Coronavirus infections continue to increase across the greater Washington region, with hospital beds filling up, nursing homes returning to visitor restrictions and outbreaks of the virus hitting schools as they return to in-person learning.

Physicians and public health experts say the next few weeks will be critical in determining whether the latest surge is plateauing — and if masking and social distancing is keeping the spread of the virus at bay.

“We’re in a tenuous position, not just going into Labor Day but also going into school opening,” said Nilesh Kalyanaraman, the health officer in Anne Arundel County. “It’s going to bring all the kids, all the teachers and all the staff back. So it’s going to be really critical to keep an eye on this just because of how much is changing in the next week.”

Lynn Goldman, the dean of George Washington University’s Milken Institute of Public Health, said the optimism she felt in July — when cases were at some of the lowest points they’ve been during the pandemic — has given way to resignation.

“I think that we’re more learning to live with a certain amount of this,” she said.

That’s why public health experts continue to emphasize vaccination as the best protection against the coronavirus, including the highly contagious delta variant, despite some breakthrough cases.

“You are 10 times safer vaccinated than if not, but still not absolutely safe,” Goldman said. “It’s still way too much in the way of hospitalizations and death even though rates are a lot lower than they were last year.”

The seven-day average of new cases in the region was 4,767 on Friday, a number that has been steadily rising since early June and which hasn’t been seen in the region since early February, the tail end of the pandemic’s last surge. In the past week, the number of cases in the three jurisdictions went up between 10 percent and 14 percent.

But the seven-day average of coronavirus deaths in the region is 30, much lower than the mid-80s it hit at that same time in early February — which officials attribute to the availability of coronavirus vaccines.

As of Friday, 61.8 percent of Maryland residents, 57.6 percent of Virginians and 57.5 percent of Washingtonians were fully vaccinated, according to The Washington Post’s tracker.

All three jurisdictions have requirements that at least some of their government employees get vaccinated or face regular coronavirus testing. Some hospital systems and other private businesses have implemented similar measures.

While D.C. is requiring everyone, regardless of vaccination status, to wear a mask in indoor public spaces, Maryland and Virginia leaders have shied away from requiring masking. Maryland has left the decision up to local leaders; Montgomery and Prince George’s counties, the state’s two largest jurisdictions, both have required indoor masking after the latest surge began.

Whether schools become hot spots for outbreaks is one factor public health officials are watching closely. D.C., Virginia and the largest districts in Maryland are requiring masking in schools — which Anne Arundel’s Kalyanaraman described as a key to protecting students under 12 who are not eligible for vaccines.

Of the 25 ongoing outbreaks reported in Virginia, as of Thursday more than half were in day care, pre-K or public schools, according to the state tracker. An outbreak was associated with at least one death.

Nathaniel Beers, a pediatrician at Children’s National Hospital and former head of special education for D.C. public schools, said two years ago few parents would think twice about sending kids to school with the sniffles or a cough, but the pandemic changed all that.

“That’s an added complexity for families,” he said in an interview late last month. “But if we are going to keep kids safe we have to have a lower threshold for keeping them home.”

With a fever, shortness of breath or loss of taste or smell — what he called “the big three” — Beers advised parents to get their kids tested or consult their pediatrician about what to do.

Although vaccinated children who are exposed to the coronavirus can attend school safely, according to Centers for Disease Control and Prevention guidelines, Beers said most school districts in the greater Washington region require unvaccinated kids who are exposed to quarantine. And if they have symptoms, testing is recommended.

As school started last week, Baltimore school district officials announced that high school athletes will be required to get vaccinated to participate in winter and spring sports. The mandate to be fully vaccinated will take effect on Nov. 1; the city schools are not requiring vaccination for fall sports because the season is underway.

Baltimore Mayor Brandon Scott said he supports the school district’s decision.

“I had to have vaccines to go to school, let alone to play sports,” he said.

The decision comes weeks after the city instituted an indoor mask mandate. With more than 56,000 confirmed cases, the city’s case count is up 87 percent from a month ago, Scott said.

Baltimore City Health Commissioner Letitia Dzirasa said the city is averaging about 87 cases per day and, like the rest of the nation, the majority are the delta variant.

Even though the positivity rate in the city is around 3 percent, Scott said other indicators, including the number of full hospital beds, show that “it is clear we are still battling this pandemic.”

That’s lower than the statewide positivity rate, which ranged from 4 to 7 percent in the week ending Aug. 31, federal data show.

Hospitalizations have been increasing in much of the region; Maryland and Virginia both saw a 15 percent increase in coronavirus hospitalizations in the last week, although D.C. saw a 1 percent decline in that same time.

But Steve Motew, a physician and chief of clinical enterprise for Inova Health System, which includes five hospitals in Northern Virginia, said the high community spread in Virginia is not leading to as many hospitalizations as previous surges because of vaccinations.

“The ICU [beds] are not filled as exclusively with covid patients as they were before,” he said. One day this week there were 10 coronavirus patients in the ICU across the Inova system — all of whom were unvaccinated, including eight on ventilators — a small fraction of the nearly 300 ICU beds available.

Overall coronavirus admissions have been fairly stable over the past three to four weeks, Motew said, with a census of 50 to 70 patients a day. The high was 450 last year.

Admissions also appear to have plateaued at MedStar Washington Hospital Center, where out of more than 800 beds, about 35 to 40 patients are being treated for the coronavirus every day for the past week or two, said Glenn Wortmann, the hospital’s chief of infectious diseases.

That’s up from June, when there were about 10 such patients a day, but down from the peak of 190, he said.

He called the start of school “the big unknown” when it comes to the pandemic.

“What nobody knows, when you’re at the peak, you don’t know you’re at the peak until you start to go down. The next two weeks are going to be very important,” he said.