Immunization, Vaccines and Biologicals

Parainfluenza 3

Parainfluenza viruses cause a spectrum of respiratory illnesses, from URIs, 30–50% of which are complicated by otitis media, to LRIs, about 0.3% of which require hospitalization. Most children are infected by parainfluenza virus type 3 (PIV-3) by the age of two years and by parainfluenza virus types 1 and 2 (PIV-1 and -2) by the age of five years. PIV-3 infections are second only to RSV infections as a viral cause of serious ARI in young children. Pneumonia and bronchiolitis from PIV-3 infection occur primarily in the first six months of life, as is the case for RSV infection. Croup is the signature clinical manifestation of infection with parainfluenza viruses, especially PIV-1, and is the chief cause of hospitalization from parainfluenza infections in children two to six years of age. However, this syndrome is relatively less frequent in developing countries. The proportions of hospitalizations associated with PIV infection vary widely in hospital-based studies. Consequently, the annual estimated rates of hospitalization fall within a broad range: PIV-1 is estimated to account for 5,800 to 28,900 annual hospitalizations in the USA, PIV-2 for 1,800 to 15,600 hospitalizations, and PIV-3 for 8,700 to 52 000 hospitalizations. Along with RSV, parainfluenza viruses are also leading causes of hospitalization in adults with community-acquired respiratory disease. More

Last updated: 25 January 2008