OBJECTIVE: Evaluate whether a guideline recommending Live Attenuated Influenza Vaccine (LAIV) for children 2years and older with asthma increased risks for lower respiratory events (LREs), within 21 or 42days 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 2-17years 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 42days 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 21days of vaccination, 0.77 (0.53-1.14) for LRE within 42days of vaccination. For the subset of children ages 2-4years aROR: 0.92 (0.34-2.53) for LRE within 21days of vaccination and 0.94 (0.49-1.82) for LRE within 42days of vaccination; for children 5-18years aROR (95% CI): 0.58 (0.26-1.30) for LRE within 21days of vaccination and 0.67 (0.37-1.23) for LRE within 42days. CONCLUSION: In a large cohort of children with asthma, a guideline recommending LAIV rather than IIV did not increase LREs following vaccination.