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Screening and Post-Natal Prophylaxis Reduce Mother-to-Child HBV Transmission

Prenatal screening of pregnant women for hepatitis B virus (HBV), followed by immune prophylaxis for infants using injected hepatitis B antibodies and the first dose of the HBV vaccine given soon after delivery, resulted in a low rate of vertical HBV transmission -- less than 1 per 100 births -- in a real-world study described in the May 27 advance edition of Annals of Internal Medicine.

HBV, a blood-borne virus, can be transmitted from mother to child during gestation or delivery, and this is a common transmission route in some countries where hepatitis B is endemic. Infants infected with HBV usually become chronic carriers and are at elevated risk for developing cirrhosis and liver cancer later in life.

Ai Kubo and colleagues from Kaiser Permanente evaluated the effectiveness of a contemporary immunoprophylaxis protocol to prevent vertical transmission among participants in a large managed care organization.

Prior clinical trials have shown that giving babies hepatitis B immunoglobulin (HBIG) and the first of 3 HBV vaccine doses soon after birth reduces the risk of infection. The Centers for Disease Control and Prevention (CDC) recommends this type of immunoprophylaxis, but it has not been well-studied in community practice, the authors noted as background.

This retrospective observational studyincluded 4446 infants born to 3253 HBV positive mothers participating in a HBV perinatal immunoprophylaxis program within Kaiser Permanente Northern California between 1997 and 2010.

Mothers underwent hepatitis B surface antigen (HBsAg) testing to determine if they were infected. If so, their infants received immunoprophylaxis. Among mothers who received HBV DNA testing, 83 had viral loads of 50,000,000 IU/mL or greater, while 831 had less than 50,000,000 IU/mL. Although studies have found that antiviral therapy also helps reduce vertical HBV transmission, most of the mothers in this study did not receive hepatitis B treatment.

Results

• The overall infant HBV infection rate was 0.75 per 100 births.
• The infection rate was substantially higher for babies born to hepatitis B "e" antigen positive mothers -- indicating more viral replication -- compared with HBeAg negative mothers (3.37 vs 0.04 per 100 births, or 21 vs 1 infants, respectively).
• The infection rate was 3.61 per 100 births among mothers with HBV viral loads of 50,000,000 IU/mL or more, compared with 0 among mothers with less than 50,000,000 IU/mL, regardless of HbeAg status.
• The lowest HBV DNA level associated with transmission was 63,200,000 IU/mL.

"Prenatal HBV screening followed by postnatal prophylaxis is highly effective in preventing vertical transmission of HBV," the researchers concluded. "A negative e antigen status or a viral load less than [50,000,000 IU/mL] (90.9% of women tested) identifies women at extremely low risk for transmission after immunoprophylaxis who are unlikely to benefit from further interventions."

6/11/14

Reference

A Kubo, L Shlager, AR Marks, et al. Prevention of Vertical Transmission of Hepatitis B: An Observational Study. Annals of Internal Medicine. May 27, 2014 (Epub).