The link between respiratory syncytial virus infection during infancy and asthma during childhood

Respiratory syncytial virus (RSV) infection is a major cause of morbidity and mortality in infants. 1 Jha A Jarvis H Fraser C Openshaw PJ Respiratory syncytial virus. in: Hui DS Rossi GA Johnston SL SARS, MERS and other viral lung infections. European Respiratory Society, Sheffield, UK2016 Crossref Scopus (19) Google Scholar A 2022 birth cohort study estimated that 14% of healthy children born at term had an RSV infection that was medically attended and 1·8% were admitted to hospital for RSV in their first year of life. 2 Wildenbeest JG Billard M-N Zuurbier RP et al. The burden of respiratory syncytial virus in healthy term-born infants in Europe: a prospective birth cohort study. Lancet Respir Med. 2023; 11: 341-353 Summary Full Text Full Text PDF PubMed Scopus (6) Google Scholar A 2015 study found approximately 10% of RSV infections were asymptomatic in children younger than 1 year, suggesting that total RSV incidence is high. 3 Munywoki PK Koech DC Agoti CN et al. Frequent asymptomatic respiratory syncytial virus infections during an epidemic in a rural Kenyan household cohort. J Infect Dis. 2015; 212: 1711-1718 Crossref PubMed Scopus (45) Google Scholar Recurrent wheeze and childhood asthma have been associated with RSV bronchiolitis. 4 Sigurs N Bjarnason R Sigurbergsson F Kjellman B Respiratory syncytial virus bronchiolitis in infancy is an important risk factor for asthma and allergy at age 7. Am J Respir Crit Care Med. 2000; 161: 1501-1507 Crossref PubMed Scopus (922) Google Scholar , 5 Brunwasser SM Snyder BM Driscoll AJ et al. Assessing the strength of evidence for a causal effect of respiratory syncytial virus lower respiratory tract infections on subsequent wheezing illness: a systematic review and meta-analysis. Lancet Respir Med. 2020; 8: 795-806 Summary Full Text Full Text PDF PubMed Scopus (36) Google Scholar Clinical trials that investigated if monoclonal antibodies against RSV decreased the risk of childhood asthma have been inconsistent so far. 6 Blanken MO Rovers MM Molenaar JM et al. Respiratory syncytial virus and recurrent wheeze in healthy preterm infants. N Engl J Med. 2013; 368: 1791-1799 Crossref PubMed Scopus (478) Google Scholar , 7 Scheltema NM Nibbelke EE Pouw J et al. Respiratory syncytial virus prevention and asthma in healthy preterm infants: a randomised controlled trial. Lancet Respir Med. 2018; 6: 257-264 Summary Full Text Full Text PDF PubMed Scopus (97) Google Scholar , 8 O'Brien KL Chandran A Weatherholtz R et al. Efficacy of motavizumab for the prevention of respiratory syncytial virus disease in healthy Native American infants: a phase 3 randomised double-blind placebo-controlled trial. Lancet Infect Dis. 2015; 15: 1398-1408 Summary Full Text Full Text PDF PubMed Scopus (127) Google Scholar It remains unclear to what extent RSV increases the risk of childhood asthma, and to what extent shared genetic predisposition and environmental risk factors cause a subset of children to be at higher risk of severe RSV and childhood asthma. Respiratory syncytial virus infection during infancy and asthma during childhood in the USA (INSPIRE): a population-based, prospective birth cohort studyAmong healthy children born at term, not being infected with RSV in the first year of life was associated with a substantially reduced risk of developing childhood asthma. Our findings show an age-dependent association between RSV infection during infancy and childhood asthma. However, to definitively establish causality, the effect of interventions that prevent, delay, or decrease the severity of the initial RSV infection on childhood asthma will need to be studied. Full-Text PDF