Question explored with the scientific record
How many adverse events per 100 children recieving the flu mist vaccine
The short version: the evidence you got does not contain a single study that reports the rate of adverse events per 100 children receiving flu mist. That question has not been answered by the retrieval.
The records here are mostly about efficacy in special populations (HIV-infected adults [1], school-located programs [2], egg-allergic children [5, 7]), or about manufacturing and genetic stability [3, 4, 6]. None of them give a population-level rate of adverse events per 100 doses in healthy children. The closest is a 2005 open-label safety trial in healthy children aged 18 months to 18 years [8], but it reports relative risks for asthma and counts of serious adverse events across age groups, not a simple rate per 100 children. In the youngest group (18 months to 4 years), the relative risk for asthma in year 1 was 2.85 (95% CI 1.01–8.03), meaning a nearly threefold increase, though the confidence interval barely excludes no effect. The study was funded by the manufacturer (Wyeth, then MedImmune) and was open-label, not blinded or placebo-controlled.
The two egg-allergy studies [5, 7] report that about 9% of children had mild symptoms within 24 hours, but those were small, nonrandomized cohorts (282 and 68 children respectively) in a highly selected population. No study here compared flu mist to a true unvaccinated control group and counted all adverse events. Without that design, you cannot know the background rate of the same symptoms in unvaccinated children of the same age. The evidence base for the routine safety of this product in healthy children is thinner than the marketing suggests.
My call: the evidence retrieved does not support giving a rate per 100 children. The only pediatric safety trial here shows a possible asthma signal in toddlers that was not ruled out. Confidence: low, because the most informative study design was never used.
Sources used 8
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Live versus attenuated influenza vaccine uptake and post-vaccination influenza-like illness outcomes in HIV-infected US Air Force members
In a retrospective cohort of 437 HIV-infected US Air Force members, 27.7% received LAIV despite guidelines, and LAIV was not associated with increased influenza-like illness within 30 days; IIV was associated with more ILI cases.
DOI: 10.1016/j.jcv.2017.08.009 -
Nontraditional Uses of Live Attenuated Influenza Vaccine: School-Located Influenza Vaccination
A narrative review of school-located influenza vaccination (SLIV) programs using live attenuated influenza vaccine (LAIV), summarizing evidence that LAIV-based school programs can improve vaccine uptake and reduce influenza-related illness, and outlining practical components for…
DOI: 10.1093/jpids/piaa007 -
Development of one-step real-time PCR assay for titrating trivalent live attenuated influenza vaccines
This study presents a one-step real-time PCR assay for titrating trivalent live attenuated influenza vaccines, demonstrating its efficiency and accuracy compared to traditional methods.
DOI: 10.4161/hv.34453 -
Genetic stability of live attenuated vaccines against potentially pandemic influenza viruses
Three Russian live attenuated influenza vaccine (LAIV) candidates (H2N2, H5N2, H7N3) were evaluated in healthy adults across three randomized phase I trials to assess nasal shedding, transmission risk, and genetic/phenotypic stability, finding strong stability with no evidence o…
DOI: 10.1016/j.vaccine.2015.09.050 -
Safety of live attenuated influenza vaccine in atopic children with egg allergy
This study evaluates the safety of live attenuated influenza vaccine (LAIV) in atopic children with egg allergy, finding it to be well tolerated with no systemic allergic reactions reported.
DOI: 10.1016/j.jaci.2014.12.1925 -
The mutational variety of the live-attenuated influenza vaccine proteome
Mass-spectrometry re-analysis of live-attenuated influenza vaccine particles reveals tolerance to numerous point mutations across influenza A and B proteins, with mutations often at non-critical sites, offering proteomics-informed insights for predicting antigenic drift and guid…
DOI: 10.1099/acmi.ac2021.po0409 -
Safe vaccination of patients with egg allergy by using live attenuated influenza vaccine
Intranasal live attenuated influenza vaccine appears safe for egg-allergic children, with no immediate anaphylaxis and only mild nonspecific adverse events within 24 hours.
DOI: 10.1016/j.jaip.2014.08.008 -
Live Attenuated Influenza Vaccine, Trivalent, Is Safe in Healthy Children 18 Months to 4 Years, 5 to 9 Years, and 10 to 18 Years of Age in a Community-Based, Nonrandomized, Open-Label Trial
This study reports on the safety of the live attenuated influenza vaccine (LAIV-T) in healthy children aged 18 months to 18 years, demonstrating no significant increase in asthma events or medically attended acute respiratory illness following vaccination.
DOI: 10.1542/peds.2004-2258