Will a Quadrivalent Vaccine Solve the Problem of Influenza B Mismatches?

Influenza is a major cause of respiratory disease leading to hospitalization in infants and young children. Since the Second World War, influenza has been prevented through annual administration of inactivated vaccines. In infants and young children, however, trivalent inactivated vaccines (TIVs) have been shown to be poorly immunogenic and less effective. Recent efforts to improve immunogenicity for these age groups include the development of live-attenuated vaccines and the modification of TIVs through addition of adjuvants and increasing amounts of antigen. Also, various routes of administration have been tested.