SMALLPOX VACCINATION STRAIN MVA - MARKER, GENETIC-STRUCTURE, EXPERIENCE GAINED WITH THE PARENTERAL VACCINATION AND BEHAVIOR IN ORGANISMS WITH A DEBILITATED DEFENCE MECHANISM

Abstract

The MVA virus is a lab virus ideally suited for vaccination of man and animals which can be differentiated from the known vaccinia strains by the use of numerous biological markers. Its reduced virulence for the chick embryo, for experimental animals and for man is a characteristic feature. With the exception of chick embryo fibroblasts, the MVA virus grows abortively in cell cultures. This applies particularly to cells of human origin in which the cytopathic effect and plaque formation are completely missing. The restriction analysis of the DNA of the MVA virus demonstrates that its genetic structure differs from that of the CVA basic virus and other orthopoxviruses. In contrast to the WHO reference strain Elstree, the MVA virus has a genome shortened by about 9%. The use of the MVA virus for human vaccination is particularly indicated in persons to be vaccinated for the 1st time and likely to entail a risk (on account of allergies, etc.) because it allows revaccination without complications. The MVA virus can be administered in intracutaneous, s.c. or i.m. injections. Innocuousness and successful vaccination were demonstrated in more than 120,000 persons. While other vaccinia strains such as the Elstree virus experience a drastic increase of virulence in the immunosuppressed organism (subjected to whole-body irradiation), the MVA virus cannot be activated in this situation.