The common cold can make you miserable, but it might also help protect you against COVID-19, a new study suggests.
The researchers added that people who've had COVID-19 may be immune to it for a long time, possibly even the rest of their lives.
The research focused on memory B cells, long-lasting immune cells that detect pathogens, produce antibodies to destroy them, and remember them for the future.
The study authors compared blood samples from 26 people who were recovering from mild to moderate COVID-19 and 21 healthy people whose samples were collected six to 10 years ago, long before they could have been exposed to COVID-19.
They found that B cells that attacked previous cold-causing coronaviruses appeared to also recognize the coronavirus (SARS-CoV-2) that causes COVID-19.
This could mean that anyone who's ever been infected by a common cold coronavirus -- nearly everyone -- may have some amount of immunity to COVID-19, according to infectious disease experts at the University of Rochester Medical Center in Rochester, N.Y.
The researchers also found that SARS-CoV-2 triggers memory B cells, which means those immune cells are ready to fight the coronavirus the next time it shows up in the body.
"When we looked at blood samples from people who were recovering from COVID-19, it looked like many of them had a preexisting pool of memory B cells that could recognize SARS-CoV-2 and rapidly produce antibodies that could attack it," study author Mark Sangster said in a university news release. He's a research professor of microbiology and immunology.
Because memory B cells can survive for decades, they could protect COVID-19 survivors from subsequent infections for a long time, but further research is needed to confirm that, according to the authors.
"Now we need to see if having this pool of preexisting memory B cells correlates with milder symptoms and shorter disease course -- or if it helps boost the effectiveness of COVID-19 vaccines," study co-author David Topham, professor of microbiology and immunology, said in the release.
The study was published in the September/October issue of the journal mBio.
The U.S. Centers for Disease Control and Prevention has more on COVID-19.