Pfizer RSV vaccine wins CDC recommendation for seasonal use only

Pfizer’s new shot to protect infants against respiratory syncytial virus by vaccinating their mothers late in pregnancy won a limited recommendation Friday from an expert panel that advises the Centers for Disease Control and Prevention, clearing the way for a second product to protect babies against RSV to soon hit the market.

The recommendation was accepted by CDC Director Mandy Cohen shortly after the conclusion of the panel’s meeting.

“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, using either a vaccine given during pregnancy, or an RSV immunization given to your baby after birth.”

The vote, which passed the Advisory Committee on Immunization Practices by an 11-to-1 margin, was an attempt to make the choice of preventive measures less complicated for parents-to-be and the obstetricians and pediatricians who will care for each mother-baby pair. The goal is to ensure babies are protected with one or the other anti-RSV product, but ideally not both together.

Using both in a mother-baby pair would offer little or no added benefit for most babies, and would come at a high cost, with Pfizer set to charge $295 for its vaccine and the other product, Sanofi’s monoclonal antibody, priced at $495. Insurance companies are unlikely to pay for both, unless there is a medical reason for giving a child born to a vaccinated mother the monoclonal antibody.

Pfizer publicly welcomed the development.

“Today’s ACIP recommendation for maternal immunization with Abrysvo 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, chief medical affairs officer for vaccines/antivirals and evidence generation.

But the recommendation was not a clear victory for Pfizer, effectively limiting the time of the year in which use of the vaccine will be recommended.

The ACIP recommended “seasonal administration” of the company’s vaccine, meaning that its use should focus on pregnant people who would reach 32 to 36 weeks of gestation — the point when the vaccine can be given — during the period of September to January to protect babies born between October and March, when the risk of RSV infection is traditionally highest. The Pfizer vaccine would not be recommended for use in most of the continental U.S. from February to August.

In those months, Sanofi’s monoclonal antibody, Beyfortus, should be used to protect babies as they approach their first RSV season. Maternal antibodies would most likely have waned in those babies by the start of the RSV season if their mother had been vaccinated during pregnancy.

In some parts of the country — Alaska, parts of Florida, Hawaii, Puerto Rico, the U.S. Virgin Islands, and Guam — RSV can circulate year round. The seasonal rule for use of the vaccine would not apply in these areas.

Until this year, there have been no tools with which to prevent RSV, which causes enormous numbers of illnesses in young babies every year. Though the death toll in this country is not high, between 1.5 million children are taken for medical care for RSV every year, nearly half a million end up in an emergency room, and between 58,000 and 80,000 are hospitalized for these infections.

RSV transmission typically peaks some time between November and late March, but since the start of the Covid-19 pandemic, the season has been somewhat erratic. Last year the RSV season began in the early autumn and peaked just after Thanksgiving.

Though the ACIP vote limits the time during which the vaccine should be used, it is not meant to indicate a preference for the vaccine over the monoclonal antibody during the time when the vaccine would be effective, CDC vaccine expert Jefferson Jones explained to the committee. Even in the September-to-January window, pregnant people will have the option of deciding whether they want to take the shot, or would prefer to wait to have their baby receive the monoclonal antibody, he said.

Discussions between parents-to-be and obstetricians will be critical, and there were concerns raised about whether this specialty has the time or the in-depth knowledge to help pregnant people make this choice.

“There needs to be massive education,” warned Helen “Keipp” Talbot, an infectious diseases expert from Vanderbilt University, who was the sole ACIP member to vote against recommending the vaccine.

Earlier in the day, Talbot questioned the value of approving the Pfizer vaccine, given the existence of the monoclonal antibody, which appears to protect for longer and, while more expensive, appears to be more cost-effective than the vaccine. “What’s the benefit of this vaccine? Why recommend it at all?” Talbot asked.

But other members of the committee warned of the risks of relying on a single product, and alluded to the possibility that supplies of Beyfortus may not be adequate to protect an entire birth cohort in the first year after the product hits the market.

Figuring out how to rationally use these two competing products — each of which appears to be highly effective, but is accompanied by implementation challenges — has taken considerable time and discussion for CDC staff and the ACIP’s maternal and pediatric RSV work group.

But if Friday’s meeting is any indication, implementation of these tools will create challenges over the next year or two.

Some members of the ACIP questioned whether the wording of the vote meant that the Pfizer vaccine should be given preferentially to near-term pregnant people during the September-to-January window, effectively ruling out a parent’s choice to opt for the monoclonal antibody. Another member asked whether pregnant people who reached the 32-to-36 week mark of their pregnancy in February through August would be denied the right to get the vaccine.

Several members of the committee expressed deep disappointment about the cost of the vaccine, which the company had previously indicated might be sold for $200 a dose. “$295 is a hard number for me to swallow,” said Katherine Poehling, professor of pediatrics at Wake Forest School of Medicine, who nonetheless voted to recommend the vaccine.

Pablo Sanchez, a professor of pediatrics at Ohio State University, pressed Pfizer to disclose how much the company will charge for the maternal vaccine in Europe. Donna Altenpohl, vice president of market access strategy, sidestepped the question, saying pricing elsewhere has not been finalized.