Monday, October 4, 2010

Media Bias and The Pertussis "Epidemic"

I am constantly amazed at the inaccurate reporting that appears in major media sources, especially ones that are science oriented. In some cases it seems like there is a message that they want to get out and the facts are either ignored or forced into fitting the message.

Take for example the rhetoric about the pertussis (whooping cough) outbreak this year in parts of the country. If you were to follow what major media outlets are saying, you would believe that this is the worst outbreak in 50 years and that the reason for the outbreak is parents who are refusing vaccinations.

But, as I have talked about ad nauseum, the reality of the situation seems to be different.  It is true that parts of the country are experiencing outbreaks but, for the country as a whole, this is nowhere near the worst epidemic in 50 years. And more importantly, declining vaccination rates are only one possible explanation for the outbreak.

More likely reasons include the facts that pertussis outbreaks follow a cyclical pattern and happen every three to five years, that the number of pertussis cases have been on the rise since the 1980s, that the protection from the vaccine only lasts 10 years, or that there is evidence that the bacteria is changing the the vaccine simply isn't working as well. If you are interested in the details behind the facts, I would refer you to some of the earlier posts that I have written.

But none of these reasons seem to matter to the New Scientist in an article that they published a little over a week ago. The title of the article is "Whooping cough epidemic suggests bacteria are adapting" but the very first paragraph is as follows -
NINE babies have died in California, and four in Australia, so far, in the worst epidemic of whooping cough in rich countries since vaccination became widespread in the 1950s. The main cause is a lack of re-vaccination, but the bacterium may also be adapting to beat vaccines.
While the rest of the short article plays lip service to the idea that the there could be something else going on, the main theme is that the failure of people to use vaccines aggressively are behind the epidemic. Take for example the following statement -
Vaccination protects babies - these recent deaths have been in babies not yet vaccinated - but immunity wanes with age, so older children and adults can be unwittingly infected with whooping cough and infect unvaccinated babies.
While that statement is factually accurate, it leaves out one very important detail. The children who died didn't receive the vaccine because they were too young - not because their parents refused them. But this sort of nuance is completely absent from the reporting and has been replaced with an overriding "take your vaccines" message.

As for the assertion that this is "the worst epidemic of whooping cough in rich countries since vaccination became widespread in the 1950s", well I leave you with a pretty picture to dispell that notion.

The numbers on this chart are from the data published by the CDC and represent total number of cases week by week for the years 2004, 2005, 2009 and 2010. As you can see two years in very recent history have had far more cases at this point in the year.

1 comment:

  1. I really think the "epidemic" is mostly about selling the teen and adult version of the vaccine. Advertising wasn't working to sell the vaccine at the levels expected, so an "epidemic" was generated.

    Good analysis. Thanks for the coverage.