How dangerous is BA.2, the new COVID-19 variant?

As COVID-19 case numbers climb in East Asia and now Europe — a surge largely attributed to the BA.2 subvariant of omicron — it makes sense that concern would rise in the U.S. It’s happened before during the course of the now two-year-old pandemic: a surge on another continent is followed by a surge in North America. But Shangxin Yang, a professor of pathology and laboratory medicine at the David Geffen School of Medicine at UCLA, advises against an overreaction. “This is normal and we shouldn’t be too concerned about it,” Yang said. “For those who are not yet boosted, go get boosted. For those who are not vaccinated, go get vaccinated. If we have a very general practice of behavior, we can do just fine.” Viruses mutate to survive. To date, the two biggest variants of SARS-CoV2, the virus responsible for COVID-19, have been the delta and omicron variants. They had very different...