[Smallpox--historical or real threat].

Presently, there is no real possibility of natural re-emergence of smallpox virus, which was eradicated globally more then 25 years ago. During the last decade the possibility of use of smallpox virus as a biological weapon by a criminal organisation was emphasised. The re-emergence of smallpox virus would lead to unprecedented disaster. Theoretical models indicated that only extremely strict and enforced interventions could stop the spread of epidemic, but the assumptions of these models were unrealistic. Presently, there are limited stocks of the first generation smallpox vaccine left in the world. This vaccine, as well as the second-generation vaccine are associated with multiple adverse events, including fatalities and may not be accepted by society. Much safer vaccines are now being developed. Strategic plan of prophylactic vaccinations requires defining the groups to be immunised in the first place and whether immunisation should start before or after a first smallpox case would occur.