Background: During the first waves of the COVID-19 pandemic, SARS-CoV-2 antibody prevalence (seroprevalence) was lower in older compared to younger adults. We studied age group differences in SARS-CoV-2 seroprevalence, across ethnic groups, and assessed the explanatory value of factors that increase the exposure to the virus, and factors related to susceptibility, given the level of exposure.
Methods: We analysed cross-sectional data from 2,064 participants from the multi-ethnic HELIUS study (Amsterdam, The Netherlands). SARS-CoV-2 seroprevalence at the second wave of infections was compared between age groups (<40, 40-54, and ≥55 years), within ethnic groups, using Poisson regression with robust standard errors. To determine whether age group differences were explained by differences in exposure and in susceptibility, we sequentially adjusted for exposure (job setting, occupation level, health literacy, household size, household member with suspected infection), education level, and susceptibility (vitamin D intake, BMI, systolic blood pressure, haemoglobin level, number of comorbidities).
Results: SARS-CoV-2 seroprevalence did not statistically differ across age groups (p>0.05), but age patterns varied across ethnic groups. Age group differences in SARS-CoV-2 seroprevalence were most pronounced in the Dutch majority group, with the highest prevalence ratio in the youngest group (2.55, 95%CI 0.93-6.97) and the lowest in the oldest group (0.53, 95%CI 0.16-1.74), compared to the middle-aged group. In ethnic minority groups, age group differences were smaller. In all groups, patterns did not substantially change after adjustments for exposure and susceptibility variables.
Conclusion: We found no evidence of age group differences in SARS-CoV-2 seroprevalence, particularly for ethnic minority groups, even when accounting for exposure and susceptibility. While early prevention strategies particularly aimed at protecting older adults against SARS-CoV-2 infections, seroprevalence was similar across age groups in ethnic minority groups. Thus, older adults in ethnic minority groups may pose a target group for additional prevention strategies for future infectious disease outbreaks.
Copyright: © 2024 Bolijn et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.