Coronavirus restrictions last winter kept cases of respiratory syncytial virus (RSV) low among children, but cases are rapidly on the rise. Frontline health care workers are concerned about a potential surge in children infected with both RSV and Covid-19 as the viruses spread across the country.

Your top resources for Covid-19 readiness

An out-of-season RSV surge

According to the New York Times, RSV is a common respiratory illness among children that typically causes mild cold or flu-like symptoms, such as a fever, runny nose, or congestion. But in some children, especially those younger than two years old, RSV can lead to severe complications, such as pneumonia or bronchitis.

Usually, RSV, which is highly contagious, spreads during the colder months and peaks in February, the Times reports. However, coronavirus restrictions last year disrupted the virus's usual pattern, with CDC data indicating that RSV and other seasonal infections hit historic lows last winter amid masking requirements and social distancing.

However, as states began to reopen and ease up on coronavirus restrictions, cases of RSV in young children began to rise rapidly across the country. 

For instance, at the Children's Hospital of Philadelphia, doctors began to see a rise in RSV cases in May. RSV cases at the hospital have surged even more in the past eight weeks, according to Audrey John, chief of the hospital's division of pediatric infectious diseases.

"To put that in perspective, none of the children who were tested for RSV through the winter were positive," John said. "But in the last couple weeks we're up to one in four children who are getting tested are positive for RSV. That's a lot of virus out there."

In June, children's hospitals in other areas of the country, including Texas, Florida, and Louisiana, also reported spikes in RSV cases.

According to experts, this increase could result from children being more susceptible to the virus than they would typically be. According to an article in Time, babies who were born shortly before or during the pandemic may not have been exposed to the virus like they usually would of have been, meaning that they are more vulnerable to infection now.

For example, Pia Pannaraj, an infectious diseases specialist at Children's Hospital in Los Angeles, said the lack of widespread RSV last winter means that "babies up until about a year and a half or two years of life are at risk" as the virus surges now.

Children face potential co-infection with RSV and Covid-19

According to NPR, frontline health care workers say more children may be diagnosed with both Covid-19 and RSV as cases of both viruses continue to rise across the country.

For instance, Texas Children's Hospital in Houston reported that 25 out of 45 pediatric patients were diagnosed with both RSV and Covid-19—which officials said is "[a] hospitalization rate much higher than for either virus alone."

Currently, there is little data about how contracting both viruses affects patients and if a co-infection will make a patient sicker, NPR reports. But health officials are worried that young patients, who are not eligible to be vaccinated against Covid-19, will be at greater risk.

And given that many symptoms of RSV—such as coughing, a lack of appetite, excessive sleeping, and lethargy—are similar to symptoms of Covid-19, Pannaraj said parents and physicians "need to look out for both of those infections."

Pannaraj added that while there haven't been many reported cases of co-infection of RSV and Covid-19 so far, "that doesn't mean that it won't happen."

"In fact, we probably have to assume that it will happen," she said, adding that more co-infections will likely be reported within a few months.

How to reduce RSV risk

To reduce risk of RSV infection, according to the New York Times, doctors recommend people follow common disease prevention practices, such as frequent hand washing, avoiding crowded places, and keeping children at home when they are sick to reduce the risk of infection. Children over the age of two should also wear masks, and individuals who have cold or flu symptoms should avoid close contact with infants.

In addition, doctors can administer a drug called Palivizumab to children who are at high risk for severe cases of RSV, the New York Times reports. The drug is usually administered in five monthly injections during the winter, but due to the current surge in RSV cases, the American Academy of Pediatrics issued a statement earlier this month asking pediatricians to considering administering the drug to eligible infants right away. (O'Connor, New York Times, 8/24; Romo, NPR, 8/24; Ducharme, Time, 7/22)