Add Yahoo as a preferred source to see more of our stories on Google. The Omicron booster will protect against BA.5 and BA.4 as well as the original coronavirus strain. (Getty Images) (Getty Images) ...

The World Health Organization said Wednesday that 23 countries across the world have reported cases of the highly mutated omicron Covid-19 variant. "At least 23 countries from five of six WHO regions ...

Omicron subvariants BA.4 and BA.5 are circulating at low levels in several countries within Southern Africa and Europe, according to the World Health Organization. The two subvariants of the highly ...

Why has the World Health Organization (WHO) designated the new, heavily-mutated coronavirus variant Omicron a “variant of concern?” How is it that the next-in-line letters of the Greek alphabet, Nu ...