A review and a study this month help delineate a strategy to lower the rate of HBV transmission (Clin Gastro Hepatol 2012; 10: 452-59 & 520-526). Overall, using HBIG and HBV vaccine within 12 hours of birth (followed by two additional doses of vaccines within 6-12 months) prevents about 95% of HBV transmission from HBsAg-positive mothers to their infants. This has made a huge difference. Yet, among mothers with high levels of viremia, HBV is still transmitted in 8-30%. As such, this review proposes an algorithm to reduce mother to child transmission (MTCT).
The key risk factor is HBV DNA levels >200,000 IU/mL; the most effective way to reduce transmission from highly-viremic mother to infancts is the use of antiviral therapy. The authors recommend that in addition to the usual preventive measures (HBIG/HBV vaccine within 12 hours of birth), that efforts to lower MTCT include use of either lamivudine (pregnancy category C), telbivudine (pregnancy category B), or tenofovir (pregnancy category B) at the 3rd trimester in the following:
- Infected women with high HBV DNA levels
- Infected women who have had children who have failed previous prophylaxis
- Infected women with threatened pre-term labor
In addition, elective C-section should be considered if HBV DNA >20 million IU/mL at full term.
The second citation refers to an open-label prospective study of 88 HBe-Ag positive women. All women had HBV DNA >6 log10 copies/mL and increased ALT. Telbivudine (600 mg/day) was administered to 53 women starting between 12 and 30 weeks gestation; there were 35 control patients who all received HBIG/HBV vaccine. In the treatment group, none of the infants developed HBV infection. In the control group, the transmission rate was 8.6%. No significant adverse effects were noted; specifically, no congenital malformations were noted.
Related blog entry/additional references:
- Looking for trouble
- -Gastroenterol 2007; 132: 1287. Two decades of HBV vaccination in Taiwan.