(NEW YORK) — COVID-19 hospitalizations are continuing to climb in the United States, according to data from the Centers for Disease Control and Prevention.

For the week ending Sept. 9, hospitalizations increased 7.7% from 19,068 to 20,538 weekly hospitalizations.

This marks the first time COVID hospitalizations have surpassed 20,000 since mid-March, when the figure hit 20,170.

However, COVID figures are at relatively low levels overall compared to the peak of the omicron wave in winter 2021-22 when weekly hospitalizations hit 150,674 the week of Jan. 15, 2022.

Although increasing, the number of weekly hospitalizations remains less than hospitalizations at the same time in previous years. At the same period throughout the pandemic, weekly hospitalizations sat at 24,504 in 2020, 80,166 in 2021 and 31,571 in 2022.

“Hospitalizations [are] still a fraction of where we were in last winter and last summer,” Dr. Peter Chin-Hong, an infectious diseases specialist at the University of California, San Francisco, told ABC News. “I think it’s not surprising, but it’s still not like before — in terms of a surge — overwhelming resources. However, it is a siren call for the winter, when we have other things that cause people to go to hospital as well.”

He said with other viruses, including flu and RSV, expected to uptick this fall and winter, the health care system could be really strained if COVID hospitalizations keep increasing.

“If you bring too many people together and hospitalize them, it really strains the system and makes it hard for people who have other conditions to come into the hospital,” Chin-Hong said.

Additionally, 2.3% of all deaths in the U.S. last week were linked to COVID-19, according to CDC data. Although deaths have increased over the past few weeks, they still remain at their lowest levels since the pandemic began.

It comes as an updated COVID vaccine for everyone aged 6 months and older becomes more available across the country.

The updated vaccines, formulated by Pfizer-BioNTech and Moderna, are formulated to target variants that are currently circulating, which are related to XBB — an offshoot of the omicron variant.

Recent data has indicated the updated vaccines could offer additional protection against currently circulating variants and especially protect against severe disease and death, particularly for those who are elderly or immune compromised.

Data published from Moderna showed its updated vaccines generated a nearly nine-fold increase in antibodies against the newer subvariant BA.2.86 in a lab-based study.

There are about 14 cases of BA.2.86 in the U.S., according to the open global genome sequencing database GISAID. it does not appear to cause more severe disease.

There are at least 19,000 sites nationwide that have received the updated vaccines, according to ABC News medical contributor John Brownstein.

Chin-Hong said the vaccine could help stem any potential surge, but that it depends on how many people get the new vaccine and how quickly they get it.

“That’s kind of the interesting thing, we are predicting what will happen in winter, yet the active actors in the play are, you know, haven’t performed yet, which is people’s behavior in terms of getting the vaccine,” he said.

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