RSV-preventing injection in shortage as respiratory virus season begins

Sick baby with RSV

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Respiratory virus season is only starting, and demand has already outstripped supply for the newly approved and potentially lifesaving monoclonal antibody injection for preventing respiratory syncytial virus (RSV) in children.

David Margraf, PharmD, PhD, pharmaceutical research scientist at the Resilient Drug Supply Project (RDSP), said the nirsevimab-alip (Beyfortus) shortage is reminiscent of the COVID-19 vaccine rollout. RDSP is part of the University of Minnesota's Center for Infectious Disease Research and Policy (CIDRAP), publisher of CIDRAP News.

"Wealthier nations secured most early vaccine supplies, which led to delayed vaccine rollouts in many low- and middle-income countries," he said. "Even in the United States, wealthier communities had better access to vaccines, and rural areas also faced challenges due to distance and scarce resources." 

The US Food and Drug Administration (FDA) approved the long-acting drug in July, and in August the Centers for Disease Control and Prevention (CDC) recommended the prescription drug to protect all infants up to 8 months old entering their first RSV season and for high-risk children up to 24 months in their second season. RSV is the No. 1 cause of hospitalization among US infants.

On September 5, the CDC warned that RSV activity was picking up in the southeastern United States, often a bellwether for the rest of the country.

Manufacturer didn't accurately estimate demand

"Despite an aggressive supply plan built to outperform past pediatric immunization launches, demand for this product, especially for the 100 mg doses used primarily for babies born before the RSV season, has been higher than anticipated," Beyfortus co-developer Sanofi said in an October 26 statement.

Margraf said that while the FDA evaluates the manufacturing processes and facilities, the capacity of the manufacturer to meet demand is not a major consideration in the approval process. "However, the FDA does work with pharmaceutical companies post-approval to address issues related to shortages, especially with critical drugs," he said. "It may be time for the FDA to assess manufacturing capacity in the drug approval process."

Sanofi said it was working with the CDC and to ensure equitable distribution of available doses of the drug to Medicaid-eligible, uninsured, or American Indian/Alaska Native children through the Vaccines for Children (VFC) program. The company said it, along with co-developer and manufacturing partner AstraZeneca, would take a similar approach to distribution of the $495-a-dose drug on the private market.

I would've predicted pretty high demand. I think probably too much was made of vaccine hesitancy and vaccine refusal ... with people refusing COVID vaccines.

Sean O'Leary, MD

The American Academy of Pediatrics (AAP) had over the summer urged lawmakers to provide funding for broad and equitable distribution of the injection. In a Lancet Respiratory Medicine news article published yesterday, Sean O'Leary, MD, chair of the AAP's Committee on Infectious Diseases, said Sanofi didn't ask the committee for a demand estimate.

"I would've predicted pretty high demand. I think probably too much was made of vaccine hesitancy and vaccine refusal ... with people refusing COVID vaccines," he said.

Beyfortus, which is given once before or during RSV season, is the second monoclonal antibody developed to prevent the lung disease in young children. The first drug, Arexis's palivizumab (Synagis), is recommended by the American Academy of Pediatrics only for certain high-risk infants and young children and is given monthly during RSV season, according to the CDC.

Prioritizing drug for most vulnerable

On October 23, the CDC issued a Health Alert Network (HAN) advisory with recommendations for clinicians prioritizing 100-milligram (mg) doses for infants younger than 6 months and those with underlying medical conditions that predispose them to severe RSV.

A recent study, however, suggests that previously healthy infants are also at high risk for severe RSV. The JAMA Network Open study found that over 81% of infants admitted to an intensive care unit for RSV during the 2022 seasonal peak had no underlying conditions and were born full-term.

"Recommendations for using 50 mg doses remain unchanged at this time," the CDC added. "Avoid using two 50 mg doses for infants weighing ≥5 kilograms (≥11 pounds) to preserve supply of 50 mg doses for infants weighing <5 kilograms (<11 pounds)."

The CDC also recommended suspending the use of Beyfortus in children aged 8 to 19 months who are eligible for palivizumab and offering pregnant women "passive vaccination" with Pfizer's newly approved RSV vaccine RSVpreF (Abrysvo), to help protect infants up to 6 months old, as an alternative. Given at 32 to 36 weeks' gestation, Abrysvo works by triggering antibody development in the mother that passes to the fetus via the placenta.

"Nirsevimab should continue to be offered to American Indian and Alaska Native children aged 8–19 months who are not palivizumab-eligible and who live in remote regions, where transporting children with severe RSV for escalation of medical care is more challenging or in communities with known high rates of RSV among older infants and toddlers," the CDC said.

Margraf said that parents looking for Beyfortus should consult their child's pediatrician to ask about the drug's suitability and availability. "It's also a good idea to see if you are eligible for the VFC program or patient assistance programs offered by the manufacturer," he said. "Also, you should contact your health insurance company to see if nirsevimab is covered and if there are any out-of-pocket costs."

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