IMMUNE-RESPONSE TO HEPATITIS-B VACCINE IN PREGNANT-WOMEN RECEIVING POSTEXPOSURE PROPHYLAXIS

Hepatitis B immunoglobulin and vaccine were given as post-exposure pro phylaxis to 73 women after an outbreak of hepatitis B due to in vitro fertilization treatment. The immunization schedule consisted of 5 ml o f hepatitis B immunoglobulin (125 IU/ml) at months 0 and 1 and recombi nant hepatitis B vaccine (10 mug of HBvaxDNA) at months 0, 1, 2 and 6. The safety and immunogenicity of hepatitis B vaccine were studied in 16 women who became pregnant after in vitro fertilization; 57 non-preg nant women receiving the same treatment served as controls. Blood samp les were drawn at 0, 1, 2, 6 and 7 months. One patient had a clinical abortion 2 days after initial immunization; other side effects of vacc ination were not found in vaccinees or in their offspring. All vaccine es exhibited antibodies against hepatitis B surface antigen after vacc ination but relatively low peak geometric mean titers of 258 IU/l and 684 IU/l were attained in pregnant and non-pregnant women, respectivel y. There were no significant differences in seroconversion rates and g eometric mean titers between the two groups although the immune respon se to hepatitis B vaccine was slower and lower in pregnant women at al l times. Our results suggest that when post-exposure prophylaxis for h epatitis B infection is indicated, passive active immunization can be started safely during pregnancy. The relative weak response to the vac cine calls for monitoring of the anti-HBs 1 month after the initial se ries of vaccinations.