Effect of obligatory Hepatitis B vaccination program on the prevalence of occult hepatitis B among pregnant women in Egypt: A cross sectional study.

Hepatitis B virus (HBV) infection is a global health problem. HBV is of intermediate endemicity in Egypt. "Occult" HBV (OBI) indicates replication of HBV-DNA in the liver of individuals with negative serum HBsAg. This study aimed to determine the prevalence of OBI among pregnant women in Egypt and to compare this prevalence among HBV vaccinated and unvaccinated women (received obligatory vaccination). This cross-section study included 474 pregnant women in the third trimester divided in two groups. Group I: (n=247) assumed received obligatory hepatitis B vaccination and group II: (n=227), did not receive HBV vaccination. Study participants were screened for HBsAg, anti HBs, anti HBc total, anti HBc IgM, HBeAg, anti HBe, HCV Ab, and HIV Ab by immunoassays and HBV-DNA by Real-Time PCR. Anti HBs was detected in 65 (13.7%) of pregnant women, 36 (14.6%) in the vaccinated group and 29 (12.8%) in the unvaccinated group. The anti HBs levels were significantly higher in the unvaccinated group. HBc Ab showed positive results in 6 cases (2.4%) in the vaccinated group, and 14 cases (6.2%) in unvaccinated group. HBcAb and/or HBsAb were detected in 72 (15.1%) of pregnant women, 39 (15.8%) in the vaccinated group and 33 (14.5%) in the unvaccinated group. HBV-DNA was detected only in one vaccinated pregnant woman. HB vaccination program in Egypt, since 1992 affected the frequency of OBI in pregnant women (p=0.04). In conclusion, HBV infection may persist lifelong in the hepatocytes even when viral functions are suppressed, HBsAb and anti-HBc-positive individuals are present. The levels of HBsAb were higher in unvaccinated pregnant women compared to vaccinated pregnant women. HBV infection in OBI pregnant women may not transmit to the new-born.