FDA Approves AstraZeneca No-Needle At-Home 'Live' Virus Flu Vaccine with 90% Shed Rate

FluMist manufacturer insert confirms vaccinated can infect unvaccinated.

Nov 05, 2024

In September, the U.S. Food and Drug Administration (FDA) approved AstraZeneca’s FluMist for self or caregiver administration for the 2024-2025 influenza season.

Share Jon Fleetwood

Follow Jon Fleetwood: Instagram @realjonfleetwood / Twitter @JonMFleetwood / Facebook @realjonfleetwood

AstraZeneca subsidiary MedImmune, LLC, the manufacturer of FluMist, anticipates that FluMist will be available for the 2026 influenza season as well.

FluMist, which is sprayed into the nose, is now approved for the alleged prevention of influenza disease caused by influenza virus subtypes A and B in individuals 2 through 49 years of age.

Screenshot from FDA.gov taken November 5, 2024 showing FluMist vaccine package insert.

Each refrigerated FluMist sprayer contains a single 0.2 mL dose with “live” attenuated influenza virus (10^6.5–7.5 FFU) from three strains: A/Norway (H1N1), A/Thailand (H3N2), and B/Austria (B/Victoria lineage).

Screenshot from FDA.gov taken November 5, 2024 showing FluMist vaccine package insert information explaining which live viruses are present in the drug.

Alarmingly, the FDA package insert indicates that the vaccinated can shed (or transmit) the vaccine virus onto the unvaccinated, potentially infecting them.

“Vaccine viruses capable of infection and replication can be cultured from nasal secretions obtained from vaccine recipients,” the document reads.

Vaccine virus shedding within 28 days of FluMist vaccination was studied in two multi-center trials: Study MI-CP129 (200 healthy participants aged 6 to 59 months) and Study FM026 (344 healthy participants aged 5 to 49 years).

In both studies, nasal samples were collected daily for the first 7 days, then every other day through Day 28.

In Study MI-CP129, participants with positive shedding on Day 25 or Day 28 had additional samples taken weekly until two consecutive samples tested negative.

Here’s a breakdown of the percentage of individuals in different age groups who tested positive for the FluMist vaccine virus at any point within 28 days of vaccination:

6-23 months: 89% tested positive for the virus
24-59 months: 69% tested positive
5-8 years: 50% tested positive
9-17 years: 29% tested positive
18-49 years: 20% tested positive

Screenshot from FDA.gov taken November 5, 2024 showing data on FluMist vaccine virus shedding across different age groups.

Screenshot from FDA.gov taken November 5, 2024 showing section 12.2 of the FluMist vaccine insert.

The FDA insert cites a study in a daycare setting that tested whether FluMist vaccine viruses can spread from vaccinated to unvaccinated children under age 3.

It confirmed that the vaccine can infect others, with documented transmission of a Type B virus from a vaccinated child to an unvaccinated child in the same playgroup.