A rise in cases of respiratory syncytial virus (RSV) is unfolding just as COVID-19 infections are increasing among children.

There has been a rise in RSV cases since early June, with a notable spike in the past month, U.S. Centers for Disease Control and Prevention data show, The New York Times reported. The sudden increase in cases is unusual because RSV typically begins to spread in the fall. Even more troubling, more children are showing up in hospitals with COVID-19 as the highly contagious delta variant takes over the country.

"After many months of zero or few pediatric COVID cases, we are seeing infants, children, and teens with COVID pouring back into the hospital, more and more each day," Heather Haq, M.D., a pediatrician at Texas Children's Hospital in Houston, said in a series of Twitter posts.

Patients have ranged in age from 2 weeks to 17 years, and some have also had COVID-19 pneumonias, according to Haq, chief medical officer for the Baylor College of Medicine International Pediatric AIDS Initiative at Texas Children's, The Times reported.

"We are on the front end of a huge COVID surge," Haq wrote. "We are now having winter-level patient volumes of acutely ill infants/toddlers with RSV, and I worry that we will run out of beds and staff to handle the surge upon surge."