Significance of respiratory virus isolations. A study in primary schoolchildren

Abstract

This study was undertaken in a primary school to determine how frequently viruses, Mycoplasma pneumoniae, and pathogenic bacteria could be isolated from children in whom there was no evidence of acute respiratory infection. The clinical status was firmly established before the virological and bacteriological results were recorded. Respiratory illness was found during 79 out of 224 interviews (35%). Specimens were taken at 112 of these interviews and children were re-examined 6 days later to ensure that no symptoms had developed during the intervening period. Viruses were isolated from 2 out of 65 (3%) of the investigations performed in asymptomatic children, compared with 11 out of 47 (23%) in those who had episodes of mild respiratory illnesses. Haemophilus influenzae and Streptococcus pneumoniae were more commonly isolated in the 47 children with symptoms than in those without. There was a close correlation between the virological findings of this study and those in children attending a nearby general practice, where the isolation rate in episodes of respiratory illness was 23% during the same period.