Background: Acute bronchiolitis caused by respiratory syncytial virus (RSV) has been associated with greater risk of recurrent wheezing and asthma. However, it is unclear whether this association is causal. RSV-specific monoclonal antibodies have been shown to reduce RSV-related hospitalisations in high-risk infants, but the longer-term follow-up has given conflicting evidence for prevention of recurrent wheeze or asthma.
Objective: We performed a systematic review and meta-analysis to determine whether monoclonal antibody prophylaxis against RSV bronchiolitis reduces the risk of subsequent recurrent wheeze or asthma. If so, this may support the hypothesis of causality.
Methods: Studies were identified via an online database search using Embase, MEDLINE, PubMed, Web of Science and the Cochrane Library. Manufacturers of monoclonal antibodies were contacted directly for unpublished data. The intervention of interest was RSV monoclonal antibody prophylaxis, and the primary outcome measure was recurrent wheeze and/or asthma. Studies were screened according to inclusion/exclusion criteria. Included studies were evaluated for quality and assessed for bias independently by 3 reviewers using the 'Grading of Recommendations Assessment, Development and Evaluation' (GRADE) approach. Results were extracted into 2 × 2 outcome tables and a meta-analysis carried out producing forest plots based on relative risk. Heterogeneity was assessed using the I2 statistic.
Results: The search identified 141 articles, which, after screening, resulted in eight studies (2 randomised controlled trials), thus including 11,195 infants in the meta-analysis. The overall result demonstrated a non-statistically significant reduction in relative risk of developing recurrent wheeze or asthma (RR 0.60; 95% CI 0.31 to 1.16). Study quality was generally low with evidence of publication bias and statistical heterogeneity. However, sub-group analysis excluding studies deemed to be 'very low' quality showed a relative risk of 0.42 (95% CI 0.22 to 0.80, p = 0.008). A further sub-group analysis for infants aged 32 to < 36 weeks showed a statistically significant relative risk of 0.35 (95% CI 0.14 to 0.86, p = 0.02).
Discussion: We did not identify an overall statistically significant benefit. However, our two sub-group analyses did find statistically significant benefits of monoclonal antibody therapy on the risk of recurrent wheeze and asthma. The main limitation of this study is the lack of high-quality randomised controlled trials, highlighting the need for more research in this field.
Keywords: Immunoprophylaxis; Monoclonal antibody; Prophylaxis; Recurrent wheeze; Respiratory syncytial virus; asthma.