A federal health committee reviewing data from the previous respiratory syncytial virus (RSV) season called the effectiveness of nirsevimab in infants “outstanding” as it recommended continued immunization in the 2024-’25 RSV season.
The Centers for Disease Control and Prevention’s (CDC’s) Advisory Committee on Immunization Practices (ACIP) reviewed the data Friday. ACIP officials said ample amount of the immunization should be available this fall, after shortages were experienced last RSV season.
RSV product data
Committee members reviewed safety and effectiveness data gathered during the previous RSV season on nirsevimab (Beyfortus, Sanofi and AstraZeneca) and maternal RSV vaccine (Abrysvo, Pfizer), both of which aim to protect infants and young children from RSV.
The maternal RSV vaccine is recommended for pregnant people at 32-36 weeks’ gestation. It is administered during September-January in most of the U.S.
Nirsevimab, a monoclonal antibody, is recommended for infants under 8 months during their first RSV season and high-risk toddlers 8-19 months.
RSV causes about 50,000 to 80,000 hospitalizations and 100 to 300 deaths per year in children under 5 years, according to the CDC.
Data collected from Oct. 3, 2023, to March 31, 2024, show nirsevimab was effective against RSV-associated emergency department (ED) encounters and hospitalization among infants in their first RSV season. Data from the VISION Multi-Site Network of Electronic Health Records of 127 emergency departments and 107 hospitals show nirsevimab was 77% effective at preventing RSV-associated ED encounters and 98% effective at preventing RSV-associated hospitalization, numbers that drew applause during the ACIP meeting.
“Even with caution, these results are outstanding,” said ACIP Chair Helen Keipp Talbot, M.D., professor of medicine at Vanderbilt University in Tennessee. “It’s phenomenal. We’ve heard several comments about payer issues, and I’m from a southern state and we start early with RSV. I would just find it absolutely negligent, based on this data, not to go ahead and pay for this. This is unbelievable and is life-saving and life-changing, and it’s just fantastic.”
In clinical trials among pregnant people at 24-36 weeks’ gestation, more preterm births were noted among Pfizer RSV vaccine recipients compared to placebo (5.7% vs. 4.7%), though the differences were not statistically significant.
From October 2023 to March 2024, about 17.8% of pregnant people ages 18-49 years were vaccinated with Abrysvo, according to the Vaccine Safety Datalink. In that timeframe, 43% of babies born received nirsevimab, meaning 51.2% of children born in that timeframe were protected from RSV either by maternal vaccination or nirsevimab.
Officials said shortages of nirsevimab experienced last year are not expected this coming season.
“CDC and the Food and Drug Administration (FDA) have been meeting regularly with the manufacturer since October to review the challenges from the last season and discuss planning for next season,” said Shannon Stokley, Dr.P.H., deputy director for science implementation, Immunization Services Division of the National Centers for Immunization and Respiratory Disease. “The manufacturer supply plan is to have limited availability starting in September, but then ramping up and having broad availability of the product by Oct. 1.”
People who have received a maternal RSV vaccine during pregnancy should not receive additional doses during future pregnancies. Rather, that infant should receive nirsevimab.
There also is a push to enroll more birthing hospitals in the Vaccines for Children program to ensure broad access to nirsevimab.
Studies will continue throughout the 2024-’25 RSV season, and additional recommendations may be made based on the data.
Meningococcal vaccine schedule
ACIP members reviewed clinical trial data on GlaxoSmithKline’s (GSK) 5-in-1 meningococcal ABCWY (MenABCWY) vaccine, which seeks to simplify immunization protection offered by meningococcal vaccines in fewer shots. The discussion was held in conjunction with previously discussed alterations to the adolescent meningococcal vaccine schedule and members were asked to consider adding language to include high-risk groups.
Committee members initially discussed the changes in February, and a final vote on an updated schedule could take place early next year.
The GSK pentavalent vaccine is under review by the FDA and is expected to become available in 2025. The vaccine is proposed for individuals ages 10-25 years and is administered in two doses at least six months apart.
The current schedule recommends children receive their first dose of meningococcal conjugate (MenACWY) vaccine at ages 11-12 years and a second dose at 16 years.
Those who are not at increased risk of meningococcal disease could receive two doses of serogroup B meningococcal disease (MenB) vaccine between 16 and 23 years (preferably at 16-18 years old), following shared decision-making between a health care provider and patient or the patient’s parent/guardian.
Proposals include removing one MenACWY dose and/or offering MenB doses based on risk instead of routine vaccination schedule. Members were asked to consider the new pentavalent vaccine’s potential availability as immunization schedule revisions are considered over the coming months.
While primary data showed a “favorable safety profile” to the pentavalent vaccine, ACIP members pointed out titers waned substantially for serogroup A and for three B strains after 24 months. Though a robust response was shown when a booster dose was administered after the primary series, work group members expressed concerns about the drop in protection at two years for serogroup B strains
ACIP members also were tasked with identifying risk groups for potential broader use of MenB vaccination, including adolescents in congregate living settings, such as college students, and those in congregate foster care, boarding schools, correctional facilities, etc.
A proposal for a revised vaccination schedule would allow adolescents who desire protection to receive MenB vaccine, even if they are unsure of future living plans that may inform congregate living risk.
No votes were taken Friday, and ACIP members will reconvene in October.
