By Grant Jacobs 19/02/2019

Vaccine-preventable disease outbreaks are happening everywhere. Measles is on the rise worldwide, including in Europe and the USA. Over 900 have died in Madagascar alone since October 2018.[1] Most will be infants. Japan’s rubella epidemic has prompted traveller warnings. 367 cases have been reported this year. Venezuela has considerable problems, not helped by diphtheria coming back. The list just goes on.

Many outbreaks feature those who’ve chosen not to vaccinate.[2] The WHO has called ‘vaccine hesitancy’ one of their top-ten global health threats.

It’s appalling, really, that it’s come to this.

I feel for parents and parents-to-be facing the claims made by the few who oppose vaccines. We all worry about kid’s safety. Recently I wrote a few suggestions for new parents or parents-to-be facing vaccine opinions. Just out is summary of the evidence for the main vaccine concerns. It might be a useful follow-up. It’s enough to see the essence of the evidence without it being overwhelming. You’ll want to download the PDF file draft copy to read it.

Below I’ve added a few thoughts that might help round the summary out a bit. Don’t forget to read the summary – it’s the main thing!

Why share this summary?

There are heaps of summaries out there. I’m sharing this one because it sits between in-depth science and the lighter summaries on many informational websites.

The summary links to the research literature for those wishing to take it further. In practice you’ll be better to read material from reputable sources that’s written for non-scientists, or ask questions at a forum like ours. There’s a lot background knowledge assumed that’s needed to read the science accurately.

Don’t miss the table of ‘facts’. It’s down at the end after the text of the article. When scientists submit articles, all illustrations and tables are listed separately after the article.

I’ve added a few thoughts to each of the topics the summary covers below.

MMR (measles, mumps, rubella) vaccine and autism

Vaccines do not cause autism. We can state that with some certainty. Over a dozen large epidemiological studies rule out an association of vaccines and autism. More practically autism starts in utero, before the child is born, and autism is dominantly genetic.

That this myth is persisting is awful.

This fuss started from uncritical media accounts of claims made by Andrew Wakefield. In a press conference he suggested a connection between the MMR vaccine and autism. There never was good evidence for this claim. Since then his research has been exposed as fraudulent. Like all good court-room dramas the full story is long with many twists! Siouxsie Wiles has a nice short coverage of the ‘Wakefield’ story. These days he is the centre of a circus that raises money for himself and the anti-vaccine ‘movies’ he stars in. Think (fake, niche) celebrity with ‘odd’ ideas.

It’s worth adding that It’s not just measles that’s a problem, but also illnesses after having had measles. Measles causes a kind of immune system amnesia. It kills off T-cells, a part of our immune systems that organises response to infections. They’re part of the ‘memory’ we keep of things our immune system ought to respond to. The upshot is that for up to several years after a measles infection kids are susceptible to illness they’d normally fight off.

Thimerosal (incorrectly ‘the mercury’)

Thimerosal doesn’t accumulate in the body, and doesn’t cause autism either.

It’s not in childhood vaccines. To avoid a drop in vaccination over unwarranted ‘concerns’, thimerosal was removed from childhood vaccinations many years ago. One easy way to realise it doesn’t cause autism is that autism rates didn’t drop when thimerosal was removed.

It’s often incorrectly talked about as ‘the mercury’ in vaccines. This is confusing different chemicals. Thimerosal is not metallic mercury, which is infamous for ill effects. Thimerosal is an organic compound that tightly binds the mercury ion it contains, and passes through our bodies.

Guillain-Barré Syndrome (GBS)

GBS very rare, and influenza—what the vaccine prevents—causes a higher rate of GBS than what might be attributed to the vaccine. Only the flu vaccine has this possible link.

The flu vaccines have a slightly higher risk of GBS compared to the baseline risk of the population-at-large, but a lower risk of GBS than those catch the flu. The overall effect is that vaccination can decrease the overall GBS risk by preventing influenza. Hey, no-one said science was easy!

There is a small possible risk, but you have to step back and see the whole picture.


There is no evidence suggesting this is happening.[3]

Safety of HPV vaccine

I’d suggest readers try Helen Petousis-Harris’ blog Diplomatic Immunity for the HPV vaccine. Her blog covers the HPV vaccine at some depth. Or just search the Sciblogs home page for ‘HPV vaccine’. Long story, short: there is a lot of safety tests already done, and the vaccine looks fine.


This one has been covered on Diplomatic Immunity and bioblog. It’s a bit of a doozy: infants (and us) get aluminium every day in our diets. The amounts in vaccines are well below toxic levels. (Why do people think that scientists and doctors are going to inject toxic amounts of something?)

Like the case for thimerosal, there is some confusion over basic chemistry. Aluminium is not a heavy metal. Our bodies normally contain some elements that are technically metals. Examples are sodium (part of table salt), zinc, calcium, iron, copper and others.

The aluminium salts are added because they alert the immune system that something needs attention (‘hey, over here’), making the vaccine more effective.

Too many too soon

Kids get exposed to a vast number of new things that are not part of their bodies every day – far more than what is in all the vaccines they will ever receive. In any event, this one has been tested too. Risk of disease or developmental disorders doesn’t increase with the number of vaccines. One of the studies is covered in Are too many vaccines too soon harmful?

