Experts say there’s another good reason to get your flu vaccine this year.

Top virologist Dr. Robert Gallo says that if the vaccine contains a live virus, there is a chance it may offer some protection against COVID-19. Gallo, who is chairman of the Global Virus Network, says that live, attenuated vaccines, which means the actual pathogen is still living but considerably weakened, appear to offer protection against other illnesses.

According to NPR, an example is the tuberculosis vaccine called bacilli Calmette-Guerin, or BCG, that contains a weakened  strain of TB from bovines. Scientists found that it not only protected children against the disease, but appeared to reduce all over mortality rate by boosting the immune system. A similar pattern was observed in the measles and oral polio vaccines.

Recent research reveals that people who have received vaccinations for other diseases seem to be less affected by the virus. Even if they catch the virus, their symptoms appear to be milder.

According to CNN, these factors may account for the reasons some individuals get sicker than others. Dr. Andrew Badley, a professor of infectious disease at the Mayo Clinic and leader of its COVID-19 research task force, said that people who had a variety of vaccines such as influenza, pneumococcus, and others, appear to have a lower risk of getting COVID-19.

It is called immune training, he said:

“A good analogy is to think of your immune system as a muscle. The more you exercise the muscle, the stronger it will become if you need it.”

Currently scientists from around the world are testing whether the BCG or live polio vaccine can offer some protection against SARS-CoV-2, the virus that causes COVID-19.

Gallo, who was one of the scientists who discovered HIV, says there is no time like the present to get vaccinated against the flu. The nasal spray called FluMist is the vaccine that contains live, attenuated flu viruses, according to CNN. The second form of vaccine, the flu shot, contains an inactivated form of the virus.

“You watch,” Gallo says. “People who get the live flu vaccine will also be protected against the COVID-19. That’s the hypothesis.”