The first shot that protects all infants against respiratory syncytial virus, or RSV, won the backing of the Centers for Disease Control and Prevention on Thursday.

RSV is the leading cause of hospitalization among infants in the U.S. The shot, branded under the name Beyfortus, provides families with a simple option to protect their babies during the respiratory virus season.

The CDC’s panel of independent advisors unanimously recommended AstraZeneca and Sanofi‘s shot, also called nirsevimab, after reviewing the data in an hourslong meeting Thursday afternoon.

CDC Director Dr. Mandy Cohen accepted the advisors’ recommendation Thursday evening. She called on families to take advantage of the new drug.

“As we head into respiratory virus season this fall, it’s important to use these new tools available to help prevent severe RSV illness,” Cohen said. 

“I encourage parents of infants to talk to their pediatricians about this new immunization and the importance of preventing severe RSV,” she said. 

The CDC said Beyfortus should be available this fall. AstraZeneca and Sanofi are prepared to roll the shot out before RSV season and do not foresee any challenges meeting demand, a Sanofi spokesperson said.

Dr. Sarah Long, a CDC panel member, described Beyfortus as a milestone. 

“This is the very first antibody protection against a remarkably remaining burden of disease in children,” said Long, a professor of pediatrics at Drexel University. 

“Parents should be very, very much relieved that they won’t have to be concerned about the likelihood that their child could be hospitalized with RSV disease,” she said.

Most insurance plans will be required to cover the shot at no cost to consumers due to requirements under the Affordable Care Act. The shot has a list price of $495. 

Though Long described the shot as a breakthrough, she said the CDC panel is “extremely disappointed” by the price set by Sanofi and AstraZeneca.

It could potentially take months for some insurance plans to update their policies to comply with the requirement. 

The CDC advisors also voted unanimously to include the shot in the federal Vaccines for Children Program, which provides shots to kids whose families are struggling financially. The program provides immunizations to about half of the nation’s children.

Beyfortus works like a vaccine, but the shot is considered a drug, not a vaccine, because it is an antibody injection. Vaccines prepare the body’s immune system to release antibodies that fight viruses, while Beyfortus injects these antibodies directly into the bloodstream.

Infants younger than 8 months entering their first RSV season would receive one dose. Kids 8 to 19 months who face an increased risk from the virus would receive another dose in their second RSV season. 

Another option, called palivizumab, is already on the market but it is primarily used for pre-term babies and those with congenital heart and lung conditions. It is also more difficult to administer because infants have to receive a shot monthly during RSV season.

Beyfortus, on the other hand, is broadly available for all infants regardless of whether they have a health condition. It is also administered as a single dose to protect babies during the entire RSV season.

Beyfortus was up to 75% effective at preventing lower respiratory tract infections that required medical attention among infants and 78% effective at preventing hospitalization, according to an FDA review.

The FDA did not identify any safety issues when it reviewed Beyfortus. Some monoclonal antibodies have been associated with allergic reactions and skin rashes.

RSV kills nearly 100 infants every year, according to a study published in the medical journal JAMA Network Open in 2022. It is also the leading cause of hospitalization among children less than a year old, according to a study published in the Journal of Infectious Diseases.

Children’s hospitals were overwhelmed last year by a surge of RSV infections at the same time that flu and Covid were also circulating.

The wave of illness strained hospitals so much that they called on the Biden administration to declare a public health emergency in response. The White House ultimately did not declare one.