The Daily Beast is joining the anti-vaccination conspiracy mongering so beloved of the Huffington Post. With the usual dark threatening noises about the possibility of brain injuries to children, and references to mercury based vaccine preservatives, there’s this bit of astounding mathematical illiteracy:
the venerable flu shot is only 62 percent effective in reducing symptoms of the disease. In other words, for every 100 people who get the flu shot, 38 of them will get the flu anyway.
There are two ways of reading this number. One is: OH MY GOD! 38% OF PEOPLE WILL GET THE FLU! THAT HAS TO BE AN EPIDEMIC!* And, seeing as, on average, only 5-20% of the population gets the flu anyway, this means that the vaccination causes from almost double to seven times more people to get the flu than no vaccination at all! OH NO! THE FLU VACCINATION IS CREATING A FLU EPIDEMIC! WITH MERCURY!
The second way to read this immediately struck me: That author doesn’t know what that percentage means. It’s not 38% percent of the total vaccinated population will get the flu, it’s got to be that only 38% of whatever number would have got the flu anyway will get it if vaccinated. In other words, there’s a 38% reduction in the number of people who get the flu.
Not a giant increase.
The article cites the CDC for the 38% number. And here’s what the CDC says:
Findings from early data suggest that this season’s vaccine so far is reducing the risk of having to go to the doctor for influenza by about 60% for vaccinated people.
Yep. That would be a reduction in the number of people who have the flu. How many people are having the flu this year? The CDC says 5-20% of folks get the flu every year. So what this means is that, if, say, we would have had an epidemic of flu and 10% of the general population got it, only about 3.8% of the vaccinated population would get it. And that, of course, doesn’t account for the reduction of exposure from all those vaccinated folks who successfully avoided the flu.
It took only about 3 minutes to pull these numbers from the CDC site with a little Google aid.
The CDC is also good with the mercury nonsense. They note that the single-dose vaccination, which I got, does not contain themerisol (once the source of mercury in vacines, although not much any more) , and that the overwhelming scientific evidence demonstrates that thermerisol is safe.