Newer, fitter descendants of Omicron variant begin to drive their own coronavirus waves

Average daily hospitalizations are up about 10% since last week, according to data collected by the US Department of Health and Human Services. The culprit this time appears to be a spinoff of Omicron's BA.2 subvariant called BA.2.12.1, which was first flagged by New York state health officials in April. BA.2.12.1, which is growing about 25% faster than its parent virus, BA.2, accounts for nearly 37% all Covid-19 cases across the US, according to new estimates from the CDC. BA.2 caused an estimated 62% of all Covid-19 cases last week, down from 70% the week before.