first detected in India.It’s a version of the coronavirus that has been found in more than 80 countries. In the U.S., it makes up at least 20% of reported COVID-19 cases and is expected to become the dominant strain in the country, according to health officials.The delta variant got its name from the World Health Organization, which names notable variants after letters of the Greek alphabet.Viruses constantly mutate, and most changes aren't concerning.
But there is a worry that some variants might evolve enough to be more contagious, cause more severe illness or evade the protection that vaccines provide.Here’s what is currently known about the delta variant:The U.S.