Breastfeeding reduces the severity of respiratory syncytial virus infection among young infants: A multi-center prospective study

Background: The objective of this study was to evaluate the effects of breastfeeding on the severity of respiratory syncytial virus infection in early infancy. Methods: A rapid test for respiratory syncytial virus (RSV) was administered by 16 general pediatricians from May 2002 to April 2005 in infants undergoing medical checkups for the common cold, all of whom were 100 days old or younger and had birthweights of more than 2500 g without underlying disease. Infants were divided into three groups: the Full breastfeeding group, the Partial group, and the Token group. RSV-positive cases were followed up for 10 days after the initial diagnosis and the following three points were investigated: (i) the incidence of hospitalization; (ii) the duration of hospitalization; and (iii) the incidence of requiring oxygen therapy. Results: RSV antigen was detected in 203 of the total of 892 cases, and these were diagnosed as cases of RSV infectious disease. Although there were no significant differences in the hospitalization rate among the three groups, there were significant differences in the duration of hospitalization and the rate of requiring oxygen therapy. Multivariate logistic regression revealed that the requirement of oxygen therapy was significantly lower in the Full breastfeeding group (P = 0.032; odds ratio, 0.256; 95% confidence interval, 0.074-0.892). Conclusions: Breastfeeding reduces the severity of respiratory syncytial virus infection in early infancy.