The U.S. is seeing a late-summer spike in COVID cases, prompting some schools, hospitals and businesses to encourage — or even require — people to start masking up again.

The most recent Centers for Disease Control and Prevention data, from earlier this month, shows nationwide COVID hospitalizations increased by nearly 19% in a single week and deaths by more than 21%.

CDC Director Mandy Cohen said Tuesday that recently up to 10,000 people a week have been hospitalized with COVID. But, she added, that's far fewer than the 40,000 such hospitalizations a week the U.S. had at its highest point last August.

"We're in a much different and better place in August of 2023," she said. "We have stronger immunity and tools to protect ourselves, we have vaccines, at-home tests, effective treatments and common-sense strategies like washing your hands and staying away from people when you're sick."

Still, Cohen cautioned, COVID remains risky for people who are unvaccinated. The risk is especially high for unvaccinated individuals who haven't gotten the virus before and those who are older or have underlying health conditions. About 70% of hospitalizations are among those who are 65 and older, she added.

Public health officials have their eye on two new variants: The Omicron variant EG.5 — nicknamed Eris — has become dominant in the U.S., while BA.2.86 is starting to spread.

Early reports show Eris may be more transmissible than other variants, though it doesn't appear to cause more severe disease. And the CDC warned last week that BA.2.86 may be "more capable of causing infection" in people who have previously had the COVID virus or vaccines, though they don't believe it's causing more severe illness either.

All of that has driven some institutions around the country to reinstitute mask mandates, at least temporarily.

What schools, hospitals and politicians are saying

Morris Brown College, a historically Black college in Atlanta, announced last weekend that it would restrict gatherings and implement a mask mandate for two weeks due to reports of positive cases among students. Hollywood studio Lionsgate briefly required employees to wear masks on two floors of its five-story office.

The healthcare company Kaiser Permanente reinstated a mask mandate at its Santa Rosa, Calif., facilities after an uptick in patients testing positive. So did several hospital systems in New York state, including United Health Services, Auburn Community Hospital and Upstate Medical (both its university and community hospitals).

Upstate Medical University in Syracuse — the largest employer in central New York — announced in mid-August that it will require all staff, visitors and patients to wear masks in clinical areas for at least three weeks.

Dr. Stephen Thomas, an infectious disease physician and professor of medicine at the institution, told Morning Edition that the mandate was triggered by trends observed in recent weeks.

Authorities there have been following metrics that include the number of patients admitted to the hospital either with or for COVID and the number of staff missing work due to illness. They also monitor the region's wastewater testing program, which showed levels of the virus "dramatically increasing" and revealed that the EG.5 variant is circulating in the community.

Thomas says the combination of those factors prompted the decision to mandate masks — and it already appears to be helping.

"Once the notification went out, within an hour we were kind of doing the walkaround and implementation was very very quick," Thomas said. "People didn't really seem to think twice about it. There are always outliers, there are always people that are asking questions about the data and the science and does universal masking make a difference. But we try to communicate that universal masking, in healthcare settings, the data is very clear: It reduces transmission."

Some places are strongly encouraging people to return to masking, even if they're not requiring it.

The Talladega City School district in Alabama is urging students to wear masks, writing in a Facebook post that "this is not a mask mandate, but a general encouragement to be more conscious of our health." Elsewhere in the state, Kinterbish Junior High School is asking students, staff and visitors to wear masks due to rising case counts.

Other politicians are pledging expressly that they will not bring back mask mandates.

Illinois Gov. J.B. Pritzker recently dismissed rumors that his administration was discussing the possibility. Mississippi Gov. Tate Reeves said this week that his state will "not return to widespread masking or COVID rules," despite a rise in cases, adding that "people have a right to make their own decisions."

His statement also referenced a "pandemic of fear stoked by 'the expert class'' and "pronouncements ... from the Biden/Fauci administration," underscoring how much public health precautions have become politicized.

Former President Donald Trump — the frontrunner in the 2024 Republican primary race — also weighed in this week.

He released a campaign video on X (formerly Twitter) slamming the "fear mongering" of "COVID tyrants" and pledging "we will not comply" with school shutdowns, lockdowns or mask and vaccine mandates. If reelected, he said, he will cut federal funding to schools, airlines and public transportation systems that impose mask or vaccine mandates.

Notably, his administration recommended strict social distancing measures when the pandemic began in 2020.

What to know if you're on the fence

There's plenty of data to prove masks are effective at reducing COVID transmission when worn correctly. But in the absence of federal and state mask mandates, the question of whether — and when — to wear one is largely a personal decision.

Experts have told NPR in recent months that people should weigh how much risk they're willing to tolerate and modify their behavior as things change, including as cases rise.

For example, you may want to mask up in crowded settings, while traveling, if you're immunocompromised or if the person sitting near you seems sick. Some suggest getting in the habit of bringing a mask with you, just in case you need to make an impromptu decision.

And many are quick to point out that masking isn't the only step you can take to protect yourself.

Vaccines in particular are really powerful at preventing severe disease, and a new version could be available soon. A CDC advisory committee is meeting to discuss an updated booster on September 12.

The broadcast interview was produced by Julie Depenbrock.