BA.2 becomes dominant COVID-19 strain

The Centers for Disease Control and Prevention said Tuesday that omicron subvariant BA.2 currently accounts for about 54.9 percent of coronavirus cases in the United States. The World Health Organization said on Mar. 22 it also accounts for 86 percent of cases worldwide, but overall infections have been declining. BA.2 seems to be more infectious than BA.1, another omicron subvariant, but international studies show it does not cause serious disease. It’s been dubbed the “stealth variant” because a PCR test can’t distinguish it from other variants.

Will there be another COVID-19 spike? The WHO said preliminary data suggests infection with BA.1 protects from BA.2 for a while. Last week, the seven-day average of daily new cases in the U.S. decreased 5.4 percent compared to the previous week. The Food and Drug Administration (FDA) and the CDC approved a second Moderna or Pfizer COVID-19 booster shot for people age 50 and older on Tuesday. The FDA made the decision without input from its independent panel of experts, which has debated how much data to require. Companies are working on omicron-specific vaccines, but the National Institutes of Health recently found “no significant advantage” in its test monkeys to using such targeted boosters.

Dig deeper: Read Liz Lykins’ report in Beginnings on the spread of BA.2 across the U.S.