Differing strains of the coronavirus continue to appear around the world and a new COVID-19 variant, the so-called "Delta" variant, has health experts concerned. The variant, otherwise known as B.1617 ...

"As these viruses continue to evolve, public health officials watch carefully to see whether new strains will be more easily spread or cause more severe disease, and they are continuously testing to ...

With the Delta variant in play, federal health officials are analyzing the latest numbers to look at the frequency and seriousness of COVID-19 breakthrough infections. Will we need booster shots? And ...

LOS ANGELES (KABC) -- While overall COVID-19 rates remain relatively low in Southern California amid continuing vaccination efforts, officials are increasingly worried about a growing threat from the ...

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 ...

Vaccine effectiveness against COVID-19 infection dropped from 91% to 66% once the delta variant accounted for the majority of circulating virus, according to a study published Tuesday by the U.S.

More than half of the U.S. population has received at least one dose of the coronavirus vaccine. But based on a new scenario model by Johns Hopkins the next three months are crucial if we want to ...

The proportion was estimated at approximately 3% in late May. A highly contagious variant of the novel coronavirus that was initially identified in India now accounts for about 58% of all COVID-19 ...

Part of the problem is low vaccination rates, experts said. The Centers for Disease Control and Prevention assigned two federal "surge team" members to Missouri this week to help fight the state's ...