Thread by @GidMK

This is a common claim by anti-vaccine advocates, but it's worth unpicking the actual risks and rewards behind vaccination #vaccineswork 1/

https://twitter.com/NancyBarto/status/1100175588688519169

Do vaccinations carry risks?

Yes, absolutely. No medical intervention is entirely without risk

So what does that risk look like? 2/

Let's look at the MMR vaccine, because it is one of the most hotly-debated and also well-researched vaccines out there 3/

If we look at the gold standard of evidence for MMR - a large Cochrane systematic review - we can see identified risks:

- increased risk of febrile seizures immediately post-vaccine
- possible increased risk of febrile convulsions 4/

Review is here if you'd like to read: ncbi.nlm.nih.gov/pubmed/22336803

Another review here as well: pediatrics.aappublications.org/content/134/2/… 4.5/

We can ALSO see the things that so far have never been shown to be associated with MMR vaccination:

- autism
- asthma
- leukaemia
- have fever
- diabetes
- gait disturbance
- Crohn's
- demyelinating diseases
- other bacterial/viral infections 5/

Added to this, we can see the BENEFITS of the MMR vaccine:

- >95% effective in preventing measles
- >95% effective in preventing rubella
- >80%% effective in preventing mumps 6/

So now we have to weigh up the risks vs the benefits

This is where the "risk/choice" argument comes in 7/

The risks associated with the vaccine may sound scary, but they are actually incredibly small. For every million kids vaccinated we'll see about:

1,000 febrile seizures
50 hospitalizations
0 deaths 8/

On the other hand, measles, mumps, and rubella are really infectious disease. They also have serious harms 9/

For every million kids who get measles, we expect to see:

250,000 hospitalized
1,000 cases of encephalitis
1-2,000 deaths 10/

Mumps and rubella aren't nearly as nasty as measles, but in a million cases we'd expect to still see dozens of deaths, hundreds of lifelong disabilities, and thousands of hospitalizations 11/

This is where we weigh the risk and benefit of vaccination. In an unvaccinated population, pretty much every child will get measles. Most of them will get mumps and rubella as well 12/

So the risk from the MMR vaccine for serious issues requiring hospitalization is about 50/1,000,000 = 0.005%

The risk of serious issues just from measeles is about 250,000/1,000,000 = 25% 13/

In other words, a child is ~5,000 times more likely to go to hospital because of measles than the MMR vaccine 14/

This isn't even including mumps and rubella! They are nasty diseases that also land plenty of kids in hospitals 15/

What does this mean about "choice"?

Well, there are obviously risks to vaccinating. But these are FAR outweighed by the risks of NOT vaccinating 16/

It's a bit like saying we shouldn't give seatbelts to children because they cause chafing

The language of "choice" and "risks" in context simply doesn't make sense 17/

We vaccinate because it is the best option, far better than letting children - and adults! - suffer and die #VaccinesWork 18/end

P.S. current best evidence strongly indicates that MMR vaccination is not associated with autism or any of the other conditions above. This has been shown time and again