 95% CI: 0.40-3.39) and 0.39% (1/256; 95% CI: 0.07-2.18), respectively, with all chronic HBV/HCV infections previously diagnosed. No HIV infections were found. In univariate analyses, newly diagnosed chronic HBV infection was more likely in participants migrating for reasons other than work or study (4.35% vs 0.83%; odds ratio (OR) = 5.45; 95% CI: 1.12-26.60) and was less likely in participants in Amsterdam than Gelderland (0.00% vs 4.48%; OR = 0.04; 95% CI: 0.00-0.69). Regional differences in HBV prevalence might be explained by differences in the populations entering compulsory tuberculosis screening. Prescreening selection of migrants based on risk factors merits further exploration.

Hepatitis A outbreak among men who have sex with men (MSM) predominantly linked with the EuroPride, the Netherlands, July 2016 to February 2017.

Between July 2016 and February 2017, 48 male cases of hepatitis A were notified in the Netherlands. Of these, 17 identified as men who have sex with men (MSM). Ten of the 13 cases for whom sequencing information was available, were infected with a strain linked with the EuroPride that took place in Amsterdam in 2016. This strain is identical to a strain that has been causing a large outbreak among MSM in Taiwan.

Incidence, risk factors and treatment of diarrhoea among Dutch travellers: reasons not to routinely prescribe antibiotics.

BACKGROUND: Travellers' diarrhoea (TD) is the most common infectious disease among travellers. In the Netherlands, stand-by or prophylactic antibiotics are not routinely prescribed to travellers. This study prospectively assessed the incidence rate, risk factors, and treatment of TD among immunocompetent travellers. METHODS: Persons who attended the travel clinic of the Public Health Service Amsterdam in 2006-2007 before short-term travel to tropical and subtropical countries were invited to answer a questionnaire regarding sociodemographics and travel purpose; they were also asked to keep a daily structured travel diary, recording their itinerary, symptoms, and self-medication or consultation with a doctor. Diarrhoea episodes containing blood or mucous were considered severe. RESULTS: Of 1202 travellers, the median age was 38 years, and the median travel duration 3 weeks. Of all episodes, 96% were mild. The median duration of TD was 2 days and significantly shorter in subsequent episodes compared to first episodes (p < 0.0005). Of first episodes 38% started in the first travel week. The incidence rate (IR) for first episodes was 2.49 (95% confidence interval [CI], 2.30-2.70) per 100 travel days, with the highest IR among travellers to South-Central and West Asia. The IR for first and subsequent episodes was comparable. Risk factors for first episodes included female sex, a Western country of birth, and tourism as the purpose of travel. The lowest risk was in travellers to South America. An independent risk factor for subsequent episodes was female sex. In total, 5% of travellers used antibiotics; of those, 92% had mild diarrhoea, and 53% received antibiotics over the counter. CONCLUSIONS: TD is common among travellers, but the overall course is mild, not requiring treatment. The incidence rates for first and second episodes are comparable. Female sex is a risk factor for the first episode, as well as subsequent ones. Prescription antibiotics are not needed in short-term healthy travellers.