Antiviral Prophylaxis and Infant Vaccination to Prevent Perinatal Hepatitis B Infection

This is a prospective multi-center, multi-country (Thailand and Lao PDR), open-label, single arm clinical trial in HBsAg and HBeAg positive pregnant women (from 28 weeks until one year postpartum) and their infants (until 18 months of age). Pregnant women with HBsAg and HBeAg will receive tenofovir disoproxil fumarate 300 mg once daily from 28 weeks of pregnancy until two months postpartum. Their infants will receive hepatitis B (HB) immunization, starting with the first dose soon after birth.

The study aims to show that substituting maternal antiviral treatment for infant HBIg can be favorably considered in settings where HBIg plus vaccine has been used as well as in settings where only vaccine is used. A significant improvement over the standard HBIg + vaccine strategy would be that adding an antiviral strategy results in less than 2% transmission. A total of 499 women and their infants will be enrolled in public hospitals in Thailand and Lao PDR.

The study will be monitored by a Data and Safety Monitoring Board (DSMB) at least annually.

Inclusion criteria

• Pregnancy
• Age ≥18 years
• Negative HIV antibody test during current pregnancy
• Positive HBsAg test during current pregnancy
• Positive HBeAg using a rapid test during current pregnancy
• Absence of clinical symptoms of liver disease
• Gestational age of 28 weeks (+/- 7 days) based on the obstetrician judgment guided by the review of the date of last menstruation period.
• Willing and able to provide written informed consent
• Agreeing to bring her infants(s) at the planned study visits at one of the study site until the last visit (18 months after birth) and to inform the site investigators if plans to move to another place and not be able to return to the clinic
• Understand the need for adequate infant immunization for her infant(s) and accept that blood draws will be performed to determine the infant HBV infection status

Exclusion criteria

• Receipt of anti-HBV antivirals at any time during the last 9 months
• Known liver cirrhosis or evidence of hepatocellular carcinoma
• Creatinine clearance <50 ml/min, calculated using the Cockcroft-Gault formula
• Confirmed dipstick proteinuria >1+ (>30 mg/dL) or normoglycemic glycosuria
• Evidence of pre-existing fetal anomalies incompatible with life
• Any concomitant condition or treatment that, in the view of the clinical site investigator, would contraindicate participation or compromise adherence to treatment and satisfactory follow up in the study.