Abstract
Among infants with prematurity and/or chronic lung disease for whom respiratory syncytial virus immunoprophylaxis is recommended, we examined adherence in infants enrolled during healthcare visits for acute respiratory illness in 3 U.S. counties from 2001 to 2007. Immunoprophylaxis among infants who met national criteria for prophylaxis increased from 33% to 83% over the 6-year period; 17% (11/65) of infants who received immunoprophylaxis did not meet eligibility criteria.