The vaccine for smallpox was developed by:

Edward Jenner (1749-1823) was an English doctor from Berkeley, Gloucestershire. He is called the "Father of Immunology" for developing the world's first vaccine, against smallpox.

Smallpox was a highly contagious and deadly disease caused by the variola virus. It caused fever and a rash of fluid-filled blisters, killed about 30% of those infected and left many survivors scarred or blind. For centuries, it was one of the most feared diseases in the world.

Jenner noticed a common belief among country people that milkmaids who had caught cowpox, a mild disease of cows, did not get smallpox. On 14 May 1796, he took material from a cowpox blister on the hand of a milkmaid named Sarah Nelmes and inoculated it into the arm of an eight-year-old boy, James Phipps. The boy developed a mild fever. Later, Jenner exposed him to smallpox material, and the boy did not get the disease. Jenner published his results in 1798.

The word "vaccine" comes from the Latin word vacca, meaning "cow", and vaccinia, meaning cowpox. Later, Louis Pasteur extended the term "vaccination" to all such preventive inoculations in honour of Jenner.

Smallpox vaccination spread across the world. In 1967, the World Health Organization (WHO) launched an intensified global smallpox eradication programme. The last natural case occurred in Somalia in 1977. On 8 May 1980, the WHO declared smallpox eradicated. It is the first and so far the only human disease to be completely eradicated. India was declared free of smallpox in 1977.

Why not the other options?

• ✗Louis Pasteur developed vaccines for rabies (1885) and anthrax, and the process of pasteurisation.
• ✗Robert Koch discovered the bacteria that cause tuberculosis (1882) and cholera.
• ✗Jonas Salk developed the first injectable polio vaccine (1955); Albert Sabin developed the oral polio vaccine.