Respiratory syncytial virus prevention: past and present strategies.

Respiratory syncytial virus (RSV) is a common cause of respiratory illness in young children, almost all will have been infected by the age of two years old. Very young infants, and those with underlying disease, are at risk of severe RSV disease, but even those who were previously healthy can suffer recurrent respiratory symptoms 9 to 10 years after their initial infection. The management of RSV infection is essentially supportive, thus prophylaxis offers the best hope of reducing the morbidity and mortality of RSV infection. There is no safe and effective RSV vaccine to use in those infants who are at highest risk from the infection. Immunoprophylaxis, however, has been shown to have benefits in randomised controlled trials. Standard immunoglobulin, however, is ineffective as its administration does not achieve an adequate titre of neutralising antibodies. RSV immunoglobulin (RSV-IGIV, RespiGam, Massachusetts Public Health Laboratories, Boston, MA), in contrast, contains high levels of RSV neutralising antibody and has been shown to significantly reduce hospitalisation in preterm infants with or without bronchopulmonary dysplasia (BPD). Its use is not recommended in infants with cyanotic congenital heart disease (CHD), as it was associated with an excess of adverse events. A humanised RSV monoclonal antibody (Palivizumab, MEDI-493, Synagis, MedImmune Inc, Gaithersburg, MD) also significantly reduces hospitalisation for RSV infection in high risk infants, but without serious side effects. The American Academy of Paediatrics has recommended that immunoprophylaxis should be considered for young children at high risk of severe RSV infection and that palivizumab is the preferred agent. Studies have suggested it is essential to carefully select patients for immunoprophylaxis, if its use is to be cost-effective.