Ewen Callaway in Nature:
Here we go again. Nearly six months after researchers in South Africa identified the Omicron coronavirus variant, two offshoots of the game-changing lineage are once again driving a surge in COVID-19 cases there.
Several studies released in the past week show that the variants — known as BA.4 and BA.5 — are slightly more transmissible than earlier forms of Omicron1, and can dodge some of the immune protection conferred by previous infection and vaccination2,3.
“We’re definitely entering a resurgence in South Africa, and it seems to be driven entirely by BA.4 and BA.5,” says Penny Moore, a virologist at the University of the Witwatersrand in Johannesburg, South Africa, whose team is studying the variants. “We’re seeing crazy numbers of infections. Just within my lab, I have six people off sick.”
However, scientists say it is not yet clear whether BA.4 and BA.5 will cause much of a spike in hospitalizations in South Africa or elsewhere.