Edward Jenner

"Eduard Jenner" by Vigneron Pierre Roch (1789-1872)

“Eduard Jenner” by Vigneron Pierre Roch (1789-1872)

You will probably be aware of news items surrounding vaccinations – most likely the MMR controversy initiated by Andrew Wakefield in 1998. This issue resurfaced in 2013 when there was a measles outbreak in Wales, after some parents decided not to vaccinate their children.

But how do vaccines work? And who started it all off? I’ll answer the second question first.

Edward Jenner was a West Country lad through and through. Born in 1749 in Berkeley, Gloucestershire, he was schooled in Wotton-under-Edge and Cirencester – before learning his medical trade as an apprentice in Chipping Sodbury. He did leave for London (to complete his qualifications) in his early twenties, but returned to work in his native Gloucestershire two years later.

At the time, one of the most dangerous diseases was smallpox – and the only way of preventing it was something called ‘variolation’, or ‘inoculation’. This involved taking samples (sometimes of scabs or pus – ew!) from patients and rubbing into cuts made in the skin. The patient developed a diluted form of the disease and is then immune to smallpox. Variolation (derived from the Latin name for smallpox, ‘Variola’) was actually quite a risky procedure, which led Jenner to experiment with a folk tale that cowpox sufferers never caught smallpox. Cowpox is basically the cow version of smallpox, but a lot milder – and it can be transferred to humans. He tested his hypothesis in 1796 on a local boy, using a sample from a cowpox-infected milkmaid. Once cowpox symptoms had passed, Jenner used variolation to test the boy’s immunity. Thankfully he had been successful!

“Essentially beneficial to mankind”

And as for how they work… Basically, the aim of the vaccine is to create an immune response – that way, when the patient is exposed to the ‘real’ disease the ‘real’ immune response can kick in a lot quicker, stopping the infection in its tracks. This is why you might feel like you’ve come down with a cold following your ‘flu jab – it’s your white blood cells identifying things called ‘antigens’ (kinds of markers on cell surfaces) and leaping into action. In the first phase, ‘macrophages’ digest all but the antigens, which are then recognised by ‘lymphocytes’. (Macrophages and lymphocytes are broad categories of white blood cells.) The latter mop up any remaining infectious cells and lay the groundwork for future disease prevention.

But Jenner didn’t just work on immunology. He did other medical research, such as post-mortem examinations on angina victims; Jenner made the link between fatty deposits lining their arteries and the disease that killed them. For variety, Jenner also studied how cuckoos parasitise other birds’ nests; hibernation and bird migration. He was a lifelong collector of fossils.

Edward Jenner remained in Gloucestershire for much of his life, dying of a stroke in 1823. He left behind a legacy that we all take for granted.


This article was written as part of the ‘Biology: Changing the World‘ project for the Society of Biology, but heavily edited and not accredited.

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