Nasal spray flu vaccine does not exacerbate asthma in children older than 4 years

The quadrivalent live attenuated influenza vaccine — also known as the nasal spray vaccine — does not exacerbate asthma in children aged older than 4 years, according to data from a randomized controlled trial published in Pediatrics.

The quadrivalent live attenuated influenza vaccine (LAIV4) is preferred by some parents and children as a relatively painless alternative to the more commonly administered inactivated influenza vaccines, which are delivered via intramuscular injection.

The authors of the new study noted that the CDC’s Advisory Committee on Immunization Practices has recommended against administering the LAIV4 to children aged 2 to 4 years with asthma or a wheezing episode in the past year, but said “it remains unclear whether LAIV may be appropriate for children 5 years of age and older with asthma, for whom there is currently a precaution to receiving LAIV.”

“Early studies of LAIV suggested a higher incidence of wheezing in LAIV recipients compared with IIV recipients,” they wrote.

The researchers enrolled 151 children with persistent asthma aged between 5 and 17 years and studied them over the course of two influenza seasons. They randomly assigned the participants to receive either LAIV4 or a quadrivalent IIV (IIV4), and monitored them for any asthma symptoms for the next 42 days.

Overall, 18 of the 142 (13%) participants included in the per-protocol analysis experienced an asthma exacerbation — eight in the LAIV4 group and 10 in the IIV4 group, a risk difference of –0.0390 (90% CI, –0.1453-0.0674), meeting the bounds for noninferiority.

“There were no significant differences in the frequency of asthma symptoms, change in [peak expiratory flow rate], or childhood asthma control test/asthma control test scores in the 14 days postvaccination between LAIV4 and IIV4 recipients,” the researchers wrote.

“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, in situations of public/school mass vaccination clinics using LAIV, or for children with significant needle aversions,” they wrote.