U.S health officials are urging Americans to get their flu shots this year in the hopes of thwarting a winter “twindemic”—a situation in which both influenza and COVID-19 spread and sicken the public. But a new study suggests that there could be another key reason to get a flu jab this year: it might reduce your risk of COVID-19. The research, released as a preprint that has not yet been peer-reviewed, indicates that a flu vaccine against the influenza virus may also trigger the body to produce broad infection-fighting molecules that combat the pandemic-causing coronavirus.
The paper is in line with some other recent studies published in peer-reviewed journals that point to similar effects. But researchers caution the research is preliminary and needs to be bolstered by more rigorous experiments.
In the new study, Mihai Netea, an infectious disease immunologist at Radboud University Medical Center in the Netherlands, and his colleagues combed through their hospital’s databases to see if employees who got a flu shot during the 2019–2020 season were more or less likely to get infected by SARS-CoV-2, the virus behind COVID-19. Workers who received a flu vaccine, the researchers found, were 39 percent less likely to test positive for the coronavirus as of June 1, 2020. While 2.23 percent of nonvaccinated employees tested positive, only 1.33 percent of vaccinated ones did. Netea and his team posted their findings on the preprint server MedRxiv on October 16.