Vaccination is necessary to everyone!

Already at the beginning of the social developments the mankind met devastating consequences of epidemics. Then there was the unknown a reason of epidemics, communication between them. But it was noticed that the new wave of an illness spares those people who already transferred it earlier. This phenomenon was described in 430 B.C. by the historian Fukidid: "Most of all the suffering and death spare those who already recovered from an illness. They are familiar with an illness and any more are not afraid of it because know that plague never affects the person twice, at least is deadly". Certainly, scientists since those old times tried to find the reason of diseases...