Advances in respiratory syncytial virus vaccine development.

Respiratory syncytial virus (RSV) is the most important causative agent of respiratory tract infections. Young children with chronic lung or congenital heart disease are at increased risk for severe disease. Intensive research into a candidate vaccine has yielded live attenuated vaccines and subunit vaccines, which have been studied in humans. Although immunogenic, occurrence of upper respiratory tract infection symptoms with live attenuated vaccine prohibits evaluation in young infants. Subunit vaccines include purified F protein (PFP-1 and -2) and BBG2Na. PFP vaccines are effective in seropositive children, but also induce upper respiratory symptoms. BBG2Na was being investigated in phase III clinical trials, however, further development has now been discontinued. This review discusses recent advances in RSV vaccine development.