Capturing excess cause‐specific mortality during the COVID‐19 pandemic in the Netherlands using an advanced multi‐state model with relative survival

We present a new framework to estimate excess cause‐specific mortality by integrating relative survival into a multi‐state model, motivated by the question of how vaccination and infection impacted different components of excess mortality for the older Dutch population during the first two years of the COVID‐19 pandemic in the Netherlands. The proportion of the study population who died from COVID‐19, 0.98%, was nearly three times the excess proportion of all‐cause mortality, 0.34%, reflecting a mortality substitution effect: other causes of death occurred less than expected. COVID‐19 infection increased short‐term mortality across all causes of death, with residual risk beyond 28 days postinfection. Vaccination was associated with reduced COVID‐19 mortality risk in both the acute and long‐term infection phases, with consistent results across landmark times. Results suggest a healthy vaccinee bias, specifically for cardiovascular diseases, mental & neurological disorders and neoplasms. However, this bias seems far smaller than the impact of vaccination on reduction of COVID‐19 mortality.