Safety of LAIV Vaccination in Asthma or Wheeze: A Systematic Review and GRADE Assessment

CONTEXT: The US Advisory Committee on Immunization Practices states a contraindication for live attenuated influenza vaccine (LAIV) use in children aged 2 to 4 years with asthma or recurrent wheeze plus a precaution, defined as defer vaccine use, in those aged >5 years with asthma. OBJECTIVE(S): We assessed the certainty of evidence on the safety of LAIV vs inactivated influenza vaccine (IIV) or no vaccine, or before vs after LAIV, in eligible individuals with asthma and/or wheeze. DATA SOURCES: Embase, MEDLINE, CCTR, and CDSR were searched for eligible studies (database inception to August 27, 2024) via Ovid/Elsevier. STUDY SELECTION: Screening (title/abstract and full text) and data extraction were performed by a single reviewer; an independent reviewer screened 10%. Risk of bias (ROB) was assessed using ROB2 and ROBINS-I. Evidence certainty was assessed using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) framework. RESULT(S): Searches yielded 24 eligible studies (28 publications); 15 comparative studies were included in the GRADE assessment. No difference in patient-reported safety outcomes was reported in 86.7% of studies comparing LAIV and IIV (all ages and disease severities; "very low" to "moderate" certainty evidence). A higher instance of rhinitis and a lower incidence of inpatient/emergency department visits and wheezing were reported after LAIV vs IIV. Evidence was mostly downgraded for ROB, imprecision, and indirectness. Similar results were observed for all comparisons. LIMITATIONS: The heterogeneity of identified outcomes precluded a meta-analysis. CONCLUSION(S): This suggests comparable safety outcomes with LAIV vs IIV in persons with asthma and/or recurrent wheeze, irrespective of disease severity. Copyright © 2025 American Academy of Pediatrics. All rights reserved.