ABSTRACT
OBJECTIVE: Evaluate whether a guideline recommending Live Attenuated Influenza Vaccine (LAIV) for children 2â¯years and older with asthma increased risks for lower respiratory events (LREs), within 21 or 42â¯days of vaccination, as compared to standard guidelines to administer Inactivated Influenza Vaccine (IIV) in children with asthma. METHODS: This was a pre/post guideline retrospective cohort study of children ages 2-17â¯years with asthma and receiving one or more influenza vaccines in two large medical groups from 2007 to 2016. Both groups recommended IIV in the pre-period; in 2010, one group implemented a guideline recommending LAIV for all children, including those with asthma. Main outcomes were medically attended LREs within 21 and 42â¯days after influenza immunization. Analysis used a generalized estimating equation regression to estimate the ratio of rate ratios (RORs) comparing pre/post events between LAIV guideline and control group. RESULTS: The cohort included 7851 influenza vaccinations in 4771 children with asthma. Among patients in the LAIV guideline group, the proportion receiving LAIV increased from 23% to 68% post-guideline implementation, versus an increase from 7 to 11% in the control group. Age and baseline asthma severity adjusted ROR showed no increase in LREs, primarily asthma exacerbations, following implementation of the LAIV guideline: overall aROR (95% Confidence Interval): 0.74 (0.43-1.29) for LRE within 21â¯days of vaccination, 0.77 (0.53-1.14) for LRE within 42â¯days of vaccination. For the subset of children ages 2-4â¯years aROR: 0.92 (0.34-2.53) for LRE within 21â¯days of vaccination and 0.94 (0.49-1.82) for LRE within 42â¯days of vaccination; for children 5-18â¯years aROR (95% CI): 0.58 (0.26-1.30) for LRE within 21â¯days of vaccination and 0.67 (0.37-1.23) for LRE within 42â¯days. CONCLUSION: In a large cohort of children with asthma, a guideline recommending LAIV rather than IIV did not increase LREs following vaccination.
