Excess mortality among native Belgians and migrant groups in Belgium during the first three COVID-19 waves: the evolving dynamics of social inequalities

Aim Research shows migrant groups have an increased risk of COVID-19 incidence, hospitalization and mortality. Much less is known about how these findings have developed throughout the different stages of the crisis. This study assesses patterns in excess mortality by migrant group during the first three COVID-19 waves in Belgium, while taking sociodemographic and socioeconomic indicators into account. Subject and methods Data were derived from an individual-level linkage between the Belgian National Register, the 2011 Belgian census and the tax register. The study population consisted of the legal Belgian population aged 40 years and older (N = 6,004,695). Age-standardized all-cause mortality rates were calculated for the first three COVID waves, and for the same weeks in 2019. Relative mortality differences were studied using Poisson regression. Analyses were stratified by age group, gender and wave. Results The heaviest mortality burden fell on the elderly male population, whose mortality patterns also diverged considerably from pre-pandemic times. The largest mortality differences with the Belgian population were observed for elderly Turkish men (> 26% in waves 1-3) and women (similar to 40% in wave 2-3), after controlling for sociodemographic and socioeconomic indicators. While in 2019 some migrant groups experienced a mortality advantage compared to their Belgian peers, this advantage was reduced or turned into a disadvantage during the COVID-crisis.Conclusion Significant mortality inequalities were found by migrant group, even after controlling for sociodemographic and socioeconomic background. Mortality patterns varied considerably throughout the three waves under investigation, possibly because of the dynamic nature of the epidemic and the uptake of preventative measures.