Pfizer’s respiratory syncytial virus (RSV) vaccine Abrysvo (RSVpreF) recently received FDA approval for the prevention of lower respiratory tract disease (LRTD) and severe LRTD caused by RSV in infants from birth up to six months of age by active immunization of pregnant individuals at 32-36 weeks gestation.* A few weeks ago, AstraZeneca and Sanofi’s monoclonal antibody (mAb) Beyfortus (nirsevimab) also received FDA approval for the prevention of RSV LRTD in babies and toddlers. These therapies have the potential to considerably reduce the burden of RSV infection among young children ahead of the 2023/2024 season, says GlobalData, a leading data and analytics company.

The FDA nod for Abrysvo marks the first regulatory approval for a maternal RSV vaccine anywhere in the world. RSV is a viral respiratory illness that is extremely common in young children. GlobalData epidemiologists project seroprevalence among 2-year-old children in the US to be around 94% in 2023, amounting to an affected population of 3.9 million and indicating that the vast majority of children are infected with the virus in the first two years of life.

Fiona Chisholm, Associate Director of Infectious Diseases at GlobalData, comments: “RSV often causes mild, cold-like symptoms, but it can also lead to more serious LRTD, such as pneumonia and bronchiolitis, and can be life-threatening. This is particularly the case for vulnerable patient cohorts such as preterm infants and infants with congenital muscular, respiratory, or cardiovascular disease. The first six months of life represent a major susceptibility window for RSV. Children who become infected at this age have an increased likelihood of experiencing severe illness, hospitalization and death compared to older children, which underlines the importance of prophylaxis for this age cohort.”

Beyfortus is a single-dose long-acting antibody that acts by neutralizing the RSV-F protein. The Centers for Disease Control and Prevention (CDC) has recommended routine use of the mAb in all infants below 8 months of age born during or entering their first RSV season and in high-risk children aged 8-19 months of age entering their second RSV season.

Chisholm continues: “AstraZeneca’s mAb Synagis (palivizumab) has been used to prevent RSV in pediatric patients for nearly 25 years, but its use has been limited to infants at high risk of severe disease. The CDC recommendation for Beyfortus means that over one million infants will now be eligible to receive RSV prophylaxis in the first few months of life when they are most vulnerable to complications of the infection.”

Additionally, as a maternal vaccine, Abrysvo induces the production of antibodies, which are transferred transplacentally in order to provide infants with protection against RSV from birth. The CDC has not yet provided recommendations on the use of Abrysvo among pregnant individuals. However, key opinion leaders (KOLs) interviewed by GlobalData in 2021 emphasized that maternal vaccines and prophylactic mAbs could play important complementary roles in reducing the burden of RSV among the pediatric population.

Chisholm concludes: “Healthcare providers in the US now have much better resources at their disposal to protect young children against RSV, and this is likely to reduce the burden of RSV on the healthcare system for the upcoming season.”

* Previously, in May 2023, Abrysvo received FDA approval for the prevention of LRTD caused by RSV in individuals 60 years of age or older