California healthcare workers didn't know they were fighting a new variant this winter. Their trauma should be a warning.

California healthcare workers didn't know they were fighting a new variant this winter. Their trauma should be a warning.: The CAL.20C variant was first identified in Los Angeles in July, then disappeared from the record until October. But by January, it accounted for 44% of Southern California coronavirus samples in one study, and more than half of California samples in another. Several other factors contributed to Southern California's winter surge - holiday travel, crowded housing, pandemic fatigue - but many researchers think the variant played a role.