Coronavirus case rates and hospitalizations in the D.C. region have continued to worsen in recent weeks, rising to levels not seen since last spring just days before some area school systems return to in-person classes for the new academic year.

“What’s concerning me is that while there are some signs that maybe COVID cases could plateau soon, [but] once school starts, they’re going to pick right back up again and we’re going to continue to see this large rate of increase in the cases,” says Amira Roess, an epidemiologist at George Mason University. “That’s really been on my mind a lot.”

Local data paints a concerning picture. Many key metrics — including the rolling average of new cases per day, the positivity rate of tests, and hospital utilization — have climbed back to levels last seen before the height of the vaccination campaign.

Northern Virginia, for instance, is adding an average of about 300 new cases per day, a rate not seen since mid-April, and ten times early July’s all-time low of 30 cases per day. In D.C., the new case rate hasn’t been as high as it is — 23.1 new infections per 100,000 people — since March. New case rates in Maryland are behaving similarly, reaching volumes not seen since this spring.

All jurisdictions in the D.C. region are experiencing “substantial” or “high” coronavirus spread, designations from the Centers for Disease Control and Preventions based on the agency’s calculation of the average weekly new case rate and the average weekly positivity rate for the locality.

While area hospital capacity isn’t currently overwhelmed, the surge is beginning to show up in hospital bed utilization. In Maryland, 630 beds currently hold COVID-19 patients, up from just over 100 earlier in the summer. In Virginia, 1,289 people are hospitalized with COVID-19 or suspected COVID-19, almost six times the number in early July. In D.C., hospitals are at about 86% capacity.

Some area hospitals didn’t see a single new COVID case in early July, but are now reporting as many as 20 per week, according to the Washington Business Journal.

The rising numbers are being fueled by the highly transmissible Delta variant, which is far more contagious than previous strains of the virus. Epidemiologists caution that people who are unvaccinated will almost certainly contract it. And while the D.C. region has high vaccination rates compared to other parts of the U.S., the full vaccination rate of the total population, including kids who aren’t yet eligible — 56% in D.C., 55% in Virginia, and about 60% in Maryland — is not enough to contain the Delta surge.

The surge is part of a massive national uptick in cases which is hitting communities with low vaccination rates in the South especially hard.

“While we are seeing an increase in cases, the rate of increase hasn’t been as steep as what we’ve seen in other parts of the country,” says Roess.

But she doubts that the D.C. region will be finished with this latest COVID-19 surge anytime soon.

“We would have had a chance of reaching the plateau sooner had it not been for the realities that we’re facing: people going back to school and work in very large numbers all at once, and a stagnating vaccination rate,” says Roess.

In a recent Post-Schar School poll, about 40 percent of workers said they are worried about coronavirus exposure at work. While many workplaces have pushed plans to return to the office back incrementally or indefinitely, others have forged ahead.

At Bloomberg Industry Group, at least six employees in Arlington and D.C. have tested positive after heading back to in-person work, the Washington Post reported earlier this month. “We’re all concerned about causing further cases in the D.C. area,” one journalist told the outlet.

Vaccination rates locally are increasing slightly, as local health departments scramble to find and vaccinate hard-to-reach people and those who remain cautious about taking the shot.

“We really need people who have not yet been vaccinated to get there,” said Dr. Danny Avula, the Virginia Department of Health’s vaccine coordinator, in a press call. “And some of that is going to happen. It’s going to happen because Delta is real and it is causing more infection. And as we see cases surge, that’s driving vaccination. We’re already seeing that in terms of our day in, day out vaccination numbers.”

In the meantime, lagging vaccination numbers coupled with the Delta variant could mean a challenging beginning to the school year, with infections and outbreaks in newly returned schools driving a continued rise in coronavirus cases overall. Roess expects the increase locally could last into the fall or early winter, a month or more after the beginning of the school year.

The precautions area schools have instituted, like mask mandates and vaccine requirements for staff, are helpful, Roess says, but they won’t completely stop school-related outbreaks.

“It’s really not a matter of if there will be outbreaks in schools at this point, it’s a matter of when will they have the outbreaks, when will classes have to go home to quarantine, how many are going to have to quarantine,” Roess says. “All indications are it’s going to be a very large number, a very large percentage of children who are going to be exposed.”

Roess hopes area school systems will rely on frequent, fast testing and contact tracing to keep the volume of school-related outbreaks down.

“We need testing to be done frequently and we need results to be turned around in a very timely manner in order to quickly identify positive individuals, especially asymptomatic positive individuals, and make sure that classes are sent home as early as possible following the identification of a positive individual,” she says. “If we can do that, I think we can get ahead of this, and we can avoid having hundreds of kids infected within a month of school starting. But that’s a tall order.”

Many local schools are currently planning to conduct some kind of surveillance testing, though plans vary. KIPP D.C. charter schools will test students and staff, and Montgomery County Public Schools said it plans to do so on a weekly basis (in practice, they are prioritizing elementary schools and the policy is unevenly applied). Fairfax County Public Schools, the region’s largest district, says it is developing a partnership to provide screening testing to students and staff. D.C. Public Schools will test 10% of students each week. Prince George’s County Public Schools will conduct testing “as needed.”

Local parents have also expressed concerns about children wearing masks correctly for a full school day and the possibility of infections developing in high-exposure settings like cafeterias.

Children rarely experience severe COVID-19 illness, but more children are getting sick as the Delta variant spreads. Last week, D.C. officials said children ages 5 to 14 account for about 10% of new infections. Nationally, that number is about 18%.

The hardship of staying home with children who’ve been exposed or gotten sick is a burden that will fall heaviest on families where parents don’t have the flexibility to work from home, Roess notes.

How successfully school systems are able to quarantine infected students, test staff and students for asymptomatic infection, and perform contact tracing will set the timeline for the fall surge. Roess’s best-case scenario is a heightened period of transmission for the first month or month and a half after schools return, which then would begin to taper off.

But in the absence of swift action from school authorities, she believes the region could see a “protracted increase” in cases.

“It is really quite possible that the pediatric ICU will also be full before we know it, because just like children in the South, our children are susceptible,” Roess says. “A lot of pediatricians are bracing themselves for something similar to what we’re seeing in the South occurring here.”

This story was updated to clarify Montgomery County Public Schools stance on testing.