The almighty influenza vaccine

A recent study in Clinical Infectious Disease that analyzed the effectiveness of the influenza vaccine for the 2014-15 season was sent to me by a colleague. Wow. Overall effectiveness (for influenza A and B combined) was a whopping 19%, but for influenza A was 6%. Honestly, placebo is more effective than that. For the 2015-16 season, overall effectiveness was 47%, and 55% for influenza A.

CDC used to cite that the flu vaccine was 70-90% effective, but more recently they have revised that significantly. I was quite surprised when I looked at the CDC website today and I made the graph below from their data.
In 12 consecutive flu seasons, effectiveness hit 60% just once. If you average those 12 seasons, the effectiveness was 41%. We are sorely in need of a better vaccine. The CDC analysis begs many questions: Should hospitals make this weakly effective vaccine a condition of employment? Should SHEA take another look at its guideline? Does anyone still believe that we should fire healthcare workers that are not vaccinated with a vaccine that provides such poor protection? How many hospitals fire employees who come to work sick with influenza? Would you rather be hospitalized at a hospital with a mandatory flu vaccine policy or a hospital that makes a serious attempt to minimize presenteeism?


  1. And once again I will observe that so many of the documented prevailing "flu season" viruses that can cause influenza like illnes are not influenza, but RSV, hMPV, rhinovirus, parainfluenza, adenovirus to name a few. Which makes me wonder about that data. Are ALL of the cases confirmed influenza? We sometimes treat all ILI as potential influenza (especially when there has been a confirmed case), and place people on Droplet Precautions when people sick with other viruses may require Contact Precautions as well. I really do have to get that case study/QA project data published. Thanks to Dr. Lance Peterson and Dr. Tommy Thompson we ran viral panels for 2 years and found multiple viral etiologies for what looked like a simple influenza outbreaks, with some people suffering from infections caused by multiple viruses. Spent lots of unnecessary money on Tamiflu until we figured this out. And THEN who are you protecting if you require non-vaccinated folk to mask when the prevailing respiratory strains are not influenza? We were working in a LTCF, but we kept sick people in Droplet/Contact (keeps people in their rooms in LTCF), used masking as a Standard Precaution related to respiratory etiquette which meant everyone masked in affected areas, hand hygiene,and emphasized keeping things and high touch surfaces clean and disinfected with low toxicity accelerated hydrogen peroxide that everyone could use. Not scientific, but the QA results showed it worked pretty well to stop respiratory and GI outbreaks in a single chain of LTCF. Lance, Mark Oliver and I presented at APIC- really have to get it into a paper.

    1. The CDC vaccine effectiveness data I cited used laboratory confirmed cases.

  2. Great post Mike. My take away from the 2015-2016 CDC powerpoint was that the vaccine was only 9% effective vs influenza A among age 50-64yo. If you are going to mandate influenza vaccine among healthcare workers, it should probably be effective in age groups that cover healthcare workers. Shouldn't pad effectiveness by adding in age 0-24, for example.

  3. Hi Mike, nice post and I completely agree, the low vaccine effectiveness and current strategy is not satisfactory ! My main question is: How many years are we away from introducting universal masking - the obvious solution - targeting also transmissions from asymptomatic carriers and ANY respiratry Virus ?
    Thanks, Rami


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