The companies

This isn’t in the summary I linked to, but I’m adding it. For vaccines the key control decisions lie with public health institutions. Not ‘the companies’. (Besides, we all complain about large companies. I have some bones to pick with a few NZ telcos…)

Last thoughts

The diseases are out there. If you don’t vaccinate, you’re vulnerable.

Contagious diseases like measles are good at ‘finding’ those who are vulnerable. Herd immunity for something like measles only works if vaccination levels are very high. Drop below the threshold, and the disease can make the rounds.

The outbreaks in the USA, for example, are from travellers bringing it back. Once back, it spreads if local immunity levels are low. It’s the same for NZ.

Public health professionals can’t help you if you don’t help yourself!

Other articles on Code for life


  1. I’d like to delve into further into what is happening in Madagascar as it’s a country I’d like to visit one day. (I still regret missing an opportunity a couple of years ago to fly to Mauritius from Sri Lanka for the proverbial song.) I can’t find a text statement of the 922 deaths, there appears to only be the MP3 of a press conference. The measles vaccination rate is just 58% – far below the ~95% needed to provide herd immunity. With that in mind this will only get worse. These figures will underreport the real number of cases.
  2. Venezuela is a likely exception. Their economic and political problems have spilled over to public health problems. Neighbouring countries are reported as trying to prevent disease coming from Venezuela.
  3. My guess is that this concern comes largely from people with chronic illnesses desperately wanting a ‘cause’ for their illness. It’s very understandable, but it’s not helpful to ‘finger’ something without evidence.


Principal Controversies in Vaccine Safety in the United States
Frank DeStefano, MD, MPH; Heather Monk Bodenstab, PharmD; Paul A Offit, MD

Clinical Infectious Diseases, ciz135


Published: 12 February 2019

About the featured image


Marciana’s four-year-old son receives a UK-funded measles vaccination carried out by Save the Children in the Tanauan municipality of Leyte, Philippines. The programme aimed to vaccinate every child in their community in one day, to help prevent outbreaks of the disease in the aftermath of Typhoon Haiyan.
“Our house was flooded by the sea during the typhoon and collapsed”, says Marciana.
“It was a very difficult time for my family. I’m glad my boy has had his vaccinations as I know he is now safe from disease.”

Source: Wikipedia. CCA-2.0, generic.

0 Responses to “A summary of the evidence for the main vaccine concerns”

  • Grant, the WHO hasn’t called ‘vaccine hesitancy’ one of their top-ten global health threats.

    They say, “Here are 10 of the many issues that will demand attention from WHO and health partners in 2019.”

    …”10 of the MANY issues that will demand attention from WHO”

    WHO define Vaccine Hesitancy as:
    Definition: Vaccine Hesitancy
    Vaccine hesitancy refers to delay in acceptance or refusal of vaccines despite availability of
    vaccination services. Vaccine hesitancy is complex and context specific, varying across time, place
    and vaccines. It is influenced by factors such as complacency, convenience and confidence.

    See Figure 1: The Continuum of Vaccine Hesitancy between Full Acceptance and Outright Refusal of all Vaccines in WHO link.

    And view decision making re vaccine uptake along a continuum

  • Rob,

    Whilst I accept your comment about the WHO report on global health threats, I give much more credence to Grant’s interpretation that these are the top-ten global health threats.

    After all, why would the WHO go to the trouble of writing a report on the lowest ten global health threats, or even ten middling global health threats, rather than the top ten?

  • “Too many too soon” might well be harmful, but that’s why the schedule is set as it is. It’s “the right amount at the most appropriate time”, and based on evidence.

  • Hi everyone,

    I would strongly prefer this space be kept for new parents & parents-to-be to ask questions, not nitpicks please.

    Pointing at “top 10” or not deflects from the topic of the post (evidence for the main vaccine concerns), and misses the main point of that passing mention: it’s clearly a serious concern they’ve identified and included it in the ten they felt were worth highlighting. Current events show they’re justified, too.

    Madeleine (maybe there’s a typo that has introduced a grammatical error? I’m struggling to read your intended meaning): We could give many more antigens safely (and previously did*). Common illnesses routinely do. The WHO has a short page explaining this concern – (The other 5 concerns are worth reading too.)

    This article gives more background on this area on this for those who like reading. It’s more than parents really need, but you want to dig in go for it:

    There are practical benefits to trying to have fewer visits to doctors by offering vaccines covering several diseases at once. I’d like to think most parents would appreciate few trips to the GP or nurse!

    (* Some previous vaccines had more antigens than today c.f. the older DPT vaccine and the smallpox vaccine. Antigens are the things the immune system is responding to – the proteins or complex sugars on the surface of the viruses and bacteria that cause an illness or are in the vaccine. The idea of vaccines is to present these to your body, so it can prepare a ‘ready-to-roll’ defence the next time it encounters these. It’s the count of antigens in the vaccines that matters, not the number of vaccines.)

  • I just meant that it’s an unfounded concern. There current schedule is far below being ‘too many’ vaccines, and they’re given at times that balance between being old enough to the right kind of immune response, young enough that the vaccine predates possible exposure to the disease, and so protection is there during times of greatest vulnerability.