The Food and Drug Administration authorized an updated formula for mRNA COVID-19 vaccines to adjust for the XBB1.5 variant this fall amid a surge in cases right after summer. With a long schedule of ...

Antibodies to SARS-CoV-2, the virus that causes Covid-19, were present in the blood of 96.4 percent of Americans over the age of 16 by September 2022. That’s according to a serosurvey — an analysis ...