About 88% of lower respiratory events included diagnoses for asthma exacerbations. When the investigators adjusted the data for age, asthma severity, asthma control, race or ethnicity, and Medicaid coverage, they found no increase in lower respiratory events associated with the LAIV guideline. The adjusted ROR was 0.74 for lower respiratory events within 21 days of vaccination and 0.77 for lower respiratory events within 42 days of vaccination. The results were similar when Dr. Nordin and colleagues stratified the data by age group, and including additional covariates did not alter the ROR estimates. In all, 21 hospitalizations occurred within 42 days of influenza vaccination, and the LAIV guideline did not increase the risk for hospitalization.
“Findings from this study are consistent with several recent observational studies of LAIV in children and adolescents with asthma,” said Dr. Nordin and colleagues.
One limitation of the current study was that the data were restricted to the information available in electronic health care or claims records. The researchers therefore were able to observe only medically attended lower respiratory events. Furthermore, the exclusion of asthma management encounters and the classification of asthma severity were based on diagnoses, visits, and medication orders and fills. The estimates thus are prone to misclassification, which may have biased the results. Finally, information on important variables such as daycare attendance, presence of school-age siblings, and exposure to secondhand smoke was not available.
The research was funded by a grant from the National Institute of Allergy and Infectious Diseases. The authors had no relevant financial disclosures.
SOURCE: Nordin JD et al. Vaccine. 2019 Jun 10. .