"As these viruses continue to evolve, public health officials watch carefully to see whether new strains will be more easily ...

COVID-19 variant XFG accounted for 0% of U.S. cases in May. By late-June, it became the third-most common strain.

Add Yahoo as a preferred source to see more of our stories on Google. Getty Images An alleged warning has spread online for years about a supposed "new COVID-Omicron XBB variant" — a new strain of the ...

A variant strain of the coronavirus, one that was first discovered in the United Kingdom, is now the dominant strain of the virus circulating throughout the United States, CDC Director Rochelle ...

As the respiratory illness season begins, COVID cases have remained relatively under control in the United States into the beginning of fall. While the United States by and large is experiencing ...

The fast-spreading delta variant of the coronavirus has been gaining traction worldwide since it was first detected in India. It’s a version of the coronavirus that has been found in more than 80 ...

Flu season isn't in full swing yet in the United States, but a mutated strain of the virus that has caused severe outbreaks abroad is sparking concern about the winter ahead. A new version of ...