[The significance of respiratory syncytial virus as pathogen in respiratory tract infections in infants (author's transl)].

Ten out of twenty babies aged up to twelve months and admitted during the months February and March 1978 were shown to be infected with Respiratory Syncytial Virus. During the first 6 months of life the disease usually presents as bronchiolitis. Serologically only neutralising antibodies were demonstrable in this age group. IgA was usually raised in babies with bronchopneumonia. An allergic reaction between virus antigen and maternal antibodies is considered to occur, assuming an activation of the infant's own secretory immunoglobulin.