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

Abstract

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. 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. Embase, MEDLINE, CCTR, and CDSR were searched for eligible studies (database inception to August 27, 2024) via Ovid/Elsevier. 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. 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. The heterogeneity of identified outcomes precluded a meta-analysis. This suggests comparable safety outcomes with LAIV vs IIV in persons with asthma and/or recurrent wheeze, irrespective of disease severity.