"The rules have changed. We have a different epidemic now that we did in May." Adding more insight into the CDC’s updated mask guidance, newly published details of the Provincetown outbreak raise ...

SAN FRANCISCO -- Earlier in the pandemic, experts had hoped if we can get 75% of Americans vaccinated, we can contain the coronavirus. Thursday, we're at just over 50% vaccinated. But 75% is no longer ...

Estimates show the variant accounts for over 51% of all new cases nationwide. A highly contagious variant of the novel coronavirus that was initially identified in India is now the dominant strain in ...

Moderna on Tuesday released preliminary data indicating its vaccine is likely to hold up against several variants of concern, including the Delta variant, which is predicted to become the dominant ...

SAN FRANCISCO (KGO) -- The Centers for Disease Control and Prevention (CDC) released new data Friday indicating the Delta variant is twice as infectious as previously thought, and a recent analysis ...

Since SARS-CoV-2 first emerged in late 2019 the virus has spawned dozens of lineages, a handful of global "variants of concern" that changed the course of the pandemic.