Pfizer and BioNTech report that their updated mRNA COVID-19 vaccine for the 2025–2026 season produced strong immune responses ...

For at least 10 months after a COVID-19 infection, your immune system can provide good protection against symptomatic illness the next time around, a new study found, and the risk of severe illness is ...

Pfizer and partner BioNTech said on Monday their updated COVID-19 vaccine showed an increased immune response in adults aged ...

It could impact whether a person gets sick. The good news is most people have some COVID-19 immunity, according to CDC researchers. But that still doesn’t mean a person can’t get sick.

Covid-19 was never just another cold. We knew it was going to stick around and keep changing to try to get the upper hand on our immune systems. But we've changed, too. Our B cells and T cells, ...

Experts say it’s less risky to catch Covid-19 than it used to be, but there are still good reasons not to treat it casually.

The XFG COVID-19 variant, aka "Stratus," is spreading rapidly in the U.S. as cases climb. Here's what to know about symptoms ...

Good Covid-19 data is hard to come by and harder to interpret. So if people are less likely to be hospitalized or die from a Covid-19 infection now, has the danger passed?