In The News: RSV Vaccine Research in Infants May Proceed With Caution

Medpage Today reports the Vaccines and Related Biological Products Advisory Committee (VRBPAC) of the US Food and Drug Administration (FDA) has determined research and development of an RSV vaccine for infants should continue with awareness of documented safety concerns. The committee had met in early December to discuss findings related to Moderna’s mRNA-1365 candidate for infant immunization against RSV. Ongoing studies and success in an RSV vaccine in adults was assessed as supportive of vaccine studies in younger children, in addition to the monoclonal nirsevimab.

Moderna halted studies in July of this past year relating to fears of severe side effects. Infants aged five to eight months in the study who received the vaccine saw 12.5% clinically significant/severe RSV compared to just 5% of those infants that had received the placebo. Five cases of severe had been reported compared to one for placebo.

Currently, Moderna does not plan to continue an RSV vaccine program in this age group. However, the leader of the company’s pediatric and maternal vaccines area said it will collect more data to better understand the clinical and immunological outcomes. Also during the presentation, it was noted that an imbalance in T-cell priming may be a factor in vaccine-enhanced disease that was observed live RSV vaccine administered subcutaneously or intranasally.

The committee did not take any votes. It did agree that more research should be conducted, assessing more data into the vaccine and nirsevimab interaction would be needed to draw significant conclusions. It was noted that the Data and Safety Monitoring Board was diligent in its review and the study was stopped according to protocol. It was recommended that, with more data pointing toward vaccine approval, a public education campaign explaining RSV and the need for the vaccine should be launched.

PIDS member David Cennimo commented on the study, “The cases were higher in the vaccinated groups compared to placebo, but these are small numbers. RSV infection is more severe at younger ages, so we could expect more hospitalizations when the study moved to a younger cohort, but not necessarily the discrepancy between vaccine and placebo. It is important to note that the hospitalized children were young and RSV-naïve. Looking at the older children’s data, those who were RSV-naïve also had more symptomatic infection, although not requiring hospitalization. In my mind, if the vaccine is to be most effective, it should be given ASAP after birth. The research to show safety and efficacy to that young age will be needed.”