Can a flu shot help stop a cold virus?

Some vaccines made with weakened viruses don’t just protect against the specific disease—they might also give your whole immune system a boost that could help protect your brain from damage, unlike other vaccines that only target one part of the virus.

Giving mice a special flu vaccine a few days before exposing them to RSV (a virus that causes colds) stopped the RSV from multiplying in their lungs—even though the flu vaccine wasn’t designed to fight RSV at all.

When mice were given a special vaccine called X-31ca, their bodies quickly made protective signals and sent in immune soldiers to their lungs, and when they later got a common lung virus (RSV), their lungs stayed calmer and less inflamed than usual.

When scientists gave mice a special flu-like vaccine called X-31ca, it helped them fight off a common cold virus — but only if their immune system had two specific sensors (TLR3 and TLR7). When those sensors were turned off, the vaccine stopped working, meaning those sensors are essential for the quick, general protection it provides.

A flu-like vaccine called X-31ca helps mice fight off a common cold virus called RSV, but only for a few days—after about two weeks, it doesn’t work at all.