Several COVID-19 variants are acting uniquely enough to qualify as a distinct strain. And you might have heard about one on ...

The delta variant is fueling the COVID-19 surge in the United States, but experts warn that a more dangerous variant could emerge if more Americans don't get vaccinated. Delta is the most recent of ...

The delta coronavirus variant surging across the United States appears to cause more severe illness and spread as easily as chickenpox, according to an internal document from the US Centers for ...

WASHINGTON - In a press briefing Friday, the head of the WHO said the delta variant is "quickly becoming the dominant strain in many countries," and thus, the world is in a "very dangerous period" of ...

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 ...

SAN FRANCISCO (KGO) -- Bay Area doctors and health officials are concerned about the rapid spread of the COVID-19 Delta variant, warning significant outbreaks could trigger a setback for the state.

NEW YORK, N.Y. — Pfizer announced Wednesday that data shows a third dose of its COVID-19 vaccine can “strongly” boost protection against the highly transmissible delta variant. The pharmaceutical and ...

ATLANTA, Ga. — The delta variant that’s now the dominant strain of coronavirus in the U.S. appears to be as transmissible as chickenpox, according to an internal document from the Centers for Disease ...

UNITED STATES — The delta variant of COVID-19 is becoming even more dominant throughout the country. As numbers are rising, so is the amount of mixed messaging. Health professionals say getting the ...

The more contagious Delta variant of Covid-19 now makes up 83% of sequenced samples in the United States, US Centers for Disease Control and Prevention Director Dr. Rochelle Walensky said Tuesday.