Chromosomal aberrations in germ cells of male mice immunised with attenuated viral vaccines (human).

The cytogenetic effects of two attenuated viral vaccines (yellow fever vaccine and oral poliomyelitis vaccine) were assessed by means of the analysis of meiotic spermatocyte chromosomes in mice. In a dose of 0.5 ml, but not 0.1 ml, both vaccines induced a significant percentage of chromosomal aberrations after 7, 14 and 30 days. Euploidy was the major abnormality produced by yellow fever vaccine. The various abnormalities produced by oral polio vaccine were significant when pooled, but not when analysed individually. More abnormalities were produced by yellow fever vaccine than by oral polio vaccine.