The effect that the study is examining is known as cross-protection, where a mild infection provides immunity against a more dangerous strain.
It has been examined in a wide variety of illnesses and was the foundation for early vaccine research.
The early vaccines for smallpox were made by deliberately infecting people with cowpox.
One review published in med hypotheses described the scientist, Edward Jenner as “both lucky and crazy” for the fact that his use of cowpox did protect people against smallpox.
Source: | This article first appeared on Express.co.uk