After weeks of increasing COVID hospitalizations, is the summer peak over?

After weeks of increasing COVID hospitalizations in the United States, the number of patients seems to be trending downward, and experts say the summer peak might be over.

Weekly hospitalizations decreased 3.1% from 19,691 to 19,079 for the week ending Sept. 23, according to data from the Centers for Disease Control and Prevention.

The figure is close to levels seen in March of this year and marks the second straight week of declines, data shows.

Previously, hospitalizations had increased from late July to early September, even surpassing 20,000 weekly patients last month, data showed.

Public health experts told ABC News that it looks like the summer peak is over and all COVID metrics should be on the decline ahead of traditional respiratory virus season.

"Signs point to the fact that the increase that we saw late summer is now subsiding," said Dr. John Brownstein, an epidemiologist and chief innovation officer at Boston Children's Hospital and an ABC News contributor. "That's not so unexpected given that we've seen previous seasons where you get this smaller summer peak, possibly driven by people being indoors, kids coming back to school post-vacation."

Experts said some of the hospitalizations were due to people who were in the hospital for other reasons and tested positive for COVID-19 incidentally.

"When we look at our numbers at NYU, we do both -- look at numbers of patients who are incidentally diagnosed... but we also look at our numbers for people who have been admitted for COVID-related pulmonary issues," Dr. Dana Mazo, a clinical associate professor of medicine at NYU Grossman School of Medicine, told ABC News. "And we did see an increase in both of those groups."

Deaths are still trending upward, according to CDC data, but experts say they are a lagging indicator and should decline -- just as hospitalizations did -- before long.

With the end of the public health emergency in May, the CDC stopped sharing data about COVID-19 transmission levels and community levels and used COVID-related hospital admissions as the primary metric to measure virus spread.

Experts say hospitalizations are still one of the best metrics to measure the severity of COVID because they have the greatest public health impact.

Dr. William Schaffner, a professor of preventive medicine and infectious diseases at Vanderbilt University Medical Center, said the number of cases doesn't tell public health officials how severe a person's infection is or how easily it was treated.

"There are a lot of people who are not testing anymore," he told ABC News. "Our testing intensity has diminished... But that measure is not reliable because early on, we knew about every test and whether it was positive or negative. Now, we don't have that kind of a handle on how frequently people are having minor infections."

Brownstein added, "There once was a point when cases were actually an important indicator. They're less so now just because people are just not testing, people recognize what they need to do when they're ill, regardless of what virus is causing that illness. Hospitalizations still represent our best bet right now."

Experts say not to become complacent because fall and winter have traditionally come with surges and recommend all Americans aged 6 months and older receive the updated COVID vaccine.

The Food and Drug Administration and the CDC say the updated vaccine more closely matches currently circulating variants and protects against severe disease and hospitalization.

In addition to the updated COVID vaccine, officials are also recommending Americans receive the flu vaccine and the new RSV vaccine for those aged 60 and older.

"Flu is still part of the routine annual vaccines that everyone is eligible for and then RSV is, of course, newer and that will be much more guided toward those who are in higher risk groups," Brownstein said. "Making sure we get as many people protected will help alleviate any pressures, we're going to feel on our health care systems heading into the winter, which is something we felt across all health care systems, especially in the pediatric population."