Robert B. Belshe and Frances K. Newman
The present invention relates to isolated, attenuated viral strains of human parainfluenza virus 2 (HPIV-2), which are useful in live vaccine preparations. These strains exhibit a temperature sensitive and cold adapted phenotype useful for stimulating a protective immune response in an inoculated mammal without producing the severe symptoms caused by the wild type virus.
The human parainfluenza viruses (HPIV), types 1, 2, and 3, are important pathogens in infants and young children. HPIV routinely causes otitis media, pharyngitis, and the common cold. These upper respiratory tract infections (URI) occur commonly and may be associated with lower respiratory infections (LRI) including croup, pneumonia, and bronchiolitis. Primary infection in young children is associated with lower respiratory disease and often leads to hospitalization. As a group, the parainfluenza viruses are the second most common cause of hospital admission for respiratory infection and are second only to respiratory syncytial virus as a significant pathogen in young children. HPIV-2 infection occurs in yearly outbreaks in the United States. This pathogen has a peak incidence in the fall to early winter with a slightly longer "season" than HPIV-1. Croup is the most frequent LRI caused by this virus, but it can also cause any of the other respiratory illnesses associated with HPIV-1. The peak incidence of HPIV-2 infections occurs in the second year of life with approximately 60% of infections taking place in children less than 5 years of age.