Developing the first smallpox vaccine

21 May 2019

Interview with 

Mary Brazelton, University of Cambridge

COW-NOSE

A fresian cow

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We’re jumping back into the past as we look at the history of vaccines. Smallpox was a disease that killed up to 300 million people in the 20th century. Humans eradicated it, meaning it’s not present on the planet outside specialist labs, in 1977. To find out more about how we got to a smallpox free world, Ruby Osborn took a field trip into a herd of cows with Mary Brazleton from the Department of History and Philosophy of Science in Cambridge, to learn how Edward Jenner came up with the first vaccine.

Ruby - We're currently stood in a field with some cows and the reason that we've come to visit some cows is because they were very important in the development of one of the first vaccines.

Mary - That takes us back to the year 1796 and the Gloucestershire physician, Edward Jenner; he was actually a country surgeon. People who worked with cows on a regular basis often didn't get smallpox; they would often get cowpox, which is a virus that we now know is part of the pox family of viruses, closely related to smallpox, that affects cows and that can be transmitted to people when they handle cows quite closely.

Jenner conducted a very particular experiment which is to take an eight year old boy by the name of Phipps and introduce cowpox to him through a process that eventually came to be known as vaccination. That is coming from the Latin word for cowlike - vacca. It's a relatively violent process in so far as you're actually taking a lancet and you're making cuts in the arm or in another part of the body and then introducing material from cowpox pustules into the body.

Ruby - And that's the first introduction of cowpox into the boy was done on 14 May, and that's the same date that we are recording this next to these cows.

Mary - And then Jenner introduced smallpox to the boy, exposed him to smallpox, and he didn't get sick. Slowly over time, it is recognised that using cowpox virus is something that can produce resistance to smallpox. It is also worth noting that there was this older practice of variolation and was actually quite an old practice that had been traditionally done in places like the Middle East and China. Variolation or inoculation is different from vaccination because when you're protecting somebody against a disease by introducing them to a small amount of the disease itself. Part of the thought was that if you're getting exposed to these things early in life, that's going to give you protection. So the concept of, and some of the practices, of vaccination that Jenner was using weren't necessarily so totally new and strange.

Ruby - How quickly did the smallpox vaccination catch on? Were people quite accepting of it or was there any resistance?

Mary - Well, there were reports of resistance really that developed quite quickly. Clerical opposition, religious opposition to the notion that by inducing resistance to a disease you could somehow be subverting divine will. There are concerns about the bastial nature of the process in which you are taking material from an animal originally and introducing it often to the body's of infants. New questions arise of individual rights and the ways in which individual freedoms might be restricted by larger social mandates to vaccinate for the public good. And some concerns are simply that it will hurt, that it will cause some kind of local reaction or inflammation.

Ruby - The smallpox vaccine came about really just because of an observation, how did we transition from that to actively trying to develop vaccines to specific diseases?

Mary - That generalisation, a moving from a vaccine for one particular disease - smallpox, to the concept of a vaccine as an intervention that will induce immunity against a particular illness, that is something that we see very much coming out of a much later period; particularly the late 19th century development of things like bacteriology and the germ theory, and so for that we have to think about really another generation of researchers. People like Louis Pasteur, Robert Cook, and the ways in which they really do several things in rapid succession. They identify a particular microbiological agents of disease and, moreover, they seek to develop interventions to develop resistance. So when Pasteur develops a means of making livestock resistant to things like anthrax in the 1880s, he calls that intervention of vaccination in honour of Jenner and so that's really when we see vaccination emerge as a general term for a variety of immunological interventions. Even though many of what we think of now as the fundamental parts of immunology, the fundamental theories and understandings, those come even later. The smallpox virus isn't really even isolated and identified clearly as such until the 1930s with the advent of electron microscopy because viruses are so small. So all of the work that's done on smallpox vaccination before that is down to empirical work in many ways, which is fascinating, I think.

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