(Bloomberg) -- Pfizer Inc.’s maternal vaccine to protect newborns against the sometimes fatal RSV virus can be administered across the US after the Centers for Disease Control and Prevention signed off on its rollout.

CDC Director Mandy Cohen on Friday endorsed the new shot Abrysvo in pregnant women at 32 to 36 weeks of gestation, following its recommendation by a panel of vaccine and health experts. 

“This is another new tool we can use this fall and winter to help protect lives,” Cohen said in a statement. “I encourage parents to talk to their doctors about how to protect their little ones against serious RSV illness.”  

The vaccines are already available in some locations in the US, and that’s expected to increase in the coming weeks, the agency said. Pfizer said in a statement Friday it has already begun distributing Abrysvo to pharmacies and doctors. 

The Food and Drug Administration approved the shot in August, yet with a warning that 5.7% of participants in a vaccine study had pre-term births, compared with 4.7% in a group that received a placebo.  

Pfizer is following Sanofi and AstraZeneca Plc’s preventive monoclonal antibody for newborns to market. Global sales for protection against Respiratory Syncytial Virus for both infants and older adults is expected to top $10 billion by 2032. Pfizer and GSK Plc had already received CDC recommendations for vaccines for those 60 and older. Moderna Inc. is also working on an injection for RSV using the messenger RNA technology that powers its Covid vaccine. 

Pfizer shares fell 0.5% to $32.69 at close of market in New York. 

Decades of Failure

After 60 years of failure to find protection against RSV, the race intensified last year when cases began spiking as Covid social-distancing measures faded. Some 2% to 3% of infants with RSV in the US are at risk of hospitalization, and up to 80,000 children under five end up being admitted each year due to complications related to the virus.

The recommendation “reinforces the wide-ranging impact vaccines can have, including helping protect infants immediately at birth from the potentially severe and life-threatening complications that can develop from RSV,” said Luis Jodar, Pfizer’s chief medical affairs officer for vaccines.

The company called insurance coverage for the shot the next “critical step” to ensure patients are vaccinated and said it anticipated plans would prioritize establishing coverage in the coming weeks. 

Pfizer will need to distinguish its maternal vaccine from the competition. It offers protection from the moment a baby is born and is lower in price than Sanofi’s antibody, which could help it take market share, Bloomberg Intelligence’s John Murphy said in an analysis in July. Pfizer has said its price for the shot is $295.

But the FDA’s warning may weigh on sales, along with its decision to reduce the time window for use in pregnant women to weeks 32 to 36 of gestation. The clinical trial was for 24 to 36 weeks of the pregnancy.

“That will definitely impact adoption,” David Risinger, of the investment bank Leerink Partners, said in an interview before Friday’s vote. “That also adds some complexity for providers in their discussions with pregnant women.” He sees sales of Sanofi and Astra’s preventive drug at around $2.3 billion by 2030, compared with $560 million for Pfizer’s vaccine.

Most infants will likely only need the maternal RSV vaccine or infant immunization, not both, the CDC said. However, if a baby is born less than two weeks after maternal immunization, then a doctor may recommend the infant immunization, the CDC said.

Members of the CDC advisory group raised the issue of whether insurance coverage for only one form of protection — either the maternal vaccine and the antibody — might pose problems for parents. There was also concern parents would forget whether they’d received the shot, making difficult to verify whether their children were protected.

(Updates with CDC director’s signoff starting in first paragraph.)

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