10 things you should know about Measles and Vaccination

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Measles is back. Ok – it never really went away. In 2012, 122000 people died from measles, worldwide. That’s quite a lot of deaths. Most of them were children, aged under 5. It’s actually part of an improving trend, compared to 562000, which is how many people died from measles in 2000.

The thing that makes measles deaths different to, say, deaths from cancer, or ebola, is that measles is a preventable illness. We have a vaccine which can control it and prevent it from spreading. But in the developing world, not everyone has access to it. And where people do have access, not everyone wants it.

The internet is full of pro-vaccine rants and anti-vaccine rants.

It’s simple, say the “pro” camp. Vaccines are safe. Illnesses are dangerous. People who don’t vaccinate are stupid. This is an avoidable epidemic.

There is more. Some people can’t have vaccines. This includes some people with other illnesses, and newborn babies. Everyone in this group is particularly at risk of complications if they do develop an infectious disease. They rely on “herd immunity”. If everyone they come in contact with is vaccinated, no-one can pass the illness on to them. This group doesn’t have the option of a vaccination.

What of the other side of the argument? There are several reasons why people turn down vaccines.

Some people believe vaccines are dangerous, and cause illnesses (such as autism, bowel problems, learning difficulties, and a long list of others).

Some believe vaccines are best avoided because they are not “natural”, and contain chemicals that are best avoided.

Some have religious objections

Perhaps the majority of people who turn down vaccines don’t know very much about it. They may have heard some negative things about vaccines. They may have a feeling that agreeing to vaccinate their children is a riskier choice than refusing.

Here are 10 facts you ought to know if you’re wondering which side of the debate you agree with. I’ll try not to be controversial.

  1. Measles is dangerous.

Measles doesn’t sound serious. It’s easy to forget, from our privileged modern perspective, that measles was a killer disease all over the world before vaccination. In many places in the world, it still is. In 2012, an estimated 122,000 deaths occurred due to measles worldwide. The majority of these cases were in Africa and Asia, where vaccination rates are low and the illness is common. The deaths are not simply due to poor healthcare in people contracting measles. Deaths occurred in countries with excellent healthcare systems (UK, France, Germany, Italy etc). If the current epidemic spreads in America, people will die there too. If you get measles, your chances of dying may be as much as 1 in 3000 (it’s difficult to come up with an exact figure, since measles epidemics are rare in countries with advanced health care systems, because of vaccination!). There are about 3.5 million children under five in England and Wales. Measles is very highly infectious. If none were immunised and all got measles, we could expect 1000 dead children under five.

  1. Once you’ve got measles, modern medicine doesn’t have a lot to offer

Measles is a virus. It is not treatable by antibiotics, or any other specific medicine. Treatment is supportive. Deaths are often sudden, from complications such as pneumonia or encephalitis.

Encephalitis, or inflammation of the brain, affects about 1 in 1000 people who get measles, and leads to seizures, brain damage, and sometimes death. It’s a truly horrible thing to watch, knowing that it could have been prevented.

  1. Immunisation is very effective.

Measles vaccination works very well. There is very strong evidence on this score. In countries with more than 95% of people vaccinated, spread of measles is almost impossible. Not everyone achieves perfect immunity, but enough people do that the virus can’t spread. Recent epidemics in vaccine-using countries have all occurred in pockets of the population with low vaccine uptake (such as California).

Measles is extremely infectious – much more than ebola, for example. Stopping transmission any other way is very difficult, perhaps impossible.

  1. Having a measles vaccination is less risky than having measles.

Many pro-vaccine articles simply say MMR is safe. It is very safe compared to many other medical interventions, but there are risks. Some people are allergic to it, or to components of it. It probably does increase the risk of suffering from some rare inflammatory problems, for example a condition called thrombocytopenia purpura. This is a potentially serious condition, although vaccine related cases are generally reported as milder than other cases. The risk of this complication after MMR is about 1 in 22000 cases, or 0.005%. If that puts you off the vaccine, it’s worth noting that there is a much higher chance of getting thrombocytopenia purpura as a complication of measles itself.

