Public Health is in a bit of a pickle over the nasal flu vaccine

About a week ago, the CDC Advisory Committee on Immunization Practices voted to not recommend the use of the Live-Attenuated Influenza Vaccine (LAIV). This vaccine is given as a spray up each nostril and it is sold as FluMist in the United States. Here’s what the reasoning was:

“In late May, preliminary data on the effectiveness of LAIV among children 2 years through 17 years during 2015-2016 season became available from the U.S. Influenza Vaccine Effectiveness Network. That data showed the estimate for LAIV VE among study participants in that age group against any flu virus was 3 percent (with a 95 percent Confidence Interval (CI) of -49 percent to 37 percent). This 3 percent estimate means no protective benefit could be measured. In comparison, IIV (flu shots) had a VE estimate of 63 percent (with a 95 percent CI of 52 percent to 72 percent) against any flu virus among children 2 years through 17 years. Other (non-CDC) studies support the conclusion that LAIV worked less well than IIV this season. The data from 2015-2016 follows two previous seasons (2013-2014 and 2014-2015) showing poor and/or lower than expected vaccine effectiveness (VE) for LAIV.”

If you’ve been a reader of this blog for a while, you should know that I don’t think there are any sacred cows when it comes to vaccines. In essence, I don’t blindly defend vaccines, contrary to what the antivaxxers claim. You should also know that we — epidemiologists — kind of saw this problem coming, especially after the Center for Infectious Disease Research and Policy published a report where the main conclusion was that we need a game-changing vaccine against influenza because what we have right now is not nearly as good as we need it to be. I mean, for crying out loud, a 3% effectiveness?

Effectiveness, by the way, is the real-world protection a vaccine provides. Efficacy is what the clinical trials (under near-perfect conditions and with a very homogenous population) tell you about the vaccine. Here’s a really good presentation from WHO on how these two concepts are used in vaccine policy.

Anyway, this recommendation against the LAIV puts public health in a bit of a pickle because it’s a vaccine that, for the most part, is marketed for use with children (although it can be used for anyone between 2 and 49 years of age). Because it doesn’t involve a shot with a needle, a lot of parents ask for it for their children, and a lot of children are okay with taking it.* Also, because many schools have policies against forcefully restraining a child, they’re more amenable to giving the LAIV over the injected vaccine. (Some kids are much stronger than they seem when it comes to holding them in place for a needle in the arm.)

In other words, no fuss, no muss.

So what does public health do now? Do they continue with the vaccine clinics in the fall as scheduled knowing that there will be people who will not want the injectable vaccine for their children? Do they cancel the clinics and just hope that parents will talk it over with their pediatricians on whether or not to get the LAIV although it’s not recommended? And what about insurance companies? Will they pay for the LAIV when it is not recommended this upcoming season?

What’s really complicated is that this all has to be communicated to everyone in a way that is understandable. We in public health need to explain efficiency and effectiveness, the science of the flu vaccine in general, the science of the LAIV versus injectable vaccines, and why the LAIV may come back next year. Sprinkle on top of that the fears that antivaxxers bring to the party and…

And it’s going to be an interesting flu season.

*This is anecdotal because I’m not able to get the numbers right now. But, trust me, A TON of parents ask for the spray over the shot for their kids.

4 Comments on “Public Health is in a bit of a pickle over the nasal flu vaccine”

  1. At 3%, I wonder even how that vaccine ever was approved or even made it out of the plant door.
    Oh well, at least we have the 63% effective vaccine, may they get that up to at least the high 80 percentages soon.


    • It was higher for a long time, and was even better than the injectable in younger age groups some years. It’s been getting bad in the last couple of years. My theory is that the viruses they use are adapted to not grow in warm areas of the body (i.e. the lungs) but do grow in cooler areas (like the nasal cavity) and this has some effect on the immune response. But that’s just me.


      • Wasn’t there also something about the quadrivalent version, suspicion that perhaps the way the additional serotype was processed resulted in lower overall effectiveness?


        • Yes. I forgot about that part. Why you don’t see that effect in the injectable is maybe due to the delivery method as well. One thing is for sure, there’s going to be a lot of confusion and long meetings at local health departments on what to do. Which reminds me… I have a meeting to go to. :-p


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