In an unusual move, federal health officials revised their recommendations for who should receive the vaccine against the respiratory syncytial virus.
The Centers for Disease Control and Prevention recommended last year that adults age 60 or older could receive a single lifetime dose of an R.S.V. vaccine, in consultation with their health care providers.
On Wednesday, scientific advisers to the agency reframed that guideline. Based on recent safety and effectiveness data, they unanimously recommended that all Americans age 75 and older receive one dose of an R.S.V. vaccine.