Smallpox vaccine, the world's first vaccine, was developed by Edward Jenner in 1796 to protect against which disease?

Smallpox vaccine, the world's first vaccine, was developed by Edward Jenner in 1796 to protect against which disease?

• A. Malaria
• B. Polio
• C. Smallpox
• D. Diphtheria

Answer: (C)

The main idea is using a milder, related pathogen to train the immune system to fight a more dangerous one. Jenner observed that people who had cowpox seemed protected against smallpox, a much deadlier disease caused by a different, but related, virus. He used material from cowpox lesions to inoculate a person, who then showed immunity when later exposed to smallpox. This demonstrated that immunity to a related virus could prevent infection by the more dangerous smallpox virus, laying the groundwork for vaccination. So the vaccine was developed to protect against smallpox, not malaria, polio, or diphtheria. The other diseases have their own distinct pathogens and later vaccines were developed specifically for them.

The main idea is using a milder, related pathogen to train the immune system to fight a more dangerous one. Jenner observed that people who had cowpox seemed protected against smallpox, a much deadlier disease caused by a different, but related, virus. He used material from cowpox lesions to inoculate a person, who then showed immunity when later exposed to smallpox. This demonstrated that immunity to a related virus could prevent infection by the more dangerous smallpox virus, laying the groundwork for vaccination.

So the vaccine was developed to protect against smallpox, not malaria, polio, or diphtheria. The other diseases have their own distinct pathogens and later vaccines were developed specifically for them.