FDA Advises Continued Caution in Moderna’s RSV Vaccine Trials for Infants Amid Safety Concerns

The FDA advisory committee has voiced significant safety concerns regarding the trial of Moderna's mRNA-based RSV vaccines, specifically mRNA-1345 and mRNA-1365, in infants. This concern arises from an observed imbalance in severe RSV lower respiratory tract infections among vaccinated infants and a potential reduction in the efficacy of the prophylactic antibody, Beyfortus, following vaccination[1][2]. The committee discussed the need for additional studies to further explore these safety signals and emphasized the importance of monitoring immune responses without completely halting the trials[3]. The partial pause affects trials involving children under two, with an emphasis on gathering more data to fully understand these safety implications as Moderna continues facing competition from companies like GSK and Pfizer in the RSV vaccine market[2][4].