The influence of smallpox revaccination upon the foetus.

Serological, virological, anatomo- and histopathological investigations were performed in pregnant women subjected to smallpox revaccination. Serological findings were normal; no vaccinia virus was isolated from 210 placentae collected upon therapeutical abortion. Anatomopathological investigation of 15 placentae showed various lesions, while the embryo were free from any histopathological changes. The data prove that smallpox immunization does not affect the embryo directly, but only through the placenta.