CDC panel recommends RSV shot for babies

The Centers for Disease Control and Prevention's vaccine advisory committee voted on Thursday to recommend infants receive a newer monoclonal antibody shot for respiratory syncytial virus (RSV).

The Advisory Committee on Immunization Practices (ACIP) voted 5-2 to recommend clesrovimab, made by Merck, for infants 8 months and younger who are not protected by a maternal vaccine.

In a second vote, the committee voted unanimously to update the resolution for the federal Vaccines for Children program to include details about the newly approved antibody shot. About half of all U.S. children are eligible for free or low-cost vaccines.

It marks the first vote of the panel since Health and Human Services Secretary Robert F. Kennedy Jr. dismissed the entire panel and appointed his own hand-selected members.

Currently, RSV vaccines are recommended for pregnant women between 32 and 36 weeks of pregnancy to pass on protection to a fetus, which should last throughout their first RSV season.

For babies 8 months and younger born to mothers who did not receive a maternal RSV vaccine, monoclonal antibody shots are available.

Monoclonal antibodies are proteins manufactured in a lab and mimic the antibodies the body naturally creates when fighting an infection. They do not activate the immune system as would occur with vaccination. The shot is also recommended for a small group of children from 8 months old through 19 months old who are at increased risk for severe RSV.

During the first day of the meeting, on Wednesday, Dr. Georgina Peacock, director of the Immunization Services Division in the CDC's National Center for Immunization and Respiratory Diseases (NCIRD), shared CDC data showing 57% of infants born between April 2024 and March 2025 were protected from RSV by maternal vaccination or receipt of nirsevimab, one of the currently available antibody shots.

Dr. Cody Meissner, one of the new ACIP members, described the vaccine and antibody data, showing its real-world impacts as a "truly spectacular accomplishment."

"People should understand this is a truly spectacular accomplishment and will have enormous impact on public health," he said.

Another ACIP member, Retsef Levi, expressed some skepticism, saying he wanted to see more data on how efficacy for the maternal vaccine changes over time, adding that RSV is a "tricky" virus that "fools interventions in unexpected ways."

In response, Dr. Adam MacNeil of the NCRID said vaccine efficacy does wane over time, but the maternal RSV vaccine protects newborns and infants when they're at their most vulnerable, before they develop more robust immune systems.

The votes comes after the group announced on Wednesday it would review the current childhood immunization schedule.

Martin Kulldorff, the ACIP's new chair, said two new work groups would be established, one focusing on the cumulative effects of children and adolescents receiving all recommended vaccines on the schedule and another reviewing vaccines that haven't been examined for more than seven years.

The latter group may discuss whether the hepatitis B vaccine is necessary at birth before a baby leaves the hospital, according to Kulldorff.

"The number of vaccines that our children and adolescents receive today exceeds what children in most other developed nations receive and what most of us in this room received when we were children," Kulldorff said.

The American Academy of Pediatrics put out a video on Wednesday, saying immunization policy through ACIP is "no longer a credible process" and that it will continue to publish its own vaccine recommendations for children.

In the morning, CDC staff presented data on COVID-19 vaccines, showing safety and efficacy as well as a reduction in hospitalizations and deaths.

For the 2024-25 updated COVID vaccine against emergency department and urgent care encounters, the CDC found 79% effectiveness for children between nine months and 4 years old, 57% effectiveness among children between five and 17 years old and 34% effectiveness for those aged 18 and older.

Kulldorff asked where the data shows COVID-19 vaccine effectiveness from placebo-controlled trials. Dr. Adam MacNeil, from the CDC's National Center for Immunization and Respiratory Diseases (NCIRD), said the CDC's evaluation of effectiveness came from real-world data.

"Randomized clinical control trials are not necessarily comparable to what we're currently seeing with the vaccine," MacNeil said. "Where we're trying to now monitor is the real-world impacts of these vaccines as opposed to clinical trial data, which was certainly extensively documented."

The ACIP members also discussed questions about potential safety signals surrounding the COVID vaccine, with the CDC determining that myocarditis and pericarditis -- inflammation of the heart muscle and the sac around the heart, respectively -- are still risks, but no other risks have been found.