How Vaccines Went from Life-Saving to Dangerous

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It is very easy for us, living in the sanitized Western hemisphere, to forget how thoroughly modern medicine has changed our lives. A cut turned septic is no longer a death sentence and is easily treated with antibiotics. We no longer have to fear for ourselves and our family as plague tears through the community. Infectious disease is no longer the main cause of death in America and Europe, as it once was.

In large part we have to thank vaccination for this miraculous progress. But in recent years, vaccination has come in for some harsh criticism. The combined MMR vaccine in particular has been claimed to cause autism. Where did these claims come from, and is there any truth in them? And, most importantly, should we still be vaccinating our children?


Photo by DFID - UK Department for International Development (Flickr)

The most striking example of what vaccination has achieved is with a disease that used to cause death and suffering on a colossal scale -- the smallpox. This virus used to devastate communities approximately once a generation. It killed over 300 million people in the 20th (yes, 20th!) century and many more in previous centuries. It left a large proportion of its victims dead and many more horribly disfigured. Yet since 1977 the virus has been extinct in the wild (the USA and Russia keep the last remaining stocks in deep freeze). Barring any deliberate release of these stocks, the virus will one day also be extinct from our collective memory. Good riddance!

Those who caught smallpox but survived were immune to re-infection. It is for this reason that the virus only spread every thirty years or so -- you needed a new generation of people who had never been exposed to the virus before an epidemic could take hold. The key observation was that milkmaids, who often contracted the less severe disease cowpox, did not suffer from smallpox. In a remarkable (and by today's standards completely unethical) experiment in 1796, an English physician, Edward Jenner, infected an eight-year old boy with cowpox. He then tried to infect the lad with smallpox. Fortunately, the boy was immune and within years vaccination (from the Latin vacca, which means "cow") was common practice.

Since then, vaccines have been developed against many of our most important infectious diseases. It is hoped that poliovirus will soon become the third virus extinction (the second was rinderpest, a disease of cattle). Many of the vaccinations in a modern child's programme are against diseases that are comparatively less severe, such as the combined MMR vaccine which protects against measels, mumps and rubella.

These may not sound like the scariest diseases around but with a fatality rate of 0.3 percent for measles, a risk of infertility in males who are infected with mumps and severe complications for pregnant women and their unborn children infected with rubella, the benefits start adding up. In large populations like America, the number of deaths and hospital stays prevented by vaccination with MMR is enormous, not to mention the financial savings of hospital care, days off work, etc.

So what is the MMR scare? In 1998 Andrew Wakefield, a doctor in London, published an article in which he described 12 children who had received the MMR vaccine and were diagnosed with autism. Finding 12 such kids should not come as a huge surprise since MMR vaccination had been widespread in England for the preceding decade and autism is a relatively common condition. Finding associations between very rare conditions is more noteworthy: in the words of medical journalist Ben Goldacre, "If everyone who went into space came back with an extra finger, say, then that would be worth noting."

The article that Wakefield published, known as a "case series report" simply stated that this might be worth looking into. Several groups did just that and reported no increase in the risk of autism in MMR vaccinated kids. This is the way science is supposed to work: identify a hypothesis (MMR causes autism), design an experiment (examine the rates of autism in children with different vaccination backgrounds), come to a conclusion (no, MMR does not cause autism).

But the damage was done. The British press went to town on it. Every press conference that Wakefield held was given blanket media attention, whilst publication of results that showed there were no links were ignored. Even the more reputable newspapers pushed the controversy as their headlines. Then, when Tony Blair, then prime minister, refused to state whether his youngest son had been vaccinated, the story went crazy.

As a consequence, uptake of the MMR vaccine in Britain dropped from 92 percent in 1997 to below 80 percent in 2004. A mumps epidemic ensued in 2005 with 43,000 confirmed cases. The outbreak had a sobering effect and the media finally gave up on the story.

Vaccination levels are now recovering though not yet back to mid-1990’s levels. Andrew Wakefield has since been shown to have acted dishonestly in the way he collected his original data and has been struck off as a practicing doctor in Britain (he has now relocated to the U.S.). The press, looking for someone to blame for the folly, has also turned its ire on him as a rogue doctor who mislead them for his own benefit. In reality, it was the media's own determination to spin and sell a story that caused most the damage.

Vaccnine scares aren't new: Jenner's first vaccine met with much resistance after the vaccine was found to have a risk of severe side effects. There have been other scares in France (with reports that the hepatitis B vaccine causes multiple sclerosis) and the U.S. (that the preservative thiomersal causes autism), both of which have been discredited. As a precaution thiomersal has been removed or diminished in most vaccines.

Of course, there are even more outlandish conspiracy theories that involve the government placing tracking devices in citizens. The MMR controversy was largely confined to Britain and seems to have had little effect in the U.S. Yet, with a vocal anti-vaccinationist movement there is a risk that America could follow Britain's erroneous lead, whether its about MMR or a controversy of the future.

It is alarming, for instance, that one in 10 parents of young children follow an 'alternative' vaccination schedule. Whenever the safety of a vaccine is in question, the only thing we can do is look to the evidence. In the case of MMR, the concerns were unfounded. What we can emphatically say is that the vaccine saves thousands of preventable hospital visits and innumerable deaths every year. You're much better off with it than without it.

William McEwan is a virologist who studies the body's fight against virus infection. He investigates how cells can detect and destroy viruses as a last line of defense. He gained a PhD from the University of Glasgow in 2010 and is currently based at the Medical Research Council Laboratory of Molecular Biology in Cambridge, UK. He tweets as @w_mcewan.

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