measles infection is not a cure for cancer

I never thought I’d need to write that title for a post.

We’re continuing to hear of new measles cases in New Zealand, most recently in this Stuff story about 4 new cases in Auckland (with the possibility that up to 1600 people may have been exposed). One of those ill with the disease is a 10-month-old child, too young to have received her first dose of the MMR vaccine.

Completely predictably, the usual anti-vax enthusiasts are there, claiming (as usual) that measles is a benign childhood disease (it’s not); that measles infection strengthens your immune system (the reverse is true: it causes a sort of ‘immune amnesia’ for the next 2-3 years, carrying with it an increased risk of illness & death from other diseases); and that more people are seriously harmed from vaccination than by the disease (without actually providing any evidence in support).

Oh yes, and effectively writing off all the children dying in developing countries; somehow we need only be concerned with ourselves. Case in point:

Rather than dissect the whole (pretty awful) comment, I thought I’d focus on that claim about measles providing immunity against cancer, as it’s one I’ve seen made a few times now. So, can measles cure cancer, or provide immunity to it?

The claim seems to be based on reports in 2014 from a trial of an oncolytic viral therapy, involving just two people, both seriously ill with a form of blood cancer. And the experimental treatment did involve measles virus. BUT – and this is a very big ‘but’ indeed – we are not talking wildtype measles. What follows is a synopsis of the main points in an excellent post by Cancer Research UK.

The trial used an attenuated measles virus – ie one that couldn’t actually cause the disease. Straight away, we are not talking the equivalent of wild measles infection.

The attenuated virus was also genetically modified in a way that allowed the researchers to see which cells it had infected.

The trial infused each patient with huge amounts of the attenuated, modified virus – 100 billion units (enough, apparently, to vaccinate around 10 million people). Over a period of just one hour. Natural infection is not going to do this.

The virus particles infected bone marrow cells, and triggered a rapid, large, immune system response. Initially both patients’ tumours shrank, as did the titres of cancerous cells in their blood. Only one appears to have achieved lasting remission, and the lead researcher has said that the Mayo Clinic hasn’t been able to reproduce this outcome. There’s an interesting article about the patient’s progress, and the state of play regarding the Mayo Clinic’s ongoing research into oncolytic viral therapy, at this link.

This is a fascinating area of research, but it’s clear that at the moment apparent successes in curing mice haven’t translated to the same outcome in human clinical trials. (It’s also worth noting that this lack of successful translation is relatively common.)

But what boggles the mind is that anti-vaccination activists plague enthusiasts can so readily promote incorrect claims – in this case, that having measles protects against cancer – when the actual evidence is so clearly against them.

Image by Teseum, on Flickr.

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