AN UPDATE ON APPROACHES TO THE DEVELOPMENT OF RESPIRATORY SYNCYTIAL VIRUS (RSV) AND PARAINFLUENZA VIRUS TYPE-3 (PIV3) VACCINES

RSV and PIV3 are responsible for about 30% of severe viral respiratory tract disease leading to hospitilization of infants and children. For this reason, there is a need to develop vaccines effective against th ese viruses. Since these viruses cause severe disease in early infancy , vaccines must be effective in the presence of maternal antibody. Cur rently, several strategies for immunization against these viruses are being explored including peptide vaccines, subunit vaccines, vectored vaccines (e.g., vaccinia-RSV or adenovirus-RSV recombinants), and live attenuated virus vaccines. The current status of these approaches is reviewed. In addition, the immunologic basis for the disease potentiat ion seen in vaccinees immunized with formalin-inactivated RSV during s ubsequent RSV infection is reviewed. The efficacy of immunization in t he presence of maternal antibody is discussed. Much progress for a RSV and PIV3 vaccine has been made and successful immunization against ea ch of these pathogens should be achieved within this decade.