Data from the European Union show a correlation between flu vaccine coverage and COVID-19 mortality.
The data show a stark difference between low-coverage countries and high-coverage countries:
A report on Gateway Pundit adds: Among countries omitted in the EU data was Belgium, which has the highest Covid-19 mortality rate in the world, at 763 per million. While specific data for older people were not available on the official Belgian statistics website, flu vaccination coverage of the overall population is relatively high.
This correlation is bolstered by the connection found in a 2019 study:
Receiving influenza vaccination may increase the risk of other respiratory viruses, a phenomenon known as virus interference. Test-negative study designs are often utilized to calculate influenza vaccine effectiveness. The virus interference phenomenon goes against the basic assumption of the test-negative vaccine effectiveness study that vaccination does not change the risk of infection with other respiratory illness, thus potentially biasing vaccine effectiveness results in the positive direction.
They specifically tested against coronavirus:
Vaccine derived virus interference was significantly associated with coronavirus and human metapneumovirus; however, significant protection with vaccination was associated not only with most influenza viruses, but also parainfluenza, RSV, and non-influenza virus coinfections.
The outliers like Finland and Malta could be explained by the population’s high levels of vitamin D, which appears to be protective against COVID-19. A recent study in the Irish Medical Journal states:
The circumstantial and experimental evidence suggests that vitamin D may have an important supportive role for the immune system, particularly in regulating cytokine response to pathogens. Vitamin D levels are low in countries in Europe which have high infection and mortality rates. There is strong plausible biological hypothesis and evolving epidemiological data supporting a role for vitamin D in Covid-19.
UPDATE: A new study shows that vitamin D deficiencies heavily correlate to the death rate in COVID-19 patients: