The flu vaccine is super-duper effective… I guess.

Merck makes the flu vaccine Afluria and and it’s like the greatest thing under the sun. (Yeah… but not greater than the sun!)

When everybody talks about how effective the flu vaccine is, it’s so interesting because people just assume that they will automatically get the flu without the vaccine. I know I’ve fallen victim to this idea for no good reason except  media hype, though I’ve never gotten a flu vaccine.  But check this out. When you actually look at the numbers, a person’s chances of getting the influenza in one flu season aren’t even that great anyway if Merck’s study truly represents flu contraction statistically.

I made you a graph based on their numbers so you can see. This is the percentage of people in their study that ended up with positive flu cultures over the course of that flu season after they waited two weeks for the vaccine to start its awesomeness:

how effective is the flu shot

(These were mostly white women with a mean age of 35.5 yrs, just in case you were wondering.)


I mean, I know I’m not a doctor,but that’s not too terribly impressive to me. I guess you have to decide for yourself.

On the other hand, check out what the graphs look like when you compare vitamin D supplementation to a placebo group. This particular study references African Americans, so keep that in mind as without supplementation, African Americans are more likely to be deficient in vitamin D. This study is reported incidences of cold and flu, because no lab tests were offered as this study’s original intent was simply to monitor bone density. Cold and flu were just extra information gathered to consider adverse reactions. This test period also lasted over the course of 3 years. So while it’s a much smaller test group, it’s especially cool because it lasted a long time and it wasn’t about the flu, so there’s less chance of influence factoring in. It should also be noted that once the level of vitamin D supplementation went up to 2000IU from 800IU halfway through the study, the reported incidence of cold or flu was less than 1%.

influenza vitamin d

“One of the reasons that so many young people died in the 1919 epidemic was once the 1919 virus infected you, it made you sick, but your immune system would make you even sicker because it would mount this inappropriate all-out attack that killed not just the virus, but also many of the respiratory cells in your respiratory tract. The victims had their respiratory tracts denuded of epithelial cells. Doctors had never seen this before. Vitamin D works in many ways in the immune system. Antimicrobial peptide production is just one of them. What vitamin D does is make your immune system smarter, not stronger. If your immune system becomes too strong, you can get autoimmune diseases. What is important about vitamin D is that it makes your immune system smarter.” –John Cannell, M.D.*

“WARNING: Adverse reactions may include a lessened ability to honestly ‘call in sick’ to work. People who hope to acquire the flu or a cold should seriously consider not taking this dietary supplement.”

So, while I can’t say that taking vitamin D can be used as a preventative for the flu in place of the vaccine, because the FDA frowns on that kind of thing, I’m considering complaining to the FDA that my bottle of vitamin D3 doesn’t have all of its adverse reactions listed on it. That’s highly irresponsible.



*In 2006, Dr. Cannell’s article, “Epidemic Influenza and Vitamin D” was published in the journal, Epidemiology and Infection. The article, co-written by some of the world’s top vitamin D experts, presented a revolutionary new theory on vitamin D’s link to the flu. This quote was taken from an interview with Dr. Passwater from WholeFood’s Magazine in 2011.

Disclaimer: I’m not a medical doctor, or any doctor, so this is not to be considered medical advice. The FDA has approved no statements encouraging the use of vitamin D to support resistance to influenza in any way. The FDA & CDC recommends almost everyone get an annual flu shot.

 Photo credits: We made the graphs ourselves. Feel free to use them in your own articles, just give credit to


  1. Kelly

    I take vitamin D. Daily because osteoporosis is a factor in my family. I am sick constantly as I have a daughter in preschool. I have not noticed any increase in my immune system due to the Vit d. Nice try though:)

    • Dawn Babcock Papple

      How much do you take and what kind of vitamin D do you take? It might suit you to get your blood tested to see if you are deficient. Needs vary tremendously based on how much a person is outside, if they tan, where they live and the color of their skin. For example, I take around 6000IU daily in the winter because of where I live. I make sure to take the D3. Kelly, I’m not “trying,” there are numerous studies that will back this up. Also, vaccinations are often implicated in depressing a person’s immune system. I can’t really get into the nitty gritty of that, but if you are interested in learning more, I can direct you to medical professionals where you can find medical information on that.

      In addition to these things, if you are taking any coticosteroid steroids (like prednisine,) ulcer meds (like
      Tagamet, Pepcid, Zantac, Axi) or some Cholesterol meds ( like Cholestyramine, Colestipol) you will need more vitamin D as well because these deplete your body’s reserves.

      Likewise, if you eat a diet very low in animal fat, your will deplete Vitamin D.

      Some people need over 10000IU each day to be where they need to be. A blood test from a doctor can help you figure this out. You can’t say that you take vitamin D and still feel crappy so this theory is bunk until you’ve checked to see where your are.

      Of course, other vitamins are also helpful like large amounts of vitamin C from natural sources too. Vitamin D however is the most common way for us to boost our immune system.

      Let me know if you’d like information on sources and as your doctor to do a blood test. If you’d like me to show you more studies or medical doctor commentary on the subject, I will be happy to do that as well.

  2. Katie

    You can’t look at a study that was designed to look at something to completely different and get a result. This doesn’t control varying factors better, and you certainly can’t apply it to the general population if it only looked at one ethnic group. The best you can say is that something is worth looking into in further research. Also, I’m not sure how much you know about statistics, and I’m certainly no expert, but you can’t compare straight percentages to see whether something is worthwhile (as in, “statistically significant”). And, in the end, the flu can be deadly. Not to the average 35 year old woman, maybe, but to their infants who are too young to get the flu shot and the elderly that they may work around or live with. For this reason, I’ll continue to get a flu shot, to protect my son and my grandparents. I also take Vitamin D, as I am deficient, but people should definitely get tested to find out what dose of D they should be taking – it is not something you should take too much of. It is a fat soluble vitamin and there are side effects. As far as the type of D – D3 is the OTC kind. I don’t think I’ve ever seen another kind in a supplement, but obviously I haven’t seen all the supplements in the world. The prescription Vitamin D product is actually D2. I have read that either D2 or D3 are added to milk.

  3. Pingback: The “Autism and Flu Correlation” study and its inevitable use in marketing the flu shot. — Everything Birth's Blog on Midwifery, Attachment Parenting, Cloth Diapers and More

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