Officials with the two largest health care systems in Maine — Northern Light Health and MaineHealth — held a joint news conference Nov. 4, raising an alarm about how the respiratory virus is stressing hospital capacity. The problem has worsened over the past two weeks, they said.

Barbara Bush Children’s Hospital is part of the MaineHealth network. Northern Light Health officials also said that pediatric elective surgeries could be postponed in that network’s hospitals, although that option wasn’t currently on the table.

Caroline Cornish, a spokeswoman for Barbara Bush Children’s Hospital at Maine Medical Center, said that it’s not yet determined which surgeries could be delayed.

Hospital officials are working to free up capacity in many ways, such as moving some older pediatric patients to adult wings.

Ottolini said all 87 pediatric beds at the children’s hospital are filled up — although not all are due to respiratory illness — the driving force behind the rise in pediatric hospital admissions is RSV.

It’s the same dire situation at Eastern Maine Medical Center in Bangor, where almost all of the 37 pediatric beds are full, hospital officials said. There is no official state count for RSV, as the virus is not routinely tested for.

RSV is not tested for very often because unlike influenza and COVID-19, there is not a vaccine or effective medication for the RSV virus. So a test result does not change how to treat the disease. Scientists are working on an RSV vaccine, and it’s possible one could be developed within the next few years, federal officials have said.

Respiratory syncytial virus, or RSV, is a common virus that typically circulates each winter. In older children and adults, infections result in mild symptoms similar to the common cold — runny nose, cough and congestion. But in very young children, babies and toddlers, it can cause more severe breathing problems and lead to pneumonia.

RSV is most dangerous for infants under a month old. When it reaches the point that children have difficulty breathing, hospitalization is sometimes necessary, and those who have fallen ill can be given supplemental oxygen or, in very rare cases, placed on a ventilator.

Dr. Jonathan Wood, pediatric intensivist with Northern Light Eastern Maine Medical Center, said RSV usually peaks in December or January, so to see so many cases in October and early November is concerning. Public health experts have said that the COVID-19 pandemic has upended the seasonality of some diseases because children were not exposed to other virus and did no develop immunity.

“Everything has been turned upside down by the pandemic,” Wood said.

Dr. Dora Anne Mills, chief health improvement officer for MaineHealth, the parent organization of Maine Medical Center, said “we have a whole cohort of children under 3 years old who didn’t see RSV, didn’t get it. Suddenly, we now have a lot more RSV circulating.”

Influenza and other respiratory diseases have also been tamped down during the past two winters, as people wore masks and practiced social distancing. But now, mask mandates are no longer in place, and most people do not mask, even in indoor crowded places, which gives viruses more chances to infect people.

“I don’t know what we are going to see (this winter),” Wood said. “Maybe (RSV) will burn itself out. It’s really hard to say. We know children who get RSV can get it twice in one season. We know immunity is not great.”

Wood and others are worried that hospitals could be hit with a “tri-demic” of influenza, RSV and COVID-19 all at the same time, further straining hospital capacity.

Hospital officials said that people should get their flu and COVID-19 shots, practice good hygiene and stay home when ill. Parents who suspect their children have contracted RSV should first contact their primary care doctor before taking them to the hospital, as many times the child could be cared for at the doctor’s office or with a telehealth appointment.

Dr. James Jarvis, incident commander at Northern Light Health, the parent company of Eastern Maine Medical Center in Bangor and Mercy Hospital in Portland, said for people to “stay vigilant.”

“Wash your hands or use sanitizer frequently, cough or sneeze into your elbow or tissue or better yet wear a mask in all indoor public places,” Jarvis said. “Stay home when you are not feeling well, and get vaccinated against COVID-19 and influenza.”