Covid-19 vaccination coverage by birth country and underlying risk for severe Covid-19 disease

Abstract Backround It is unknown whether differences in age and health profiles contribute to explain the observed variation in Covid-19 vaccination coverage between birth countries. If the unvaccinated are mostly young and healthy, the consequences for severe illness and healthcare capacity will be less than if the unvaccinated have underlying risk for severe Covid-19 disease. This study aims to investigate whether differences in Covid-19 vaccination coverage by birth country in Norway are equally prominent among individuals with underlying risk for a severe Covid-19 disease course. Methods With register data from the Norwegian Emergency Preparedness Register, we linked vaccination coverage to demographic and socioeconomic variables for all Norwegian residents. Using Poisson regression, we examined if demonstrated differences in vaccination coverage between countries of birth were as prominent among individuals with underlying risk factors for severe Covid-19 disease, controlled for gender, age, education level, household income, and county. Results The demonstrated variation in Covid-19 vaccination coverage between Norwegian-born and foreign-born is lower when we limit the study population to those with underlying risk factors. Among people without underlying risk, the incidence rate ratio for being vaccinated was lowest for people born in Poland (IRR = 0.55; 95% CI 0.55 to 0.56) and Lithuania (IRR = 0.61; 95% CI 0.6 to 0.62), but the greatest increase in IRR was found for people with underlying risk factors born in these countries. Conclusions The study illuminates two facets of the difference in vaccination coverage between Norwegian-born and foreign-born individuals. First, the difference in vaccination coverage was smaller within groups with underlying risk for severe Covid-19 outcomes than for groups without. Second, the differences in vaccination coverage by birth country remains, even constrained on individuals with underlying risk. Key messages • The observed differences in Covid-19 vaccination coverage by birth country are smaller within groups with underlying risk factors. • Foreign-born individuals are a heterogenous group, crucial in considering all health policy formulations.