When will the omicron wave peak in the U.S.?

In Florida, as the incredibly contagious omicron variant spreads, the number of reported COVID cases jumped up 948% between December 20 and January 2. In New York, cases nearly tripled. In D.C., cases were up 485%. The seven-day average of new cases in the U.S is now higher than it’s been at any other time during the pandemic. The real number is surely even higher than that since the holidays have delayed reporting, many people taking tests at home aren’t sharing their data, and others aren’t getting tested at all.

But in South Africa, where the omicron variant was first detected in late November and then surged, cases quickly peaked: By the week of Christmas, the number of new cases was 30% lower than it had been the week before. In the U.S., scientists say the current wave of cases is likely to also peak quickly.

Some states are likely to see new infections start to drop by the middle of January, says Christopher Murray, director of the Institute for Health Metrics and Evaluation at the University of Washington, which forecasts the growth in infections globally. In December, the group projected that the peak might happen in the U.S. by the end of January. Now it believes it will happen even faster. “It will depend on the state,” Murray says. “Some states haven’t started—Montana is yet to start its omicron wave. But we would expect peaks sometime from the middle of January into the middle of February.”

The projection takes into account factors including how many people are vaccinated and boosted, how many are wearing masks, and how many people have already been infected with a previous COVID variant. (In South Africa, though a lower percentage of people are vaccinated than in the U.S., many more had already had COVID before omicron emerged). If behavior changes, so would the number of cases—if 80% of people wore masks, for example, the number of cases at the peak might be cut in half.

Another projection, from Columbia University researchers, has a similar timeline, suggesting that cases in the U.S. could peak sometime the week of January 9. In hard-hit New York City, cases might begin to drop this week. Despite the wave, there is some relatively good news: So far, omicron cases are sending fewer people to hospitals and causing fewer deaths than earlier COVID cases. The peak number of infections may be around five times higher than the worst peak last winter, but the number that become hospitalized may be similar to last winter, says Murray. But a smaller percentage of a very large number still will mean a lot of people in the hospital, which could overwhelm them, especially as healthcare workers continue to get sick themselves. “Massively more infections certainly can lead to a lot of stress on hospital systems in some places,” he says.