National numbers, April 9

In the past week (March 30 through April 5), the U.S. officially reported about 120,000 new COVID-19 cases, according to the CDC. This amounts to:

• An average of 17,000 new cases each day
• 37 total new cases for every 100,000 Americans
• 12% fewer new cases than last week (March 23-29)

In the past week, the U.S. also reported about 15,000 new COVID-19 patients admitted to hospitals. This amounts to:

• An average of 2,100 new admissions each day
• 4.5 total admissions for every 100,000 Americans
• 12% fewer new admissions than last week

Additionally, the U.S. reported:

• 1,800 new COVID-19 deaths (250 per day)
• 88% of new cases are caused by Omicron XBB.1.5; 5% by XBB.1.9.1; 2% by XBB.1.5.1; 0.4% by CH.1.1 (as of April 8)
• An average of 40,000 vaccinations per day

COVID-19 spread in the U.S. remains at a high plateau, according to reported cases, hospitalizations, and wastewater surveillance. Experts are watching new variants that mutated from XBB as potential drivers of more transmission this spring.

While the case numbers may seem low, remember that cases are now severely undercounted—potentially by up to 20 times. So, when the CDC reported about 37 new cases per 100,000 people last week, the true number could be closer to 700 new cases per 100,000. It’s becoming harder and harder to get a PCR test, as sites shut down and the federal health emergency’s end approaches, which will further drive undercounting.

Wastewater data, on the other hand, continue to show that coronavirus levels in the U.S. are significantly higher than they were at this time in 2022 and 2021. Last week, I wrote that Biobot’s dashboard showed a slight increase in COVID-19 spread across the country; after this week’s data updates, that appears to have been a blip, with the company’s national surveillance again showing a plateau.

Biobot’s regional data also indicates that COVID-19 spread has remained relatively consistent in the last few weeks. The Northeast and Midwest have slightly higher coronavirus levels than the South and West, but there aren’t significant differences between these regions.

As I wrote last week, new subvariant XBB.1.9.1 remains more prevalent in the Midwest, particularly the region including Iowa, Kansas, Missouri, and Nebraska (where it caused about 18% of new cases in the last week, per CDC estimates). Some wastewater testing sites in these states have reported increases recently, but there isn’t a consistent increase across the board.

Nationally, the CDC estimates that XBB.1.9.1 caused about 5% of new cases nationwide in the week ending April 8, compared to 88% caused by XBB.1.5. XBB.1.9.1 has been growing relatively slowly, so it may be a few more weeks before we see it either outcompete XBB.1.5 or die out at low levels. Experts are also watching XBB.1.16, which drove a surge in India recently but has not shown up in large numbers in the U.S. yet.

Will the U.S. see a new surge this spring? It seems possible, thanks to Omicron’s continued evolution and our lack of collective safety measures. But continued declines in data reporting will make it harder to see this surge than it’s ever been.

In this environment, wastewater surveillance is growing more and more valuable. It’s also probably a good idea to keep taking some basic precautions (like masking in public indoor spaces, or regularly testing) no matter how low the reported cases get in your community.