Mutations

The dangerous Delta variant of the coronavirus is spreading so quickly in the United States that it's likely the mutant strain will become predominant in the U.S. within weeks, according to a new analysis.

The variant, first identified in India, is the most contagious yet and, among those not yet vaccinated, may trigger serious illness in more people than other variants do, say scientists tracking the spread of infection.

The Delta variant apparently already accounts for at least 14% of all new infections, according to the research analysis posted online Monday of more than 242,000 infections nationwide over the last six months.