According to a new study, a flu shot could reduce the number of SARS-CoV-2 infections. Based on an analysis of the medical records of more than 27,000 patients in Michigan, USA who were tested for Covid-19 in July, it found that anyone who had been vaccinated against influenza the previous year was less likely to have had a positive test. The disease caused by the SARS-CoV-2 coronavirus.
Of the 27,201 patients who were tested with Covid-19, 1218 had a positive result – that is, 4.5% of the total. Therefore, the lead author of the study, Marion Hofmann Bowman, recommends continuing to take the flu vaccine.
Looking at the data with variables (such as race, gender, age, and other health-related factors) in mind, it turns out that of those who took the flu vaccine, only 4% got Covid-19. Among those who had not received the flu vaccine, the percentage of tests positive for Covid-19 rose to 4.9%.
Although there seemed to be a small difference, the scientists concluded that the likelihood of a positive Covid-19 test in patients vaccinated against Covid-19 was reduced by 24%.
It’s not yet clear why it is happening: it may be related to the cautious behavior of people who get vaccinated against the flu. Or it can be due to “trained immunity”, through which exposure to a disease can help the immune system respond to other threats.
“It is possible that patients receiving the flu vaccine may also be more socially aloof and follow recommended guidelines. However, it is also plausible that the flu vaccine has a direct biological effect on the relevant immune system in order to fight the SARS-CoV-2 virus, ”says Marion Hofmann Bowman, professor of internal medicine and cardiologist at the Frankel Center. of Cardiovascular Medicine at the University of Michigan.
In this study, patients who received the flu vaccine were also less likely to require hospitalizations and ventilators.
There are other studies examining the effects of the flu vaccine on respiratory disease, including the Household Influenza Vaccine Evaluation (HIVE) study from the University of Michigan’s School of Public Health. “It is important to provide specialists with other tools to encourage patients to use vaccines that are already available, effective and safe,” said study co-author Carmel Ashur, assistant professor of internal medicine, also at the Frankel Center for Cardiovascular Medicine.