Science Recently approved adult vaccines against respiratory syncytial virus (RSV) are already saving lives. But prospects have dimmed for some infant vaccines against the virus, which each year kills up to 100,000 children under age 5 around the world and is the leading cause of infant hospitalizations in the United States. In recent clinical trials, two experimental RSV vaccines for babies may not only have failed to protect them, but actually made some of them sicker when they got RSV or another respiratory virus. The findings, publicly discussed in detail for the first time yesterday, have profoundly unsettled many RSV scientists, who recall similar problems with a vaccine trial decades ago.
Scientists aren’t certain Moderna’s data signal a real problem, but the company has already stopped studies and abandoned development of the vaccines. The U.S. Food and Drug Administration (FDA), in turn, this week halted some trials of other experimental RSV vaccines for children. And scientists fear this development will be exploited by some to wrongly promote antivaccine agendas.