Live Attenuated versus Inactivated Influenza Vaccine in Infants and Young Children

An intranasally administered influenza vaccine may be useful in efforts toward universal vaccination of children less than 5 years of age. In this trial involving 8352 young children, the attack rate for symptomatic influenza was 5% with the live attenuated vaccine, as compared with 10% with the inactivated influenza vaccine administered intramuscularly. However, with the live vaccine, as compared with the inactivated influenza vaccine, there was a higher rate of hospitalization for any cause among children younger than 12 months of age. In this trial involving 8352 young children, the attack rate for symptomatic influenza was 5% with the live attenuated vaccine, as compared with 10% with the inactivated influenza vaccine. However, with the live vaccine, there was a higher rate of hospitalization for any cause among children younger than 12 months of age. Hospitalization rates for culture-confirmed influenza among young children are similar to those among the elderly, and outpatient visits for confirmed influenza are more frequent among infants and young children than in any other age group. 1 For these reasons, U.S. advisory bodies have recently recommended the routine vaccination of all children 6 to 59 months of age with the licensed trivalent inactivated influenza vaccine. 2 The implementation of this recommendation will be challenging because of the limited supplies of inactivated vaccine during many influenza seasons, 3 – 5 the modest efficacy of inactivated vaccine in young children, 6 and the frequent need to administer the . . .