Positive association between COVID-19 deaths and influenza vaccination rates in elderly people worldwide


By Christian Wehenkel

Instituto de Silvicultura e Industria de la Madera, Universidad Juárez del Estado de Durango,Durango, Mexico


Background: The coronavirus disease 2019 (COVID-19) pandemic, caused bysevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is an ongoing globalhealth crisis, directly and indirectly impacting all spheres of human life. Somepharmacological measures have been proposed to prevent COVID-19 or reduceits severity, such as vaccinations. Previous reports indicate that influenza vaccinationappears to be negatively correlated with COVID-19-associated mortality,perhaps as a result of heterologous immunity or changes in innate immunity.The understanding of such trends in correlations could prevent deaths fromCOVID-19 in the future. The aim of this study was therefore to analyze theassociation between COVID-19 related deaths and influenza vaccination rate (IVR)in elderly people worldwide.

Methods: To determine the association between COVID-19 deaths and influenzavaccination, available data sets from countries with more than 0.5 million inhabitantswere analyzed (in total 39 countries). To accurately estimate the influence of IVR onCOVID-19 deaths and mitigate effects of confounding variables, a sophisticatedranking of the importance of different variables was performed, including aspredictor variables IVR and some potentially important geographical andsocioeconomic variables as well as variables related to non-pharmaceuticalintervention. The associations were measured by non-parametric Spearman rankcorrelation coefficients and random forest functions.

Results: The results showed a positive association between COVID-19 deaths andIVR of people≥65 years-old. There is a significant increase in COVID-19 deathsfrom eastern to western regions in the world. Further exploration is needed to explainthesefindings, and additional work on this line of research may lead to prevention ofdeaths associated with COVID-19.SubjectsEpidemiology, Global Health, Immunology, Infectious Diseases, Public HealthKeywordsSARS-CoV-2, Global health crisis, Risk factors, Virus interference,Geographical longitude, Lockdown, Face mask useINTRODUCTIONThe coronavirus disease 2019 (COV