Edward Jenner usually gets the credit as the world’s first vaccinator but arguably the title should belong to North Dorset’s own Benjamin Jesty.

Almost 250 years before covid vaccines hit the surgeries and 22 years before Jenner did his thing, Yetminster’s Jesty performed an extraordinary medical experiment on his own family.

As a farmer, Jesty knew of the country belief that people who’d had contact with cows that had cowpox were immune to the virus’s more serious cousin smallpox.

Smallpox was a ghastly disease that usually led to facial scarring and often death.

But people with cowpox escaped with a mild fever and lesions on the hands at the point where the virus entered the skin.

Dairymaids were known for their fair complexions in contrast to smallpox survivors, and Jesty had first-hand evidence of this.

His own dairymaids, Anne Notley and Mary Reade, had both been infected with cowpox by contact with the udders of cows they had milked yet both escaped smallpox even when nursing relatives with the disease.

When a smallpox epidemic broke out in North Dorset in 1774, Jesty made what his biographer Patrick J Pead describes as a ‘quantum leap’ in thinking.

‘Faced with the awful implications of his family suffering the ravages of smallpox, and knowing the hazards of inoculation, he conceived an ingenious idea,’ writes Pead.

Inoculation had been practised for several decades but involved introducing one of the actual smallpox viruses.

Although it saved some lives, it claimed others due to a lack of control over the type of virus used.

Jesty’s ‘quantum leap’ was to borrow the inoculation method but replace the smallpox virus with cowpox.

Displaying amazing confidence in his plan, he took his family to Chetnole, where William Elford had some cows with the marks of cowpox on their udders.

Jesty then used a stocking needle to take a tiny sample of pus from an udder and insert it into the arm of his wife, Elizabeth.

He then repeated the procedure with sons Robert and Benjamin, then aged three and two respectively, but omitted baby Betty.

Jesty’s effort may never have become known had it not been for a complication that arose.

While the infants suffered no significant ill effects, Longburton farmer’s daughter Elizabeth developed a fever and was treated by the slightly disapproving Dr Trowbridge of Cerne Abbas.

She recovered fully and none of the trio ever succumbed to smallpox despite the boys being inoculated with it by Dr Trowbridge in 1789.

Jesty tried to keep a low profile but word soon got around and he his fellow villagers proved seriously unsympathetic.

Suspicious of anything that did not conform to their existing beliefs and familiar with biblical warnings against contaminating the body with animal matter, people subjected Jesty to physical and verbal abuse.

Despite this, the Jestys continued living in their Yetminster farmhouse, called Upbury, until 1796, when Jesty moved them to Downshay Manor, Harmans Cross, near Swanage, which offered more land and more space for a family that now included seven children.

Coincidentally, 1796 was also the year that Jenner administered his first experimental cowpox vaccination on eight-year-old James Phipps at Berkeley, Gloucestershire.

Because he was a village doctor, Jenner was better placed than Jesty to put the method on the medical map.

He also coined the phrase ‘variolae vaccinae’ – meaning ‘vaccine of the cow’.

This is the origin of the word ‘vaccine’ that we use today.

Jesty, meanwhile, continued vaccinating people in his new parish, where his method was better received than at Yetminster.

There’s a memorial inside Worth Matravers church to someone whose mother was ‘personally inoculated for the cow pox by Benjamin Jesty of Downshay’.

A Swanage clergyman, the Rev Andrew Bell, was so impressed that he campaigned for some recognition for a man ‘so often forgotten by those who have heard of Dr Jenner’.

As a result, in 1805 Jesty was invited to the Vaccine Pock Institution in London, whose members questioned him at length and tested his and son Robert’s continued immunity by inoculating them with live smallpox.

Both proved immune and the Institution praised not only Jesty’s pioneering work but his ‘superior strength of mind’ in the face of ‘prevailing popular prejudices’ and the ‘clamorous reproaches of his neighbours’.

They also presented Jesty with a testimonial scroll, a pair of gold-mounted lancets, 15 guineas to cover his expenses and a portrait by Michael W Sharp, whose other subjects included the Duke of Wellington.

Jenner later acknowledged Jesty’s contribution as ‘corroborative evidence’.

Jesty died in 1816 aged 79. His gravestone at Worth Matravers describes him as the ‘first person (known) that introduced the cowpox by inoculation’.

Elizabeth lived to be 84. Sons Robert and Benjamin died in their sixties in 1839 and 1838 respectively.

• This article was adapted from Roger Guttridge’s book Dorset: Curious and Surprising (Halsgrove, £9.99).