The American Academy of Pediatrics expanded its recommendations for immunization against respiratory syncytial virus (RSV) to include more children entering their second RSV season, citing evidence that certain medical conditions continue to put young children at a higher risk for severe disease.

The expansion includes children aged 8 months through 19 months entering their second RSV season who have congenital heart disease, certain lung or neuromuscular conditions, or have Down syndrome or certain chromosomal conditions associated with a higher RSV risk, and those born before 32 weeks of gestation who do not need ongoing medication or support.

The updated guidance for second-season immunization also includes children with certain forms of cystic fibrosis, chronic lung diseases requiring recent medical support, and all Native American and Alaska Native children.

High-risk children should receive a second dose “regardless of whether their mother was immunized when they were pregnant and regardless of whether or not that infant received an RSV immunization during their first RSV season,” said Andrew Racine, MD, PhD, president of the AAP, during a press briefing announcing the recommendations.

The changes reflect growing evidence that although the likelihood of hospitalization for RSV generally declines after the first year of life, some children remain at a substantially higher risk.

Children with chronic conditions affecting multiple respiratory, cardiovascular, or gastrointestinal organs had more than twice the rate of hospitalizations during their second RSV season than during their first season, according to the AAP’s accompanying technical report.

For infants entering their first RSV season, the AAP recommends a monoclonal antibody unless the mother received an RSV vaccine during pregnancy.

RSV Season Is Lasting Longer

The expanded recommendations come as other major medical organizations have updated their guidance for the 2026-2027 respiratory virus season, with some changes reflecting shifts in the timing of RSV circulation.

The American College of Obstetricians and Gynecologists (ACOG) extended the recommended window for the maternal RSV vaccine ABRYSVO from September 1 through March 1, rather than ending on January 31.

“We made this change because the RSV disease season is now occurring later in the spring, and it is also more severe than it used to be,” said Christina Davidson, MD, chief medical officer at ACOG. “The extension of the eligibility window will help provide pregnant patients and their infants with additional protection.”

Pregnant people should receive the vaccine between 32 and 36 weeks of gestation, provided delivery is not expected within 2 weeks. If a patient does not receive the vaccine, or if the infant is born within 14 days of vaccination, the newborn should receive a monoclonal antibody for RSV.

First-Season Protection Remains the Priority

Despite the expansion of second-season recommendations, the AAP’s guidance emphasized protecting infants during their first RSV season.

Nirsevimab reduced hospitalization risk by as much as 93% in an independent evidence review conducted by the Vaccine Integrity Project, part of the University of Minnesota’s Center for Infectious Disease Research and Policy. The AAP’s accompanying technical report found that most infants hospitalized with RSV had no underlying high-risk medical condition.

Clinicians should emphasize to families that changes in RSV patterns and evolving evidence reinforce the consensus among medical organizations on the benefits of a second dose, said Sarah Nosal, MD, president of the American Academy of Family Physicians.

“As federal guidance evolves, the science behind vaccines remains strong,” Nosal said.

The second-dose RSV recommendations are “grounded in the latest evidence, informed by public health experts, and shaped by what family physicians are seeing every day in their patients,” Nosal said.

Lara Salahi is a health journalist based in Boston.