Ethnic disparities in incident SARS-CoV-2 infections became wider during the second wave of SARS-CoV-2 in Amsterdam, the Netherlands: a population-based longitudinal study

BackgroundSurveillance data in high-income countries have reported more frequent SARS-CoV-2 diagnoses in ethnic minority groups. We examined the cumulative incidence of SARS-CoV-2 and its determinants in six ethnic groups in Amsterdam, the Netherlands. MethodsWe analyzed participants enrolled in the population-based HELIUS cohort, who were tested for SARS-CoV-2-specific antibodies and answered COVID-19-related questions between June 24-October 9, 2020 (after the first wave) and November 23, 2020-March 31, 2021 (during the second wave). We modeled SARS-CoV-2 incidence from January 1, 2020-March 31, 2021 using Markov models adjusted for age and sex. We compared incidence between ethnic groups over time and identified determinants of incident infection within ethnic groups. Findings2,497 participants were tested after the first wave; 2,083 (83{middle dot}4%) were tested during the second wave. Median age at first visit was 54 years (interquartile range=44-61); 56{middle dot}6% were female. Compared to Dutch-origin participants (15{middle dot}9%), cumulative SARS-CoV-2 incidence was higher in participants of South-Asian Surinamese (25{middle dot}0%; adjusted hazard ratio [aHR]=1{middle dot}66;95%CI=1{middle dot}16-2{middle dot}40), African Surinamese (28{middle dot}9%;aHR=1{middle dot}97;95%CI=1{middle dot}37-2{middle dot}83), Turkish (37{middle dot}0%;aHR=2{middle dot}67;95%CI=1{middle dot}89-3{middle dot}78), Moroccan (41{middle dot}9%;aHR=3{middle dot}13;95%CI=2{middle dot}22-4{middle dot}42), and Ghanaian (64{middle dot}6%;aHR=6{middle dot}00;95%CI=4{middle dot}33-8{middle dot}30) origin. Compared to those of Dutch origin, differences in incidence became wider during the second versus first wave for all ethnic minority groups (all p for interaction<0.05), except Ghanaians. Having household members with suspected SARS-CoV-2 infection, larger household size, and low health literacy were common determinants of SARS-CoV-2 incidence across groups. InterpretationSARS-CoV-2 incidence was higher in the largest ethnic minority groups of Amsterdam, particularly during the second wave. Prevention measures, including vaccination, should be encouraged in these groups. FundingZonMw, Public Health Service of Amsterdam, Dutch Heart Foundation, European Union, European Fund for the Integration of non-EU immigrants.

Hospitalisation rates differed by city district and ethnicity during the first wave of COVID-19 in Amsterdam, the Netherlands

BackgroundIt is important to gain insight into the burden of COVID-19 at city district level to develop targeted prevention strategies. We examined COVID-19 related hospitalisations by city district and migration background in the municipality of Amsterdam, the Netherlands. MethodsWe used surveillance data on all PCR-confirmed SARS-CoV-2 hospitalisations in Amsterdam until 31 May 2020, matched to municipal registration data on migration background. We calculated directly standardised (age, sex) rates (DSR) of hospitalisations, as a proxy of COVID-19 burden, per 100,000 population by city district and migration background. We calculated standardised rate differences (RD) and rate ratios (RR) to compare hospitalisations between city districts of varying socio-economic and health status and between migration backgrounds. We evaluated the effects of city district and migration background on hospitalisation after adjusting for age and sex using Poisson regression. ResultsBetween 29 February and 31 May 2020, 2326 cases (median age 57 years [IQR=37-74]) were notified in Amsterdam, of which 596 (25.6%) hospitalisations and 287 (12.3%) deaths. 526/596 (88.2%) hospitalisations could be matched to the registration database. DSR were higher in individuals living in peripheral (South-East/New-West/North) city districts with lower economic and health status, compared to central districts (Centre/West/South/East) (RD=36.87,95%CI=25.79-47.96;RR=1.82,95%CI=1.65-1.99), and among individuals with a non-Western migration background compared to ethnic-Dutch individuals (RD=57.05,95%CI=43.34-70.75; RR=2.36,95%CI=2.17-2.54). City district and migration background were independently associated with hospitalisation. ConclusionCity districts with lower economic and health status and those with a non-Western migration background had the highest burden of COVID-19 during the first wave of COVID-19 in Amsterdam.

SARS-CoV-2 antibody prevalence and determinants of six ethnic groups living in Amsterdam, the Netherlands: a population-based cross-sectional study, June-October 2020

BackgroundEthnic minorities have higher rates of SARS-CoV-2 diagnoses, but little is known about ethnic differences in past exposure. We aimed to determine whether prevalence and determinants of SARS-CoV-2 exposure varied between six ethnic groups in Amsterdam, the Netherlands. MethodsParticipants aged 25-79 years enrolled in a population-based prospective cohort were randomly selected within ethnic groups and invited to test for SARS-CoV-2-specific antibodies and answer COVID-19 related questions. We estimated prevalence and determinants of SARS-CoV-2 exposure within ethnic groups using survey-weighted logistic regression adjusting for age, sex and calendar time. ResultsBetween June 24-October 9, 2020, we included 2497 participants. Adjusted SARS-CoV-2 seroprevalence was comparable between ethnic-Dutch (25/498; 5.5%, 95%CI=3.2-7.9), South-Asian Surinamese (22/451; 4.8%, 95%CI=2.1-7.5), African Surinamese (22/400; 8.2%, 95%CI=3.0-13.4), Turkish (30/408; 7.8%, 95%CI=4.3-11.2) and Moroccan (32/391; 7.0%, 95%CI=4.0-9.9) participants, but higher among Ghanaians (95/327; 26.5%, 95%CI=18.7-34.4). 57.1% of SARS-CoV-2-positive participants did not suspect or were unsure of being infected, which was lowest in African Surinamese (18.2%) and highest in Ghanaians (90.5%). Determinants of SARS-CoV-2 exposure varied across ethnic groups, while the most common determinant was having a household member suspected of infection. In Ghanaians, seropositivity was associated with older age, larger household sizes, living with small children, leaving home to work and attending religious services. ConclusionsNo remarkable differences in SARS-CoV-2 seroprevalence were observed between the largest ethnic groups in Amsterdam after the first wave of infections. The higher infection seroprevalence observed among Ghanaians, which passed mostly unnoticed, warrants wider prevention efforts and opportunities for non-symptom-based testing.