With two respiratory syncytial virus (RSV) vaccines approved by the U.S. FDA in 2023 and a third nearing its May PDUFA date, decades of research has finally provided infants and older adults protection from the disruptive and sometimes deadly virus. But what about people in the middle, particularly those with certain chronic medical conditions? New York-based Pfizer Inc. rolled out phase III data April 9 showing that its approved RSV vaccine, Abrysvo (RSVpreF), met primary endpoints in adults ages 18 to 59 who were at high risk of RSV.