Target Zero Day, when smallpox was finally declared eradicated

It was a red-letter day in the history of medicine – ‘Target Zero Day’, 8 May 1980, signified the complete eradication of smallpox, a terrifying scourge that had previously killed one in 12 worldwide. Smallpox was untreatable but, luckily, it turned out that vaccination provided good protection – and that intensive immunisation could exterminate the smallpox virus by blocking its spread.

According to legend, vaccination was invented by Dr Edward Jenner of Berkeley, Gloucestershire. Jenner showed that healthy children inoculated with cowpox, a mild infection of cattle, could not catch smallpox. He was supposedly inspired by a comment from a local milkmaid, but there is evidence the idea came from a medical friend, John Fewster, who had experimented with cowpox. Vaccination goes back even further. In 1774, a Dorset farmer, Benjamin Jesty, inoculated his wife and sons with cowpox; Jesty’s experiments were belatedly publicised in 1803, by doctors trying to undermine Jenner’s reputation. Nonetheless, Jenner deserves credit for catapulting vaccination into the medical mainstream with his Inquiry into the Causes and Effects of the Variolae Vaccinae, or Cow-Pox, published in 1798.

In 1966, 160 years after the prophecy

The heroic 11-year that vaccination would exterminate the

drive to destroy the disease, the World Health Organization launched its Smallpox Eradication

disease was a triumph Programme. This heroic 11-year drive was masterminded by two American

of preventative public health doctors, DA Henderson and Bill Foege. Their adversaries included

medicine both geopolitical barriers, and colleagues at the WHO who wanted the smallpox budget. One WHO apparatchik even Dr DA Henderson examines children’s promised to eat a tyre if smallpox was smallpox vaccination scars in Ethiopia eradicated; Henderson duly promised to send him the tyre and wished him bon appétit. But Henderson and Foege’s hard work paid off – three years after the last smallpox case was notified (to make sure no outbreaks had been missed) Target Zero Day was declared.

So 40 years on, why should we remember Target Zero Day? First, to celebrate a triumph of preventative medicine and freedom from a brutal disease. We must also remember the victims of smallpox. In 1914, a Canadian professor warned against forgetting smallpox, which was fast disappearing from North America. It went on to kill at least another 250 million people – three times more than both world wars combined.

Target Zero Day also reminds us of unconquered infections, including polio, measles, malaria, and of course the coronavirus Gareth Williams Covid-19. As I write, the WHO has upgraded is emeritus professor Covid-19 to a pandemic, the NHS is on a war and former dean of footing and stock markets are wobbling. So far, medicine at the though, the virus’s impact is modest compared University of Bristol, and the with smallpox. So let’s recognise Target Zero Day author of Angel of Death: The for what it is: a milestone in world history and a Story of Smallpox (Palgrave monument to the art of the possible. Macmillan, 2010)