[The sexual transmission of Australia antigen (HBsAg)].

Examination was made of 300 serum specimens taken from patients with latent syphilis, in order to study the incidence of HBsAg antigen as compared with the normal population. Examination was by means of counter immunoelectrophoresis, radioimmunoassay and electron microscope with negative staining. The incidence as shown by counter immunoelectrophoresis is 2.33%, by RIA 10% with 86.6% of sub-type AY and 13.3% of sub-type AD, which is significantly higher than the incidence in the normal population. These data would therefore seem to confirm the possibility of sexual transmission of hepatitis B.