Our observations of reduced fever at 1 month and reduced stuffy nose at 6 months associated with nonprone sleep positions are consistent with this hypothesis, as is the reported observation that adults with
upper respiratory tract infections have lower nasal bacterial counts
after lying supine for 1 hour vs lying prone for 1 hour.11 Also, infants sleeping supine swallow more frequently than infants sleeping prone in response to a pharyngeal fluid stimulus, suggesting more effective clearing of nasopharyngeal secretions in the supine position and, hence, less potential for eustachian tube obstruction and fewer ear
infections.12
The protection was strongest immediately
after birth, but was ineffective past seven months [37] Breastfeeding appears to reduce symptoms of
upper respiratory tract infections in premature infants up to seven months
after release from hospital.