Contrarians Selling Magazines May Harm Your Health October 21, 2009Posted by Dwight Furrow in Dwight Furrow's Posts, Science.
Tags: media distorting science
Beware the contrarian looking for an angle to sell magazines.
This article in the Atlantic Monthly, entitled “Does the Vaccine Matter”, allegedly casts doubt on the effectiveness of flu shots. The article’s lede states:
In the U.S., the main lines of defense are pharmaceutical—vaccines and antiviral drugs to limit the spread of flu and prevent people from dying from it. Yet now some flu experts are challenging the medical orthodoxy and arguing that for those most in need of protection, flu shots and antiviral drugs may provide little to none. So where does that leave us if a bad pandemic strikes?
Here is an excerpt:
Study after study has found that people who get a flu shot in the fall are about half as likely to die that winter — from any cause — as people who do not….Yet in the view of several vaccine skeptics, this claim is suspicious on its face…..When researchers from the National Institute of Allergy and Infectious Diseases included all deaths from illnesses that flu aggravates, like lung disease or chronic heart failure, they found that flu accounts for, at most, 10 percent of winter deaths among the elderly. So how could flu vaccine possibly reduce total deaths by half? Tom Jefferson, a physician based in Rome and the head of the Vaccines Field at the Cochrane Collaboration, a highly respected international network of researchers who appraise medical evidence, says: “For a vaccine to reduce mortality by 50 percent and up to 90 percent in some studies means it has to prevent deaths not just from influenza, but also from falls, fires, heart disease, strokes, and car accidents. That’s not a vaccine, that’s a miracle.”
….The history of flu vaccination suggests other reasons to doubt claims that it dramatically reduces mortality. In 2004, for example, vaccine production fell behind, causing a 40 percent drop in immunization rates. Yet mortality did not rise. In addition, vaccine “mismatches” occurred in 1968 and 1997: in both years, the vaccine that had been produced in the summer protected against one set of viruses, but come winter, a different set was circulating. In effect, nobody was vaccinated. Yet death rates from all causes, including flu and the various illnesses it can exacerbate, did not budge.
But this article doesn’t deliver what it promises
Notice first, that the entire article is about mortality rates from the flu. But most of us get flu shots to avoid getting sick and losing a week of work. The chances of an otherwise healthy person dying from the flu are not great. Yet, the article never addresses the effectiveness of flu shots at preventing or moderating the flu. There are all sorts of reasons why an effective flu vaccine might fail to significantly influence mortality rates especially among the elderly. The main reason is that people with compromised immune systems, who are at greater risk of dying from all sorts of causes, will not benefit from the vaccine because their immune systems are compromised.
Mortality rates may not be a reliable indicator of effectiveness at preventing the flu.
Secondly the claim that “they found that flu accounts for, at most, 10 percent of winter deaths among the elderly” cannot be used to cast doubt on the data supporting the vaccine’s effectiveness—the fact that “people who get a flu shot in the fall are about half as likely to die that winter — from any cause — as people who do not”. The author is illicitly comparing two different populations—the elderly with all people who get flu shots.
Thirdly, there may be natural immunity that explains why incidence of the flu drops in years when less vaccine is available.
Finally, it may well be the case that healthy people tend to get vaccinated more readily than unhealthy people, thus providing an alternative explanation of why vaccinated people suffer less mortality. But the only way to test that claim is to compare two populations that have all relevant characteristics in common except for the fact that one population was vaccinated and the other not. But the article provides no data of that sort.
The medical professionals cited in the article may have good reasons for challenging the conventional wisdom of vaccine effectiveness. But if they do, this article doesn’t convey those reasons.
It is probably a good thing that professions count within their ranks contrarians who are trying to make a name for themselves by challenging conventional wisdom. Sometimes they turn out to be right.
But when the media presents speculative, untested, minority positions as serious challenges to the consensus, they mislead their readers.
For political commentary by Dwight Furrow visit: www.revivingliberalism.com