Defeated disease – smallpox and polio

The deadly disease Ebola is currently hitting the headlines and scientists are desperately battling to find a cure. They can take comfort from the fact that many other virulent diseases have now been completely eradicated or virtually defeated, including smallpox and polio.


Smallpox was an extremely contagious viral disease which had a mortality rate of around a third of infected patients. Symptoms included a red, raised rash that turned into large blisters and survivors often suffered blindness and scarring. The earliest records of the illness date back to the time of the Egyptian Pharaohs and it contributed to the fall of the Aztec and Incan empires and the destruction of many of the North American Indian and Australian Aborigine tribes. Variolation, a treatment that inoculated a healthy person with tiny amounts of smallpox, could give immunity to the disease but often led to infection and it was not until the British doctor, Edward Jenner, hit upon the idea of inoculating with cowpox that a safe vaccination was found in 1796. It took several centuries for the world’s population to be vaccinated, but in 1979 the global eradication of smallpox was formally declared.


Polio is a viral disease that mainly affects young children. It attacks the central nervous system, causing pain, stiffness, fever and vomiting, and can lead to permanent paralysis. The disease has no cure and can only be prevented by infant vaccination, which needs to be done multiple times for each child. While polio has been reduced by nearly 100 per cent since 1988, it is not totally eradicated and still remains in three countries: Pakistan, Afghanistan and Nigeria.