A Vaccine for the Black Death

A Norwegian scientist claims to have solved the mystery behind the Black Death and to have created a vaccine against it.

Egil Lien, a professor at the University of Massachusetts, says "Our discovery explains one of the Black Death's greatest secrets. The bacteria has an incredibly clever way of fooling the immune system. It changes its surface so that the immune system doesn't manage to recognize it, and in this way is allowed to reproduce en masse."