Hepatitis B infection in infants after neonatal immunization

Area of Science:

• Hepatology
• Immunology
• Pediatrics

Background:

• Hepatitis B virus (HBV) infection poses a significant risk to newborns born to carrier mothers.
• Effective prevention strategies are crucial to reduce the burden of chronic hepatitis B.

Purpose of the Study:

• To evaluate the efficacy of hepatitis B vaccine, with and without hepatitis B immune globulin (HBIG), in preventing chronic hepatitis B infection in infants born to HBeAg-positive carrier mothers.
• To determine the overall protection rates conferred by natural immunity, vaccination alone, and combined vaccine-HBIG strategies.

Main Methods:

• A double-blind, randomized, placebo-controlled trial involving 235 infants.
• Infants received heat-inactivated hepatitis B vaccine, with Group I receiving multiple HBIG doses, Group II a single HBIG dose, and Group III only the vaccine.
• Follow-up extended to three years to assess chronic infection and other hepatitis events.

Main Results:

• Chronic infection rates were 6.7% (Group I), 4.7% (Group II), and 1.6% (Group III) after three years.
• Natural protection was observed in 30% of infants.
• Vaccine alone protected 46%, single-dose HBIG added 10% protection, and multiple HBIG doses added 5% protection.
• Intrauterine infection occurred in 2%, and 7% failed to respond to immunization.

Conclusions:

• A significant proportion of infants born to hepatitis B carriers possess natural protection.
• Hepatitis B vaccination is a highly effective primary prevention method.
• The addition of HBIG, particularly multiple doses, offers incremental protection, but a notable percentage of infants may not respond to intensive immunization schedules.