Safety of Live Attenuated Influenza Vaccine in Children With Asthma

Abstract

Current recommendations caution against the use of live attenuated influenza vaccine (LAIV4) in children ≥5 years of age with asthma. The primary objective was to compare the proportion of participants with asthma exacerbations postimmunization among children with persistent asthma who received LAIV4 versus quadrivalent inactivated influenza vaccine (IIV4).Participants were enrolled over 2 influenza seasons from October 2018 to December 2019 at 3 trial sites (Vanderbilt University Medical Center, Nashville, TN, Duke University Health System, Durham, NC, and Cincinnati Children’s Hospital Medical Center, Cincinnati, OH). Children 5 to 17 years of age with a current diagnosis of persistent asthma (on a daily controller) were considered eligible for the study.Participants were randomly assigned 1:1 to receive IIV4 or LAIV4 and monitored for asthma symptoms, exacerbations, changes in peak expiratory flow rate (PEFR), and changes in the asthma control test for 42 days after vaccination.142 participants were included in the per-protocol analysis. Within 42 days postvaccination, 18 of 142 (13%) experienced an asthma exacerbation: 8 of 74 (11%) in the LAIV4 group versus 10 of 68 (15%) in the IIV4 group (LAIV4-IIV4 = −0.0390 [90% confidence interval −0.1453 to 0.0674]), meeting the bounds for noninferiority. When adjusted for asthma severity, LAIV4 remained noninferior to IIV4. Vaccine reactogenicity was similar between groups.LAIV4 was not associated with increased frequency of asthma exacerbations, an increase in asthma-related symptoms, or a decrease in PEFR compared with IIV4 among children aged 5 to 17 years with asthma.Current Centers for Disease Control and Prevention guidelines advise taking precautions when using the nasal spray flu vaccine in people with asthma 5 years and older. However, this randomized, controlled trial in 5 to 17-year-old children with persistent asthma showed that LAIV4 was no more likely to be associated with asthma exacerbations than IIV4. Historical context also is informative in relatively low enrollment, despite recruitment over 2 flu seasons. There was reduced provider and parental confidence in LAIV4 because of the Centers for Disease Control and Prevention recommendations against use of the nasal spray vaccine for the 2016 to 2017 and 2017 to 2018 seasons because of studies showing that the nasal spray vaccine was less effective than inactivated flu vaccines against the 2009 pandemic H1N1 viruses. LAIV was recommended again in the 2018 to 2019 influenza season, but there have been no effectiveness estimates in the United States. Data from other countries have demonstrated protection from LAIV to be similar to that of the inactivated flu vaccine in children. Nevertheless, these data support reexamining precautions to using LAIV4 in children with asthma, which could be particularly important during influenza pandemics, at times when IIV4 supplies are limited or for children with significant needle aversions.URL: www.pediatrics.org/cgi/doi/10.1542/peds.10.1542/peds.2021-055432