According to research at IDWeek 2017, secondhand smoke increases the risk of inflammation for infants with respiratory syncytial virus bronchiolitis. Exposure to secondhand smoke also suppresses T and B cell responses.

Infants with severe RSV disease (severity score = >10) had a median nicotine concentration of 5.3 ng/mg, whereas those with mild disease (severity score = <5) had a median score of 2.1 ng/mg (P = .49). Significantly greater overexpression of genes associated with inflammation, apoptosis and cell death were observed in the blood transcriptional profiles of infants with RSV who were exposed to secondhand smoke. The researchers also noted a greater suppression of T cell- and B cell- related genes in this cohort.

“Parents do not realize that babies breathe faster than adults and therefore their ability to inhale — in this case, tobacco smoke — increases exponentially,” M. Asuncion Mejias, MD, PhD, from the Center for Vaccines and Immunity at The Research Institute at Nationwide Children’s Hospital, told Infectious Diseases in Children.