Why "Herd Immunity" is Moot in Seasonal Flu or Swine Flu
Posted Sep 23 2009 10:36pm
Recently, I posted an LA Times article to my Facebook page about parents who, due to safety concerns, will likely decline the Swine/H1N1 Flu vaccine for themselves and their children . When my Facebook friends posted their reactions to this article, safety concerns were ignored in favor of a slew of responses about striving for herd immunity . It seemed they had already done a risk-benefit calculation, reasoning if some were hurt by the vaccine, herd immunity was more important. (See bottom of article for a back-of-the-envelope analysis of risk-benefit.) But, what they didn't realize in these arguments is that herd immunity is a moot point when it comes to the flu and flu vaccine.
So to address the cries for herd immunity, I offer you some data points:
Herd immunity occurs when 80-90% of a population has a theoretically protective level of antibodies, either from mounting an antibody response to an antigen in a vaccine or from suffering through a virus and recovering.
Only 30-40% of people get the Seasonal Flu vaccine - far short of herd immunity.
Seasonal flu mutates and changes every year, so there are not years and years of vaccinating people against the same disease to ratchet coverage up to the 80-90% level.
Due to mutations, a seasonal (or swine flu) shot that is developed in advance of flu season may not match the circulating flu viruses. In at least half of the flu seasons, there is no virus-vaccine match, leaving 0% of the population with theoretically protective levels of antibodies.
The Cochrane Collaboration reviewed ALL flu shot studies - decades worth of data - and found that if you get the virus for which you were vaccinated, you will be sick only 0.16 of a day less (4 hours) than if you didn't get the shot. I.e. the flu shot does not work . Tom Jefferson MD, the independent reviewer analyzing all flu shot studies found this in 2006 , upon completion of his team's review: "Only among people who suffer bronchitis could he find good evidence that flu vaccination was worthwhile. In infants up to two, vaccination was no better than placebo and in older children there was little evidence of benefit. Nor could he find enough evidence of benefit among people with chronic chest problems, asthma and cystic fibrosis. In healthy adults the best evidence was that, on average, flu vaccination of a population would prevent 0.1 per cent of a working day lost. Combined studies of the elderly showed a variation from no effect to a 60 per cent difference when "all cause mortality" was measured."
Optimism Bias: because other vaccines seem to work, people, MDs included, assume the flu shots must work, too. (See point 5)
Recency Bias: A single recent study seems to prove flu vaccines do work. Average that single study into the other 48. (See point 5)
People who worry about protecting others in "the herd" from the flu do not have the correct information about flu shot efficacy. (See point 5)
Finally, if you are so worried about a flu virus and still believe the Seasonal Flu Vaccine offers protection, then get vaccinated and you can believe you are protected from those who don't get the vaccine. That's called the placebo effect. Enjoy it.
Vitamin D: Normalizing your blood levels of Vitamin D strongly protects against ALL VIRUSES. There are no known safety issues for the D3 form and it's less expensive ($20 per bottle per year) than the flu shot.
A few thoughts on the Swine Flu (H1N1) vaccine
The CDC says the Swine Flu (H1N1) vaccine is based on the Seasonal Flu vaccine manufacturing processes. (I attended the Swine Flu public engagement meeting with the CDC in Sacramento.)
The Swine Flu virus can mutate. If it does, the vaccine developed on a July strain isolated in California will be rendered useless. There won't be a virus-vaccine match.
In addition to the injection, a live attenuated nasal spray will be available. Again, this makes people shed virus . They are contagious with an estimated transmission rate of 1 - 2.4%. This works against herd immunity. If the entire herd were vaccinated this way, then roughly five million Americans would spread the virus the vaccine is intended to prevent. Each of those people would then spread it, too. Think about that.
Though this post is about efficacy, the estimates for Swine Flu vaccine safety are based on the 1976 Swine Flu vaccine. According to the 60 Minutes episode on the 1976 Swine Flu Fiasco, of the 40 million who were vaccinated for Swine Flu that year, 4,000 shot recipients filed claims for injury or death - a 1 in 10,000 chance of a severe adverse reaction*. Again, if the entire herd is vaccinated, are we willing to accept that 30,000+ Americans will get Guillain-Barre Syndrome or die? This is a mild flu. The cost-benefit is not working out for me.
Once again, check your levels of Vitamin D, the sunshine vitamin. It's cheaper, easier, and safer to avoid all viral illness by maintaining a normal blood level of Vitamin D. At least half of us are deficient, which is the main cause of "Flu Seasons" in the winter.
If you do get a virus, you can treat it with high doses of Vitamin D for seven days after onset of symptoms. My friend K.A. tried this last week when she came down with a bad flu and she wrote, "It really worked...I took just 4 [16,000IU of D3] and it worked... it was miraculous....I was on the mend and so surprised!" See the Vitamin D Council for instructions. Always consult your doctor.
Happy flu season!
*NB: I have corrected some data from the first version of this article. The CDC has revised the 1976 injury rate down to 1 in 100,000 based on claims eventually paid out. You can guess the myriad political reasons why that number was revised sharply downward. In reality, it is known that vaccine adverse reactions are strongly under-reported, by a factor of two to ten, due to the nature of the passive surveillance system. If half the severe adverse events were not reported, then the initial 1976 Swine Flu injury claims could have been 8,000, making the risk odds 1 in 5,000.