History of Vaccination

00:00 It’s sometimes quite hard to look back in history and find the origins of particular medical procedures.

00:08 But there is evidence for the ancient Chinese practice of variolation using dried smallpox scabs blown into the nose.

00:20 This produced a milder form of the disease.

00:24 It was not without risks.

00:26 Around about 1-2% of variolated individuals died.

00:32 However this compares with approximately 30% who died following natural infection.

00:38 These individuals were subsequently protected from smallpox.

00:45 By 1700, variolation had been adopted in India, the Ottoman Empire and Africa.

00:56 Edward Jenner noted in England that dairymaids infected with cowpox became immune to smallpox.

01:06 In 1796 he deliberately infected a boy, James Phipps, with cowpox through scratches in the skin.

01:16 Subsequently he exposed the boy to smallpox.

01:20 Clearly with today’s ethics committees, there is no way this experiment could be done.

01:26 But in those days he was able to do this.

01:29 And I’m sure he was incredibly relieved to find that the boy was actually protected.

01:36 Jenner published his findings in 1798, concluding that vaccination provided immunity to smallpox.

01:44 And this really laid the foundations of modern day vaccinology as we know it.

01:54 So what’s required for a successful vaccine? Of course it needs to be effective, it needs to work.

02:02 It needs to elicit an appropriate adaptive immune response, that will depend upon the particular pathogen.

02:09 Are antibodies required to defeat the pathogen or are cytotoxic T-lymphocytes required? Or maybe both? The vaccine needs to be stable, needs to be affordable.

02:21 So it needs to be relatively inexpensive.

02:24 And of course it has to be safe.

02:30 There are two infectious diseases that have been completely eradicated from the world following global vaccination campaigns. Smallpox was eradicated from humans in the year 1979. Rinderpest which does not affect humans but is a important disease of cattle, economically very important, was eliminated in the year 2011. These are the only two infectious diseases that so far have been eliminated by vaccination but they show that it is possible to eliminate infectious disease using these procedures. Polio could well be the next disease that is eliminated following vaccination. Here you can see the notifications of paralytic polio in the United Kingdom. And you can see that following the introduction of vaccination in the mid 1950s, initially with the inactivated polio vaccine IPV.

03:40 And then a little bit later, the oral polio vaccine which is a live vaccine; that by the mid 1960s, polio was essentially eliminated from the United Kingdom.

03:54 Polio has been eliminated from the vast majority of the globe.

04:03 In fact, it’s only currently endemic in Afghanistan and Pakistan.

04:08 That doesn’t mean that it couldn’t potentially reestablish itself in other countries.

04:13 But at the moment, there’s just a very small area of the world where polio is still endemic.

04:18 And of course the hope is that in the very near future, it will be completely eliminated and join smallpox and Rinderpest as being a disease that has been eliminated by a vaccination.