There are several interesting and unthought-of findings during the COVID-19 pandemic and a report showing the reduction in COVID-19 risk following flu vaccination is one of such mystifying findings.
A study from Qatar published in medRxiv preprint reported that the health-care workers who got the influenza vaccine were also protected from COVID-19.
Researchers studied more than 30,000 health care workers in Qatar who got flu vaccines prior to the release of COVID-19 vaccines. After 90 days of receiving the flu shots, participants were tested for the coronavirus with a PCR test.
Overall, the flu shots appeared to reduce the risk of COVID-19 infection by nearly 30% in two weeks following vaccination.
Furthermore, the flu shot reduced the risk of severe or fatal COVID-19 by almost 90%. Although the study only included a small number of severe COVID-19 cases, the observation that flu shots are tied to a reduction in both COVID-19 infections and disease severity strongly suggests that the protection is legitimate. While not yet clear why flu vaccines, which are composed of killed influenza viruses, would also protect against COVID-19 or how long this protection lasts, this is another reason to complete the recommended vaccine regimens including the yearly flu shots.