Infants who experience a severe case of respiratory syncytial virus bronchiolitis may be more likely to develop asthma as children, according to recent study results.
Researchers evaluated 206 children aged 12 months or younger who experienced a severe respiratory syncytial virus (RSV) bronchiolitis episode, and they performed follow-up every 3 months for up to 6 years. Upon enrollment, dust samples were collected at 174 participants’ homes within the first year, and 150 participants received allergy skin tests at 3 years old. A subgroup of 81 children also underwent analysis of the CCL5 (RANTES) mRNA expression in their upper airway epithelial cells upon entry and after 1 month.
Asthma was diagnosed before age 7 in 48% of participants, including 35% who were diagnosed with active asthma. Through multivariate analysis, investigators associated the following factors with diagnosis and active asthma at age 7 years, respectively:
- Maternal asthma (OR=5.21; 95% CI, 1.7-15.9 and OR=3.49; 95% CI, 1.59-7.65)
- Substantial exposure to dog allergens (OR=3.15; 95% CI, 1.29-7.68)
- Aeroallergen sensitivity at 3 years old (OR=10.7; 95% CI, 2.08-55.1 and OR=9.0; 95% CI, 1.66-48.8)
- Recurrent wheezing during the first 3 years (OR=7.31; 95% CI, 1.24-43.3 and OR=6.12; 95% CI, 1.03-36.3)
- CCL5 expression during RSV infection (OR=3.81, 95% CI, 2.07-7.01 and OR=1.67; 95% CI, 1.19-2.36 at baseline)
Decreased risk for asthma diagnosis was associated with white race (OR=0.19; 95% CI, 0.04-0.93 for diagnosis, OR=0.15; 95% CI, 0.03-0.76 for active asthma at 3 years) and day care attendance (OR=0.18; 95% CI, 0.04-0.84 for diagnosis; OR=0.14, 95% CI, 0.03-0.70 for active asthma at 3 years).
“Our results demonstrate that children who experience severe RSV bronchiolitis in infancy are at significantly increased risk for asthma during the first 6 years of life and that symptoms generally persist as children grow toward school age,” the researchers concluded. “Physicians are encouraged to closely monitor children after severe RSV bronchiolitis, to provide additional guidance to children and families with additional risk factors … for asthma, and to test at a young age for sensitization to common allergens.”