Immunoprophylaxis failure against vertical transmission of hepatitis B virus: what is the mechanism and do other factors also play a role?

Post-partum reactivation of chronic hepatitis B virus infection among hepatitis B e-antigen-negative women

AIM: To investigate the frequency and timing of post-partum chronic hepatitis B virus (HBV) reactivation and identify its pre-partum predictors.

METHODS: Forty-one hepatitis B e antigen (HBeAg)-negative chronic HBV infected pregnant women were prospectively evaluated between the 28^th and the 32^nd week of gestation. Subjects were re-evaluated at 3-mo intervals during the first post-partum year and every 6 mo during the following years. HBV DNA was determined using real-time reverse transcription polymerase chain reaction (Cobas TaqMan HBV Test) with a lower detection limit of 8 IU/mL. Post-partum reactivation (PPR) was defined as abnormal alanine aminotransaminase (ALT) levels and HBV DNA above 2000 IU/mL.

RESULTS: Fourteen out of 41 women (34.1%) had pre-partum HBV DNA levels > 2000 IU/mL, 18 (43.9%) had levels < 2000 IU/mL and 9 (21.9%) had undetectable levels. Fourteen women were lost to follow-up (failure to return). PPR occurred in 8 of the 27 (29.6%) women evaluated, all within the first 6 mo after delivery (5 at month 3; 3 at month 6). Five of the 6 (83.3%) women with pre-partum HBV DNA > 10000 IU/mL exhibited PPR compared with 3 of the 21 (14.3%) women with HBV DNA < 10000 IU/mL (two with HBV DNA > 2000 and the third with HBV DNA of 1850 IU/mL), P = 0.004. An HBV DNA level ≥ 10000 IU/mL independently predicted post-partum HBV infection reactivation (OR = 57.02, P = 0.033). Mean pre-partum ALT levels presented a non-significant increase in PPR cases (47.3 IU/L vs 22.2 IU/L, respectively, P = 0.094).

CONCLUSION: In the present study, PPR occurred in approximately 30% of HBeAg-negative pregnant women; all events were observed during the first semester after delivery. Pre-partum HBV DNA level > 10000 IU/mL predicted PPR.

Management of chronic hepatitis B in pregnancy

Pregnancy associated with chronic hepatitis B (CHB) is a common and important problem with unique challenges. Pregnant women infected with CHB are different from the general population, and their special problems need to be considered: such as the effect of hepatitis B virus (HBV) infection on the mother and fetus, the effect of pregnancy on replication of the HBV, whether mothers should take HBV antiviral therapy during pregnancy, the effect of these treatments on the mother and fetus, how to carry out immunization of neonates, whether it can induce hepatitis activity after delivery and other serious issues. At present, there are about 350 million individuals with HBV infection worldwide, of which 50% were infected during the perinatal or neonatal period, especially in HBV-endemic countries. Currently, the rate of HBV infection in the child-bearing age group is still at a high level, and the infection rate is as high as 8.16%. Effective prevention of mother-to-child transmission is an important means of reducing the global burden of chronic HBV infection. Even after adopting the combined immunization measures, there are still 5%-10% of babies born with HBV infection in hepatitis B e antigen positive pregnant women. As HBV perinatal transmission is the main cause of chronic HBV infection, we must consider how to prevent this transmission to reduce the burden of HBV infection. In this population of chronic HBV infected women of childbearing age, specific detection, intervention and follow-up measures are particularly worthy of attention and discussion.