Tuesday, November 10, 2009

Does the Vaccine Matter?

This is quite a lengthy article, definitely worth reading in it's entirety.
I'll excerpt some interesting parts.

Drive too fast along Red Lion Road, beside Philadelphia’s Northeast Airport, and you will miss the low-rise cement building where the biotech company MedImmune has been quietly pumping out swine flu vaccine at about a million doses a week. Through the summer and fall, workers wearing protective gear that covered them from head to toe brewed up batches of live, genetically modified flu virus. Robots then injected tiny doses of virus-laden fluid into glass vials, which were mounted into nasal spritzers, labeled, and readied for shipment at the direction of the Centers for Disease Control and Prevention, in Atlanta, which is helping to coordinate the nation’s pandemic-preparedness plan. In the most ambitious vaccination program the nation has mounted since the anti-polio campaign in the 1950s, the federal government has commissioned MedImmune and four other companies to produce enough vaccine to cover the entire U.S. population..........

But what if everything we think we know about fighting influenza is wrong? What if flu vaccines do not protect people from dying—particularly the elderly, who account for 90 percent of deaths from seasonal flu? And what if the expensive antiviral drugs that the government has stockpiled over the past few years also have little, if any, power to reduce the number of people who die or are hospitalized? The U.S. government—with the support of leaders in the public-health and medical communities—has put its faith in the power of vaccines and antiviral drugs to limit the spread and lethality of swine flu.

Yet some top flu researchers are deeply skeptical of both flu vaccines and antivirals. Like the engineers who warned for years about the levees of New Orleans, these experts caution that our defenses may be flawed, and quite possibly useless against a truly lethal flu. And that unless we are willing to ask fundamental questions about the science behind flu vaccines and antiviral drugs, we could find ourselves, in a bad epidemic, as helpless as the citizens of New Orleans during Hurricane Katrina

The term influenza, which dates back to the Middle Ages, is taken from the Italian word for occult or astral influence. ( I thought that was in interesting little factoid) Then as now, flu seemed to appear out of nowhere each winter, debilitating or killing large numbers of people, only to vanish in the spring. Today, seasonal flu is estimated to kill about 36,000 people in the United States each year, and half a million worldwide.

Yet the flu, in many important respects, remains mysterious. Determining how many deaths it really causes, or even who has it, is no simple matter. We think we have the flu anytime we fall ill with an ailment that brings on headache, malaise, fever, coughing, sneezing, and that achy feeling as if we’ve been sleeping on a bed of rocks, but researchers have found that at most half, and perhaps as few as 7 or 8 percent, of such cases are actually caused by an influenza virus in any given year. More than 200 known viruses and other pathogens can cause the suite of symptoms known as “influenza-like illness”; respiratory syncytial virus, bocavirus, coronavirus, and rhinovirus are just a few of the bugs that can make a person feel rotten. And depending on the season, in up to two-thirds of the cases of flu-like illness, no cause at all can be found.

Flu comes and goes with the seasons, and often it does not kill people directly, but rather contributes to death by making the body more susceptible to secondary infections like pneumonia or bronchitis. For this reason, researchers studying the impact of flu vaccination typically look at deaths from all causes during flu season, and compare the vaccinated and unvaccinated populations. Such comparisons have shown a dramatic difference in mortality between these two groups: 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. Get your flu shot each year, the literature suggests, and you will dramatically reduce your chance of dying during flu season.

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 estimate of 50 percent mortality reduction is based on “cohort studies,” which compare death rates in large groups, or cohorts, of people who choose to be vaccinated, against death rates in groups who don’t. But people who choose to be vaccinated may differ in many important respects from people who go unvaccinated—and those differences can influence the chance of death during flu season. Education, lifestyle, income, and many other “confounding” factors can come into play, and as a result, cohort studies are notoriously prone to bias. When researchers crunch the numbers, they typically try to factor out variables that could bias the results, but, as Jefferson remarks, “you can adjust for the confounders you know about, not for the ones you don’t,” and researchers can’t always anticipate what factors are likely to be important to whether a patient dies from flu. There is always the chance that they might miss some critical confounder that renders their results entirely wrong.

When Lisa Jackson, a physician and senior investigator with the Group Health Research Center, in Seattle, began wondering aloud to colleagues if maybe something was amiss with the estimate of 50 percent mortality reduction for people who get flu vaccine, the response she got sounded more like doctrine than science. “People told me, ‘No good can come of [asking] this,’” she says. “‘Potentially a lot of bad could happen’ for me professionally by raising any criticism that might dissuade people from getting vaccinated, because of course, ‘We know that vaccine works.’ This was the prevailing wisdom.”

Nonetheless, in 2004, Jackson and three colleagues set out to determine whether the mortality difference between the vaccinated and the unvaccinated might be caused by a phenomenon known as the “healthy user effect.” They hypothesized that on average, people who get vaccinated are simply healthier than those who don’t, and thus less liable to die over the short term. People who don’t get vaccinated may be bedridden or otherwise too sick to go get a shot. They may also be more likely to succumb to flu or any other illness, because they are generally older and sicker. To test their thesis, Jackson and her colleagues combed through eight years of medical data on more than 72,000 people 65 and older. They looked at who got flu shots and who didn’t. Then they examined which group’s members were more likely to die of any cause when it was not flu season.

Jackson’s findings showed that outside of flu season, the baseline risk of death among people who did not get vaccinated was approximately 60 percent higher than among those who did, lending support to the hypothesis that on average, healthy people chose to get the vaccine, while the “frail elderly” didn’t or couldn’t. In fact, the healthy-user effect explained the entire benefit that other researchers were attributing to flu vaccine, suggesting that the vaccine itself might not reduce mortality at all. Jackson’s papers “are beautiful,” says Lone Simonsen, who is a professor of global health at George Washington University, in Washington, D.C., and an internationally recognized expert in influenza and vaccine epidemiology. “They are classic studies in epidemiology, they are so carefully done.”

The results were also so unexpected that many experts simply refused to believe them. Jackson’s papers were turned down for publication in the top-ranked medical journals. One flu expert who reviewed her studies for the Journal of the American Medical Association wrote, “To accept these results would be to say that the earth is flat!” When the papers were finally published in 2006, in the less prominent International Journal of Epidemiology, they were largely ignored by doctors and public-health officials. “The answer I got,” says Jackson, “was not the right answer.”

Like I said, read the rest at the link as this is less then one third of the article.


  1. Thanks Pen, that was brilliant. And hats off to Liza Jackson.

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