A new study published in Pediatrics reports the nasal FluMist vaccine to be less effective in treating the flu as compared to the traditional flu shot.
Study authors combined data from 5 US studies and found of the 17,173 children aged 2-17 reviewed, the flu shot was 67% effective where as the nasal spray (FluMist) was only 20% effective and protecting against the flu.
FluMist is a live attenuated vaccine that is not recommended in infants and pregnant women. It is indicated for those between the ages of 2-49 and introduces a live, weakened version of the flu virus to incite an immune response. This differs from the injectable flu vaccine which uses killed versions of the flu strains to induce a flu response.
Children prefer the FluMist as the nasal spray offers a less painful option than an injection.
The US Centers for Disease Control and Prevention advisory committee voted last Fall to return the FluMist, nasal spray flu vaccine, to the recommended options for the 2018-2019 flu season.
In 2016 it was not recommended and discouraged as they found its effectiveness against seasonal flu to be approximately 46%, when 65% efficacy was touted by the injectable flu shot. However during the 2017-2018 flu season, the current flu vaccine was found to be only 35% effective with one of the worst flu seasons in years taking the lives of healthy young adults and children.
Why was last season so severe? The H3N2 strain was the predominant one, notorious for bad flu seasons, and is crafty, able to mutate before the vaccine is finalized. Hence our flu vaccine was not able to be as close a match as desired.
The panel voted 12-2 to include FluMist as an option for medical providers to recommend against the upcoming 2018-2019 flu season.
Why was FluMist removed? Experts found it to be ineffective against one of the influenza A H1N1 strains. With its overall efficacy found to be lower than the flu shot it was deemed a less ideal option than the shot.
This year the H1N1 strain appears to be more prevalent.
The FluMist Quadrivalent nasal spray, manufactured by MedImmune of AstraZeneca PLC, offers protection against 4 strains of flu including H1N1, H3N2 and two influenza B strains. According to FluMist’s prescribing information, the FluMist proved 90% effective against H3N2 as opposed to influenza B where it scored 44.3% effectiveness. Another review found its efficacy against H3N2 to be 79%.
Now that’s not to say the FluMist would have been immune to the vaccine issues experienced with last year’s flu shot as H3N2 is a highly virulent and mutable virus, and could have snowed the FluMist vaccine makers as well.
Yet we may need to consider that the FluMist may be more efficacious for some strains of the flu whereas the flu shot may better protect us against others. More research needs to be done in this area. As of now choosing which flu shot to get for the next flu season may be a crap shoot.
For more on the study click here.
Daliah Wachs, MD, FAAFP is a nationally syndicated radio personality on GCN Network, KDWN, and iHeart Radio.