Less corona in hospital staff after flu shot

Hospital staff who received a flu shot in the 2019-2020 season were less likely to be infected with the coronavirus during the first wave. Whether the vaccine actually offers protection against the corona virus remains to be investigated. Scientists from Radboudumc published these results in a preprint which appeared on server medRxiv. The results have yet to appear in a scientific journal.

Flu viruses require 290,000 to 650,000 annually kill worldwide, including a few thousand Dutch people. Around 6 million people over 60 and people with, for example, a heart or lung disease in the Netherlands receive an invitation every year to get the flu shot. Healthcare providers are also asked to get a shot because they could transmit the virus to patients.

Tuberculosevaccin

Some researchers suspect that vaccines that do not target the coronavirus may still contribute to protection against the virus by boosting the immune system. Scientists have previously shown this for the tuberculosis vaccine. The idea is as follows. Normally, a vaccine, for example for TB, produces specialized immune cells that attack the tuberculosis bacteria in the event of a subsequent infection because they have a memory to do so. That regulates the acquired immune system. But the vaccine can also boost the innate immune system. By stimulating this system with a vaccine, the body continues to produce more defense proteins that lead immune cells to the infection long afterwards.

Researchers at Radboud university medical center added last season’s flu shot to blood cells of healthy people. Then they added inactivated coronavirus (working with live virus requires extra security measures). In the cells that had previously been exposed to the flu vaccine, the researchers observed a higher production of various immune proteins than in cells that had not been exposed to them.

Cautious people

The scientists also looked at the number of corona infections among Radboudumc personnel who received the flu shot last year and compared this with the number of infections among unvaccinated personnel. An infection was found in 184 people. 2.23 percent of the non-vaccinated became infected. This was 1.33 percent among the vaccinated.

Professor of Vaccinology Anke Huckriede of the UMC Groningen, who was not involved in the study, is not yet convinced: “The tricky part is that the researchers could not take into account factors that could influence the result. For example, people who get vaccinated may be more careful and do everything they can to prevent a corona infection. ”

According to her, earlier studies do not yet provide a definitive answer about the effect of the flu shot. “There is a lot of disagreement whether the flu shot has a positive or negative effect on death from Covid-19. A large, well-executed study is needed. ”

–