Can the Common Cold Prime Our Immune System to Fight COVID?

During 2020, much of the world didn’t experience normal cold or flu seasons. Although COVID ran rampant, other common viruses were notably absent, including respiratory syncytial virus (RSV), a highly contagious virus that normally circulates in the winter and can be particularly dangerous for children.

When RSV made a surprising, out-of-season return in the summer of 2021, it caused dramatic spikes in child infections and hospitalizations around the world. Experts blamed the surge on “immunity debt” — the failure to build up immunity against common viruses, in this case due to widespread mitigation measures for COVID.

How does the immune system usually stay up to date and out of debt? Through exposure.

Whether from vaccination or infection, the immune system learns how to combat pathogens through practice. (Vaccines act more like a friendly ­tutor to the immune system; infections provoke a real-time battle.)

Like a muscle, the immune system needs exercise to stay in shape. “White blood cells multiply in response to challenge: Each exposure to a germ gives you more immune cells to respond faster and more aggressively the next time that germ tries to attack.”

Like a muscle, the immune system needs exercise to stay in shape. “White blood cells multiply in response to challenge: Each exposure to a germ gives you more immune cells to respond faster and more aggressively the next time that germ tries to attack,” explains immunology expert Mary Ruebush, PhD, author of Why Dirt Is Good: 5 Ways to Make Germs Your Friends.

B and T cells are two critical components of the adaptive immune system. They recognize specific attackers, produce antibodies to destroy them, and regulate the action of other immune cells. These cells can have long lifespans, providing protection against pathogens they’ve met before, sometimes for decades.

“But if we don’t keep them on their toes by showing them they’re doing a great job guarding the environment, they can become quiescent and die,” notes Ruebush. “Then you need to start from scratch, with immune cells learning by bumping into pathogens, which happens slowly.”

Keeping these cells busy helps them stay in fighting shape. “In normal circumstances, if you’re less than perfect about personal hygiene, relaxed about your environment, and hugging people at church, that gives those cells more of a kick in the butt to keep them interested in what’s going on around them,” she says.

There’s even evidence that battling a cold recently may provide some immune protection against the virus that causes COVID.

There’s even evidence that battling a cold recently may provide some immune protection against the virus that causes COVID. In a study pub­lished in Science in 2020, researchers found that T cells trained to respond to common-cold-causing coronaviruses will cross-react to the virus’s spike protein.

Multiple studies have also found that a recent cold correlates to less severe symptoms in those who later contract COVID.

While vaccination remains the best tool to prevent severe outcomes from COVID, this research suggests that keeping your immune system primed by engaging with the world may be a worthwhile addition to your immunological toolkit.

“What keeps our immune response strong is being experienced in dealing with things in the environment and managing them,” says Ruebush. “That makes us stronger and causes us to react more normally to the things around us.”

This was excerpted from “Making Peace with Microbes” which was published in the April 2022 issue of Experience Life magazine.