Excess mortality during the first and second waves of the COVID-19 epidemic in Belgium

COVID-19 mortality was highly correlated with excess all-cause mortality during the first two waves of the epidemic. Epidemiologic surveillance of COVID-19 deaths was accurately conducted during the epidemic and it is even likely that COVID-19 deaths were underreported during the ascending phases of excess mortality by 1,193 deaths. The first wave of the epidemic has a larger excess mortality than the second wave. People aged 85 and over were the most affected during the two periods of excess mortality. The year 2020 has a 17.5% excess mortality with 18,765 additional deaths, eight times the average excess mortality of the past five years. In the absence of the implementation of restrictive measures (e.g., social distancing, etc.) and non-pharmaceutical interventions (e.g., hand hygiene, personal protective equipment, etc.), it is possible that the excess mortality during this period would have been greater. Mortality analysis encompassing entire winter seasons is more accurate for flu, which often spreads over several winter months, spread over two calendar years. It provides very different results than a typical annual analysis from January to December. Even in the 21st century, epidemics of respiratory infectious diseases can be major lethal events of rapid onset in a susceptible and vulnerable population