[Respiratory tract infections of viral origin in infants. Examination of 103 serum pairs in autumn and following spring].

In autumn 1973 und about four months later in spring 1974 blood samples were taken from the same 103 children aged from a few months to five years and coming from different parts of Bavaria. We examined the samples for complement-fixing antibodies against the influenza virus types A, B and C, the parainfluenza virus types 1, 2 and 3, the adenoviruses and the respiratory-syncytial virus, and for neutralising antibodies against the ECHO virus type 25. At the commencement of the investigation the most frequently detected antibodies were those against adenoviruses (66.0%), ECHO virus type 25 (22.3%), influenza virus type A (15.5%) AND THE RESPIRATORY-SYNCYTIAL VIRUS (10.7%). Over autumn and winter in the four month interval between the drawing of blood samples the most frequently observed infections were those caused by the respiratory-syncytial virus (35.9%), the adenoviruses (13.6%) and the influenza viruses A and B (6.8%). By comparing the results of two blood tests from the same individual infections could be recognised more often than would have been the case if comparing the results of two different groups of children examined in autumn and spring.