Science Corner

The Science Corner: Herd Immunity

The science corner: Herd immunity - graphic of sheep

With the anti-vax movement picking up more steam than it ever deserved to have, kids are being put at risk from serious preventable illness.  Unfortunately, the anti-vaxxers aren’t just putting their own kids at risk, they’re increasing the risk for other kids as well.

Herd immunity refers to the extra protection that comes from vaccinating a threshold percentage of the population.  Let’s say your herd consists of sheep in a pasture.  If you vaccinate enough sheep, then it’s hard for an infectious agent to jump around in your pasture because there are so few bodies it can jump to.  The vaccinated part of the herd then ends up protecting the sickly little lambs and the sheep who weren’t able to get vaccinated.  Enough of the herd is protected that the infectious agent just can’t get to the vulnerable ones.

Getting back to humans, some people can’t get certain vaccines for medical reasons.  That might be due to allergy, but often it’s because people who are immunocompromised (either due to a medical conditional or immunosuppressant drugs) can’t get what are known as “live vaccines”.  These tend to be the same people that are most vulnerable to getting really sick if they’re exposed to an infectious agent.

This is a huge issue when it comes to the MMR (measles mumps rubella) vaccine.  It’s a live vaccine, so immunocompromised people generally can’t get it.  Measles is highly contagious, and that fast and easy spread of infection means that the threshold to achieve herd immunity is also high, at 93-95% (as per the WHO).

That doesn’t leave much room for anti-vaxxers to get in the way before the whole thing starts falling apart.

The World Health Organization reports that in 2017 there were 110,000 measles deaths globally, with most of the deaths in children under 5 years old.  That’s a lot of entirely preventable deaths.

Ideally, almost everyone would be getting vaccinated, and measles, mumps, and rubella would all go the way of the dodo bird, just as smallpox was declared eradicated in 1979.

It’s disturbing that kids’ lives are getting put at risk because of concerns that vaccines cause autism, which study after study has shown not to be the case.  It’s one thing when people want to choose nonsense, but when it puts kids’ lives (both their own and others) at risk that’s not ok.

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17 thoughts on “The Science Corner: Herd Immunity”

  1. Great post. My mother decided all of a sudden that she “doesn’t believe in vaccines”. So she won’t be meeting g Mya Jayn for 3 months 😆

  2. I am so sorry that we need to talk about this but we do. I am vaccinated against everything possible and I have only benefits from it. The curious thing is that we have the science, the knowledge, the means and people ‘prefer’ to listen to someone else who gives them bad advice for their benefit. It’s really sick.

    The parents opposed to vaccines themselves ARE vaccinated! Don’t they remember how many children were crippled and were in pain due to polio BEFORE the vaccine? How scared the parents must have been every summmer because the apple of their heart could become sick due to an unknown disease? Children were put in an iron lung. And now? They are ‘against?’
    Utter bs! I will vaccinate everything: my baby, myself and my dog and the goldfish if needed. I mean, those anti-vaxxers don’t they go on a holiday? Don’t they get a vaccine against let’s say yellow fever? Malaria? It’s crazy and will lead to the survival of the fittest with and that is so very sad people who will die because they can’t be vaccinated. And one more thing: what’s the crusade against autism? What’s wrong with having autism? I think they are being very hurtful against people who must live day in and day out with – in their – eyes a ‘preventable’ disease, which it is NOT!
    * their, they = anti-vaxxers

    Great post though!

  3. It’s weird that there have been hundreds of studies of man-made climate change and still people don’t believe it, but just one disputed study has turned so many people against vaccination.

    Mind you, everyone accepts that smoking is dangerous and still loads of people smoke so maybe people are just not logical?

  4. The anti-vaxxers just make my blood boil! Perhaps we should call them what they really are – murderers. I get incoherent on this subject, it makes me so angry. I was born in 1946 and there was no vaccine, when I contracted measles I almost died from it. So I have NO patience for these anti-vaccine people – NONE!

  5. There’s a fascinating study looking at people who believe in conspiracy theories and how it gives them a sense of control and order. It also talks about their pathology of being lied to by people they deemed in positions of power when they were young. It’s actually quite fascinating, and anti-vaxxers, to me, are just a grassy knoll away from being conspiracy theorists.

  6. I am so impressed by your commitment to debunk pseudo-science! Anti-vaxxers absolutely make my blood boil. And the whole “vaccines cause autism” argument has always puzzled me. Even if vaccines DID cause autism (which I don’t believe they do) – why would someone prefer lose their kid to a preventable disease than have a child with autism?

  7. Kudos for making this so reasonable and level-headed. Approaching the issue with fury won’t change any minds. Dang, though, the anti-vax trend makes me so mad.

  8. My mom made sure me and my siblings were vaccinated. It benefited us. There is much lies being spread on the internet that people will believe anything if its written believably. Doesn’t autism start developing before a child is born?

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