Two of the vaccines we have for COVID-19 have the distinction of being the first mRNA vaccines to see widespread use in ...

Some viruses mutate more rapidly than others. Learn more about why that is and what that means for your health.

A real-world test of Pfizer’s COVID-19 vaccine in more than half a million people confirms that it’s very effective at preventing serious illness or death, even after one dose. Wednesday’s published ...

Johnson & Johnson said Thursday that new data shows that its single-shot COVID-19 vaccine provides protection against the virus for at least eight months and effectively prevents infection from ...

On December 18, a San Diego emergency room nurse was given a shot of the COVID-19 vaccine. A week later, he tested positive for the virus, CNN affiliate KGTV reported. Stories like this will become ...

Younger Americans are more likely than older people to say these changes have influenced their decision. Among adults under 30 who are familiar with the CDC’s changes, about half say these changes ...

On May 20, U.S. Food and Drug Administration (FDA) officials announced that Covid-19 vaccines will no longer be available to everyone. Instead, annual boosters will be limited to people ages 65 and ...

WASHINGTON -- The top U.S. infectious disease expert said AstraZeneca's suspension of final testing of its COVID-19 vaccine candidate shows "one of the safety valves" built into the studies to spot ...