US COVID hospitalizations rise for second week in a row. Is it a summer increase?

Weekly COVID-19 hospitalizations are up more than 12% across the country, according to new data released by the Centers for Disease Control and Prevention, marking a second straight week of this key indicator of the virus’s climb.

At least 8,035 hospitalizations of patients diagnosed with COVID-19 was reported for the week of July 22 nationwide, the CDC said late Monday, up from 7,165 during the previous week.

Another key hospital metric has also been rising in recent weeks: an average of 0.92% of last week’s emergency room visit had COVID-19 per July 28, up from 0.51% through June 28.

The new numbers come after months of largely easing COVID-19 trends nationwide since the last wave of infections over the winter, and again mark the biggest percentage increase in these key indicators of the virus since December.

“US COVID-19 rates remain near historic lows after 7 months of steady decline. Early indicators of COVID-19 activity (emergency department visits, test positivity, and effluent levels) preceded an increase in hospitalizations seen in the past week,” CDC spokeswoman Kathleen Conley said in a July 25 statement.

Conley said virtually all counties are “low” COVID-19 hospitalization levelsbelow the thresholds at which the CDC recommends additional precautions to slow the virus.

Are we seeing a summer spike?

While indicators of the virus are now clearly rising nationally, hospital admissions remain far below the levels recorded at this time last year.

Previous summer waves also saw steeper increases compared to what has been seen so far this year. The US has an average of 1,729 more hospitalizations per week compared to a month before.

In 2022, admissions peaked during the summer with 44,728 admissions in the week of July 23, 2022, after a wave of Omicron infections it burdened some hospitals. This was almost 12,000 more admissions compared to a month before.

In 2021, a sharp increase driven by the Delta variant increased by 20,029 more hospitalizations from June to July, reaching 32,850 admissions until July 24, 2021.

“The United States has seen increases in COVID-19 over the past three summers, so it’s not surprising to see an increase,” Conley said.

Projections have varied as to what the coming months will hold.

An ensemble of academic and federal modelers said last month that “the main period of COVID19 activity is expected to occur in late fall and early winter over the next 2 years, with median incidence peaking between November and mid-January.”

They cautioned that there were significant differences between models within the group, with some teams projecting a further smaller peak elsewhere in the year.

Is a new variant to blame?

Unlike previous waves, no single strain has yet emerged this summer to dominate infections nationwide.

Instead, the CDC latest projections estimates that a mix of descendants from the XBB strain that first led to infections last winter are now competing around the country.

Most prominent among these XBB subvariants are infections grouped as the XBB.1.16, XBB.1.9.1, XBB.2.3, XBB.1.6, or EG.5 strains, each accounting for between 10% and 15% of infections on national plan.

Experts had earlier highlighted EG.5 as one of the fastest growing genera worldwide. EG.5 is a descendant of the XBB.1.9.2 variant with an additional mutation that may help it outcompete other strains.

“At this time, the CDC’s genomic surveillance indicates that the increase in infections is caused by strains closely related to the Omicron strains that have been circulating since early 2022,” Conley said.

It comes as health authorities have been scrambling to prepare for a new round of COVID-19 vaccinations this fall.

Updated vaccines are expected to be available in late September, the CDC said earlier this monthaccording to the FDA requested that drug manufacturers are starting to produce new formulations targeting these kinds of XBB strains.

Public distribution of current supplies is due to wind down this week ahead of the update, which will also mark the transition to a traditional commercial market for vaccines.

However, the CDC says current supplies of shots will still be sent until September in “extraordinary” situations.

“While many individuals may wait to receive a COVID-19 vaccine until the updated version is released, as it is expected to provide more robust protection against currently circulating variants, certain individuals may need or desire a COVID-19 vaccine ahead of the expected release of the updated vaccine in the fall,” the agency said.