October 6, 2020 Journal article Open Access

Influenza Vaccination Rates Predict 30% of the Variance in Covid-19 Related Deaths in Europe – A Modeling Approach

Walach, Harald; Klement, Rainer Johannes

There is a high variability in Covid-19 related deaths whose origin is unclear. We used
three variables, percent test-standardized number of SARS-CoV-2-cases in a country,
influenza-vaccination coverage in the elderly in a country and number of non-pharmaceutical
interventions, to predict the number of population standardized Covid-19 related deaths in
European countries, using generalized linear models. With these variables we can clarify
approximately 60% of the variation in Covid-19 related deaths, with flu-vaccination coverage
in the elderly being the most important predictor, explaining nearly 30% of the variation.
Thus, the higher the influenza vaccination coverage in the elderly in a country, the more
Covid-19 related deaths we see. Also, the more non-pharmaceutical interventions, the more
deaths are likely, explaining about 5% of the variation. Other variables, like life-expectancy,
rapidity of a country’s reaction to the epidemic and population size did not emerge as
significant predictors. Thus, contrary to current opinion, flu-vaccination in the elderly might
be an aggravating factor, when it comes to Covid-19 related deaths.