Another COVID wave is looming

Oddly enough, America’s recent laissez-faire approach to the pandemic has made case rates easier to predict here. Throughout the pandemic, the most difficult part of modelers’ jobs has been accounting for how policy and Americans’ behavior would change, says Lauren Ancel Meyers, who directs the COVID-19 Modeling Consortium at the University of Texas at Austin. But during the winter, schools largely stayed open and Americans largely went about their lives. Suddenly, the projections Meyers and her team made were spot-on. “We’re not used to being that accurate,” she told me.

But that doesn’t mean modelers are ready to say exactly what’s next for America. “What we found in the past two years is that the models have struggled at these critical change points,” Truelove told me. We’ll know if we’ve entered a trough, he said, only after it’s over and case rates climb up again. Meyers said she expects to have better predictions in a week or so. She wants more time to see whether cases start to plateau or increase in parts of the U.S. and to get more information about how long people are protected from infection or disease after a bout with Omicron. She also wants to know more about how easily BA.2 can infect people who have survived either of the two subvariants, BA.1 and BA.1.1, that have been responsible for the bulk of American cases since December.

BA.2 is thought to be slightly more transmissible than BA.1, and it’s already in the U.S. That might sound ominous, considering what’s happening in Europe, and it might also suggest that a U.S. wave is coming soon, according to the pattern set by Delta and Omicron. Hanage assured me that BA.2 will almost certainly beat out other variants here, too, but that doesn’t mean that the U.S. is doomed to suffer an identical surge. When BA.2 entered Europe, it took off almost immediately. In the U.S., Hanage said, its rise has been much slower, possibly because it’s competing with both BA.1 and BA.1.1. Even if BA.2 were to start taking over in earnest tomorrow, it would be doing so during a much lower trough, and probably less virus-friendly weather conditions, than it encountered when it made its bid for dominance in the U.K.