Respiratory syncytial virus: its transmission in the hospital environment.

Respiratory syncytial virus (RSV) over the past two decades has been recognized as the most important cause of lower respiratory tract disease in infants and young children. Recently, it has also been identified as a major nosocomial hazard on pediatric wards. The potential for RSV to spread on such wards is underlined by several singular characteristics of RSV. It arrives in yearly epidemics and is highly contagious in all age groups. Immunity is of short duration, allowing repeated infections to occur. Thus, during an epidemic 20--40 percent of infants admitted for other conditions may acquire nosocomial RSV infection, as well as 50 percent of the ward personnel. The usual infection control procedures for respiratory illnesses have had limited success in controlling the spread of RSV. This may be due in part to the modes of transmission of RSV. Inoculation occurs mainly through the eye and nose, rather than the mouth. This may be via large-particle aerosols or droplets, requiring close contact. The virus, however, does not seem capable of traversing distances by small-particle aerosols. Nevertheless, it is able to remain infectious on various environmental surfaces, suggesting fomites as a source of spread. Indeed, inoculation after touching such contaminated surfaces can occur, and may be a major second means of spread, in hospitals as well as in families.