Outcomes from a Canadian public health prenatal screening program for hepatitis B: 1997-2004.

BACKGROUND Without appropriate prophylaxis, the rate of vertical transmission of hepatitis B virus (HBV) can be as high as 95%. Alberta's provincial prenatal program screens all pregnant women for HBV, and provides prophylaxis to infants born to HBV-infected women. Canadian data on the outcomes of such programs are limited. METHODS We conducted a retrospective review of data from pregnant Albertan women who were Hepatitis B Surface Antigen (HBsAg) positive from 1997-2004. We describe the frequency of hepatitis B immunoglobulin (HBIG) and vaccine administration, follow-up serology and pregnancy outcomes. RESULTS In total, 1,485 HBsAg-positive pregnant women were identified; an average of 186 women annually (range: 125-216). Of the 980 infants eligible to have completed prophylaxis and serological follow-up, 82.0% were appropriately immunized and serologically tested, 11.3% had complete immunization but no serology testing and 6.6% were incompletely immunized. Of infants with complete immunization and follow-up, 3.7% failed to mount an immune response and 2.1% were infected. CONCLUSION A high proportion of infants born to carrier mothers are receiving appropriate post-natal prophylaxis in Alberta. Future research should examine maternal factors that may increase the vertical transmission of HBV.