You can read about a summary of side effects of MMR from a collected group of nearly 15 million reported patients here:

http://www.ncbi.nlm.nih.gov/pubmed/22336803

Death rates from measles, despite the best medical care, are probably about 1 in 3000. Living in a country with good healthcare is not enough to protect you if you are unvaccinated.

Deaths from the vaccine – well, if you google MMR and death you’ll find plenty written about this. But a proven increase in death rates following vaccination, no.

Any parent considering skipping their child’s vaccinations should know this. Your child might have side effects from their vaccine. They might have fever, pain at the injection site. They might even have one of the very rare serious adverse reactions. But if you decide not to vaccinate them, this course of action also has potential side effects, the side effects of actually having measles. They probably won’t occur immediately, or within days or weeks of not getting vaccinated. But these side effects are likely to be worse.

  1. If a child has a vaccine, and then becomes ill, it isn’t necessarily the fault of the vaccine

You don’t have to look hard on the internet to find many many similar tales of children who had vaccinations and then got ill. You’ll hear about children who seemed normal then had a vaccine, followed by a fever, followed by seizures and learning difficulties. These children never get back to normal. The medical profession gave this a name – vaccine encephalopathy, meaning vaccine-related brain damage. Some of these families received big pay-outs from the vaccine companies.

And then, researchers made an interesting observation. People with vaccine encephalopathy had a lot in common with people with another condition, which at the time was called Severe Myoclonic Epilepsy of Infancy. These people developed normally for the first months of life, but then began to have seizures, and development slowed down or even went backwards. The first seizure often seemed to happen when the child had a fever.

When a genetic cause was discovered for SMEI, Australian researchers decided to look for the same genetic problem in 14 people with vaccine encephalopathy. They found that 11 of the 14 had the same genetic mutation. The condition is now called Dravet Syndrome.

Here is a summary of their paper:

http://www.ncbi.nlm.nih.gov/pubmed/16713920

This has been duplicated elsewhere.

So, in fact, vaccine encephalopathy is not caused by vaccines. It’s genetic, caused by a copying error in the DNA when the sperm or egg are formed. The vaccines may act as the trigger, but if no vaccine was given then something else would have triggered the same problems. People with this condition triggered by vaccines are no worse than those with other triggers.

It’s easy to see how parents would associate the two – the onset of illness and the vaccine. And there’s some truth here – the vaccine causes fever and the fever triggers the onset of seizures. But the child already has Dravet syndrome before the vaccine is given, and the seizures, learning difficulties and developmental delay are all inevitable whether the vaccine is given or not.

Children fall ill all the time, and sometimes this will coincide with a vaccine. If you want to know if the vaccine caused the illness, you need to study people who weren’t vaccinated as a comparison.

  1. It’s difficult to study risks from vaccines, especially in young children.

If I wanted to design a perfect study into vaccine safety, here’s how I would do it. I would take a very large population of children, say two million children. I would split them randomly into two groups. One million would get the vaccine, the other million would get a placebo injection. Nobody would know which was which (not the child, the parent or the doctors looking after the children), but this information would be kept in a sealed envelope. Then I would watch and see what happened. I could check autism rates in each group. I could study death rates in both groups. I could study measles rates in both groups, etc etc. Finally, once all the complications were recorded, perhaps a year or two later, I would open the “sealed envelope” to reveal which was which. This is called a randomised controlled double blind trial. Randomised because the children are assigned randomly to each group. Controlled, because I am comparing vaccinated people with unvaccinated “control” subjects. Double blind, because the patients and the doctors looking after the patients are both “blind” to the nature of the injection given.

But here is the problem. We already think we know that vaccinations are good for children. It’s pretty likely that more children would die in the unvaccinated group, and that is not ethical. No-one would sign their children up for a study like this. Even people who hate vaccines wouldn’t sign up, as they might be in the vaccinated group! In fact, no-one in their right mind would suggest this trial, since the net result would probably be extra child deaths, compared to if we just gave all the children the real vaccine.

So how can we ethically test the risks and benefits of doing something like vaccination, which we’re already pretty sure is a good thing? We have to make do with a second best technique, which is to study a child’s health for a period before the vaccine and compare that to the period after the vaccine. Everyone still gets vaccinated, but we study them when they are unvaccinated and compare that to when they are vaccinated. But in a 12 month old child the risk of health problems changes pretty fast, so this isn’t a great comparison. For example, autism tends to develop after 12 months, irrespective of vaccination.

