Children with asthma and recurrent wheezing who received the intranasal live attenuated influenza vaccine (LAIV) did not experience increased lower respiratory events (LREs) compared with children who received the inactivated influenza vaccine (IIV) injection, a large study has found. James D. Nordin, MD, HealthPartners Institute, Minneapolis, Minnesota, and colleagues conducted a retrospective cohort study in 4771 children aged 2 to 17 years with asthma who received one or more influenza vaccines before and after the implementation of a guideline recommending LAIV over IIV for children with asthma or recurrent wheezing. The current recommendations from the Advisory Committee on Immunization Practices of the US Centers for Disease Control and Prevention are more cautious about the use of LAIV in children with asthma or recurrent wheezing. "Currently, LAIV is not recommended for children 2-4 [years of age] with asthma," coauthor Elyse O. Kharbanda, MD, MPH, also of HealthPartners Institute, told Medscape Medical News. "For children 5 and older, asthma is a precaution for receiving LAIV. As far as we know there have not been any recent changes to these guidelines." The researchers published their findings online June 10 in Vaccine. "We believe that the findings from this study, along with those from related studies, support the safety of LAIV in children 2 [years] and older, including those with asthma or reactive airway disease," Kharbanda said. The children received their vaccinations at two medical groups within a large nonprofit integrated healthcare system between 2007 and 2016. Both medical groups followed standard guidelines recommending IIV preferentially over LAIV for children with asthma until 2010; in 2010, one group (LAIV group) began recommending the LAIV preferentially over IIV for all children and adolescents including those with asthma. The children received a total of 7851 influenza vaccinations. After adjustment for age, race/ethnicity, Medicaid insurance, and baseline asthma severity and control, LREs did not increase in the LAIV guideline group compared with the IIV group after implementation of the LAIV guideline (overall adjusted ratio of rate ratios [aROR], 0.74; 95% confidence interval [CI], 0.43 - 1.29 for LRE within 21 days of vaccination and aROR 0.77; 95% CI, 0.53 - 1.14 for LRE within 42 days of vaccination). Among the children aged 2 to 4 years the aROR was 0.92 (95% CI, 0.34 - 2.53) for LRE within 21 days of vaccination and 0.94 (95% CI, (0.49 - 1.82) for LRE within 42 days of vaccination. For those aged 5 to 17 years, the aROR was 0.58 (95% CI, 0.26 - 1.30) for LRE within 21 days of vaccination and 0.67 (95% CI, 0.37 - 1.23) for LRE within 42 days. The use of LAIV increased from 23% before the guideline to 68% after the guideline in those with asthma in the LAIV group compared with an increase from 7% to 11% in the control group after adjusting for age, asthma severity, and asthma control. Strengths of the study include the large number of children and adolescents with asthma who received influenza vaccination and the fact that the researchers used the ROR analytic approach. "Our study differs from prior observational studies of LAIV in patients with asthma because the vaccine was routinely recommended to all patients with asthma in the post-guideline period. As such, our cohort includes patients with persistent asthma and our findings are less prone to bias by indications (where only mild asthmatics would receive LAIV)," Kharbanda explained. Study limitations include the fact that the researchers were limited to data that were available in the electronic health record or claims records, and the researchers were not able to analyze data on LREs that may have been cared for at home. The researchers also did not address upper respiratory events that can occur after influenza vaccination, including nasal drainage and sinusitis. "These additional data strengthen existing data suggesting that the LAIV vaccine is safe for children with asthma older than 2 years of age, and that guidelines for influenza vaccination in children with asthma over age 2 should allow use of either vaccine and be based on vaccine effectiveness," the authors conclude. Source
