DEVELOPMENT OF PARAINFLUENZA VIRUS AND RESPIRATORY SYNCYTIAL VIRUS SUBUNIT VACCINES

Human respiratory syncytial virus (RSV) (McIntosh and Chanock, 1990) and parainfluenza virus (PIV) types 1,2,3 (Chanock and Mclntosh, 1990) have been identified as the major viral pathogens responsible for severe respiratory tract infections in infants and young children. In the United States alone, approximately 4,500 infants and young children are expected to die each year as a result of severe respiratory tract infections caused by RSV (Katz, 1985). The global annual infection and mortality figures for RSV are estimated to be 65 million and 160,000, respectively (Robbins and Freeman, 1988). Recent epidemiological data has indicated that RSV also causes significant morbidity and mortality in the elderly (Falsey et al, 1995), the immunocompromised (Englund et al., 1988) as well as in hospitalized adults with lower respiratory tract infections (Dowell et al., 1996). With respect to the parainfluenza viruses, PIV-3 is second only to RSV as the causative agent of bronchiolitis and pneumonia in infants less than 6 months of age. Annually, approximately 1,000 infants may die in the United States from severe respiratory tract infections caused by PIV-3. Furthermore, it is estimated that 600,000 children under the age of 6 develop laryngotracheobronchitis (croup) each year as a result of infection with PIV-1 and 2 (Katz, 1985). It has also been recently reported that the parainfluenza viruses can cause life threatening pneumonia in adult bone marrow transplant recipients (Lewis et al., 1996).