With a caseload nearly twice that of the worst single days of last winter, the United States shattered its record for new daily coronavirus cases, a milestone that may still fall short of describing the true toll of the Delta and Omicron variants because testing has slowed over the holidays.
As a second year of living with the pandemic was drawing to a close, the new daily case total topped 488,000 on Wednesday, according to a New York Times database. (The total was higher on Monday, but that number should not be considered a record because it included data from the long holiday weekend.)
Wednesday’s seven-day average of new daily cases, 301,000, was also a record, compared with 267,000 the day before, according to the database. In the past week, more than two million cases have been reported nationally, and 15 states and territories reported more cases than in any other seven-day period.
The rise has been driven by the highly contagious Omicron variant, which became dominant in the United States last week. So far, however, the increase has not resulted in more severe disease, as hospitalizations have increased only 11 percent and deaths have decreased slightly in the past two weeks.
Still, Wednesday’s numbers may not fully illustrate the havoc caused by the two variants, as infections sideline huge numbers of workers, worsening a labor shortage that is upending the hospitality, medical and travel industries, among others.
Demand for tests has outstripped supply, particularly in the last month as the Omicron variant has spread with astonishing speed. And the holiday season offers its own disruptions to the U.S. case curve, with many testing sites offering limited hours and labs and government offices not open to report test results.
Last year, the national case curve showed pronounced declines after Thanksgiving and Christmas that did not reflect real decreases in new infections. The impact of holidays may be even more noticeable this time around, as illustrated by the Labor Day holiday in September, because states are reporting data less consistently than they did a year ago.
Before Tuesday, the seven-day U.S. average had peaked on Jan. 11 at 251,232. That was during a catastrophic winter when vaccinations were still relatively new. Today, more than 62 percent of Americans are fully vaccinated.
No matter what the true caseload is now, the United States has confronted a new set of challenges as the Delta and Omicron variants have converged. The variants have disrupted holiday travel and gatherings, depleted hospital staffs and plunged the United States into another long winter.
Record caseloads are being reported in a long list of U.S. cities where vaccination rates are relatively high, including New York, Washington, Seattle, San Francisco, Boston, Atlanta and Detroit.
Experts say there are two reasons for the high numbers in urban areas: population density and more testing.
Cities are tightly packed hubs for travel and socializing, which leaves people more susceptible to the highly contagious Omicron variant, said Dr. Kirsten Bibbins-Domingo, a physician and epidemiologist at the University of California, San Francisco. And testing is more common in major urban centers “precisely because we’re worried about big surges overwhelming hospitals,” she added.
In fact, she said, city caseloads may be higher than reported because of the rise in at-home tests whose results often don’t get reported to the authorities, so they aren’t reflected in official totals.
