This year’s COVID surge may just be starting. Here are four ways to protect yourself.

In Rhode Island, Dr. Leonard Mermel, medical director of epidemiology and infection control at Lifespan, which runs hospitals across the state, says the number of weekly positive tests for respiratory viruses has already surpassed January 2023 levels.

“I think generally people have let their guard down,” he said. “So we have suboptimal uptake of vaccines that will reduce the risk of getting infected and severity of infection. There’s probably more social gathering indoors without any sort of respiratory protection than previously.”

In Worcester, Dr. Robert Klugman, medical director of Employee Health Services at UMass Memorial Medical Center, said emergency room visits and hospitalizations for COVID have tripled over the last three weeks. But they remain below what they were last year at this time. Meanwhile, the number of employees who have called in sick has also nearly tripled – “numbers we haven’t seen for several years.” Klugman notes that health care workers skew young and healthy, which means few of them are likely to end up hospitalized. That same youth may make them less likely to take precautions that would have prevented them from testing positive and having to miss work in the first place.

“Omicron was bad,” he said “This is worse. We’ve had, some days, 40 to 50 people calling in with COVID. We haven’t seen numbers like this since ‘21.”

Dr. Larry Madoff, medical director for the bureau of infectious disease and laboratory sciences at the Massachusetts Department of Public Health, said COVID and flu infections rose at “very brisk levels” over the last week.

“Anecdotally, all of my colleagues are very busy,” he said.

But he said a surge is “not unusual this time of year.”

Last year, hospitalizations peaked the week after Christmas with close to 24 percent of emergency room admissions related to acute respiratory illnesses, including flu and COVID. That was down from 2022, when close to 30 percent of ER admissions were caused by acute respiratory disease.

“Historically, influenza-like illness has peaked post-Christmas. In the last couple years, COVID rates [have been] similar, which may mean they are settling down into the seasonal patterns we see with other viruses,” he says.

Coming into the holiday break this year, the week ending Dec. 23 — the most recent week for which state data are available — the number of emergency room visits for respiratory infections was substantially lower — 16.7 percent.

“It’s lower because we have more vaccine and infection derived immunity,” said Dr. Cassandra M. Pierre, an infectious disease physician and the associate hospital epidemiologist at Boston Medical Center. “Even though we had a fair amount of immunity last year, we have even more now. So that’s one factor we have that plays in our favor.”

Still, this year’s COVID surge may just be getting started.

“I am not a forecaster, but I think we have yet to see our peak,” she said. “And my thought is that we’ll see high levels of transmission, at least until the end of January is my guess.”

If you’re feeling a little less casual than your maskless colleagues, or the public at large, here are some things you can do to protect yourself:

“Even though we are kind of in the midst of respiratory virus season, it is really not too late,” said BMC’s Pierre. “Protect yourself, because we still have a few more weeks of this intense rise ahead of us.”

Test at the first sign of symptoms. And, if you are at high risk, consult a doctor about medication.

“COVID vaccinations are disappointingly low – it will protect you against severe disease,” said Madoff of the state public health department. “But therapeutics are also being underutilized for both flu and COVID. People at higher risk should get treated with antivirals as quickly as possible.”

Since the JN.1 variant is more contagious, it takes fewer virus particles and less time for someone to become infected, said Klugman. High-ceiling spaces, like supermarkets, are safer than bars or bistros, because they have room for a greater volume of air, which allows it to circulate and lessens your chance of inhaling infectious particles.

The same is true of offices. Klugman notes that, in offices, coworkers are breathing the same air, and are at risk of infecting one another. Masks, particularly in cramped spaces, are a good idea, he said.

Mermel suggests minimizing large indoor social gatherings as much as possible as we move into peak season. But there are ways to minimize the risks. In addition to masking, vaccinating and testing, finding ways to ensure air circulation can reduce the risk of transmission. Most hospitals, he notes, have strict guidelines regarding airflow, with the capacity to ensure air exchange so that viral particles can be quickly removed. At home, opening windows can make a difference.

Klugman says the incubation period for COVID has fallen in recent years, and anyone infected on New Year’s Eve, is likely to see the first symptoms in 48 to 72 hours. Mermel said it usually takes three to four days.

Both note that plenty of people exposed to COVID might not see any symptoms at all – and should test if they are concerned about exposure and worried about getting others sick. Matthew Fox, a professor in the departments of epidemiology and global health at Boston University, notes it can take anywhere from a few days to, in rare cases, as long as three weeks. Most will see symptoms within the first week.

Adam Piore can be reached at adam.piore@globe.com.