Monday, March 07, 2011

Cochrane Researchers Weigh In On Getting A Flu Shot

Vaccines For Preventing Influenza In Healthy Adults, Cochrane Database of Systematic Reviews July, 2010
  • There are over 200 viruses and agents that cause influenza. The flu vaccine covers up to 15% of those.
  • "4% of unvaccinated people versus 1% of vaccinated people developed influenza symptoms." (So, 96% of people who didn't get a flu shot avoided getting the flu on their own, when exposed.)
  • "Vaccination had no effect on hospital admissions or complication rates."
  • "We found no evidence that vaccinations prevent viral transmissions."
  • "Inactivated vaccines caused local harms and an estimated 1.6 additional cases of Guillain-Barré Syndrome (a form of progressive paralysis) per million vaccinations."
  • "Industry funded studies were published in more prestigious journals and cited more than other studies independently from methodological quality and size."
  • "Studies funded from public sources were significantly less likely to report conclusions favorable to the vaccines."
This Cochrane Review included one of the largest collections of randomized evidence on influenza. It consisted of 36 trials, 15 of which were conducted by industry and, given the above, were likely biased. It still found no evidence of benefit for hospital admissions, flu complications, or transmission rates, and only a weak benefit for symptom reduction. I've been noncommittal about the flu vaccine thinking it doesn't hurt and might help. It's difficult to remain noncommital when an independent, international, evidence-based group of researchers says:
"The results of this review seem to discourage the utilization of vaccination against influenza in healthy adults as a routine public health measure."
Here's Tom Jefferson from the Cochrane Vaccines Field describing the findings:



Her Judiness said...

I like your blog. One observation: In the many 'food plans' I've used, 70 gms of protein would be calculated as 7 gms per ounce of food, so 70 gms or protein means 10 oz. of meat, for example. It's confusing, because writers of diet books often don't specify how they are using their measurements. Also, if you're totalling up your protein for the day, you must decide if you are going to count a serving of a grain as a protein or a starch - you don't count it as both. If you look at portion guides for diabetics, such as "Exchanges for All Occasions" you'll see that they want you to add items up by servings in categories - and I can't think of a food plan that had you add up all the protein or fat or carbohydrate gms in their entirety.

Steve Parker, M.D. said...

I feel better about skipping my flu shot for the last few years. And, as a physician, I'm exposed to a fair amount of flu.