The Impact of Rhinovirus, Syncytial Respiratory Virus and Helminth Infection on the Risk of New-Onset Asthma and Other Allergic Conditions—A Systematic Review for the EAACI Guidelines on Environmental Science for Allergic Diseases and Asthma

This systematic review evaluated the association between lower respiratory tract infections (LRTI) in infancy with respiratory syncytial virus (RSV), rhinovirus (RV) or infestation with helminths and the risk of developing asthma and allergic diseases. The risk of bias was assessed with ROBINS-E, and the certainty of evidence (CoE) with GRADE. Meta-analysis applied a random-effects model. RSV LRTI is likely associated with an increased risk of developing asthma by age 7 (OR 3.02, 95% CI 2.23–4.09; I² = 98%; moderate CoE). The impact on wheezing, atopic dermatitis (AD), and allergic rhinitis is uncertain. RV LRTI may be associated with increased risk of developing asthma (OR 8.40, 95% CI 2.56–27.55; I² = 43%; low CoE). The impact on wheezing and AD is uncertain. Trichuris trichiura infestation might be associated with reduced risk of new-onset wheezing (OR 0.57, 95% CI 0.35–0.94; very low CoE) or AD (HR: 0.35, 95% CI 0.18–0.67; very low CoE). The association between Ascaris lumbricoides and hookworm infestation and the risk of developing asthma or AD is uncertain. Infestation with any helminths might be associated with reduced risk of new-onset asthma by age 5 (OR: 0.60, 95% CI 0.38–0.95; very low CoE) and wheezing (OR 0.70, 95% CI 0.51–0.95; very low CoE). More high-quality studies are needed to confirm these findings.