Also, think about the people with Dravet’s syndrome. They are likely to have fever after vaccination, which can trigger seizures in these people. My unethical study would follow them, unvaccinated, for a year, in which time they would have fever from another cause and seizure onset. But the modified approach might conclude that the vaccine caused the seizures.

There isn’t a perfect answer here.

  1. Not getting vaccinated isn’t the same as getting measles

There’s pretty convincing evidence that having measles is riskier than having the MMR vaccine. But that isn’t necessarily the choice parents face. After all, not having the MMR doesn’t guarantee getting measles. If you live in a country with high vaccination rates (and don’t plan to travel) then you’re quite unlikely to be exposed to the virus. This is “herd immunity” again. We rely on this to protect those who can’t have the vaccine, but it can also protect those who choose not to. As long as 95% people do…

So, applying game theory to the problem, I could argue that the least risky outcome for my child is to ensure that all the other children are vaccinated and not to vaccinate mine. Then my child shouldn’t get measles but there’s no risk of side effects from the vaccine either.

Of course, the problem is that the more people who act in this way the weaker herd immunity becomes, and the less everyone is protected. So in a way, if the anti-vaccination campaigners succeed, they will end up putting their own unvaccinated children at increased risk. Currently they can point to the lack of measles related deaths in countries like the US as evidence that the vaccine is not needed. In fact, it’s evidence that it works, even for the people who don’t currently have it.

  1. Vaccines contain “nasty” chemicals

Yes they do.

The purpose of a vaccine is to stimulate an immune response. If you inject someone with a dead virus alone, or a component of a virus alone, the immune system doesn’t really notice. You need chemicals, called “adjuvants” to persuade the immune system to notice and produce the antibodies we need to protect ourselves against infection.

MMR vaccines are “live” vaccines – they use milder living viruses. This allows the immune system to be activated in a more realistic way, and usually leads to higher immunity, without so many “chemicals” being involved.

So almost all vaccines do contain chemicals designed to stimulate an immune response. We’re pretty sure these chemicals don’t have any ill effects, but we can’t be certain.

  1. The people who are harmed are not the people refusing the vaccines.

Yes, the people who are put at risk by the rejection of vaccination are not the people who are refusing the vaccine. It is their children, too young to make their own decision. It is their neighbours’ infants, too young to have the vaccine. It is their relatives having chemotherapy, with an immune system that is in pieces.

Every now and again, a story hits the news about parents refusing medical treatment on behalf of their children. These cases often end up in court, with a judge ruling on the child’s best interest. The parent’s right to refuse treatment on behalf of their child only goes so far. And few would argue that a Jehovah’s Witness should be allowed to refuse a blood transfusion for their child, while he bleeds to death. Vaccination is not quite so black and white, but for some it is in the same ballpark. And the bleeding Jehovah’s Witness doesn’t risk anyone else’s health by refusing treatment.

  1. Health care workers find this debate very irritating!

The evidence for vaccination is not perfect, as outlined above, but it is very very good. We have data on millions and millions of people who have been vaccinated, and we know that side effects are extremely rare, and immunity rates are extremely good. That’s about as good as it gets in healthcare. Most of us practise medicine on a day to day basis with much less evidence than this, and with interventions that have a much lower chance of working.

Measles vaccination is a simple intervention. It is cheap. It helps the person vaccinated, but also contributes to other peoples’ health by the process of herd immunity. It protects the children who are vaccinated, the newborns who have not been vaccinated, the sick. But still, we can’t persuade everyone that it is a good thing.

Some doctors get angry about this. But others would argue that it shows we don’t do a good job of selling vaccination. People ought to be queueing up to get their children vaccinated.

The last words should be left to Roald Dahl, the famous author. His daughter died of measles, showing that being rich and famous wasn’t, and still isn’t, a protection from a disease that has no treatment. At least prevention is now available.

http://roalddahl.com/roald-dahl/timeline/1960s/november-1962

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