A New Wave of Covid-19 Is Coming.

The next wave of Covid-19 is coming, and in some parts of the United States, it’s already here. Are you ready?

The culprit this time is BA.2, a subvariant of the highly infectious Omicron variant. Nobody knows for sure how much havoc it will cause, but BA.2 has already led to a surge of cases in Europe and is now the dominant version of the coronavirus in the United States and around the world.

What Are the Symptoms of Omicron?

Researchers are tracking an uptick in cases in the United States, and they’ve detected a rise in the viral particles recovered from nearly 150 wastewater-surveillance sites. Because people can shed the coronavirus even if they never develop symptoms, pieces of the virus collected in wastewater can serve as advance warning several days before official case counts rise, said Bronwyn MacInnis, who directs pathogen genomic surveillance at the Broad Institute in Cambridge, Mass. Over the past two weeks, Dr. MacInnis’s group has seen a rapid increase in levels of the BA.2 subvariant in the Northeast.