Hepatitis B Vaccine:
Protecting Your Child's Liver for Life

Hepatitis B is a virus that silently destroys the liver over decades. In Asia, it is the leading cause of liver cancer — and yet it is entirely preventable with a vaccine that starts on the day of birth. This is one of the rare cases in medicine where a single injection at birth can protect against cancer in middle age.

Singapore's Hepatitis B Context

Hepatitis B is the leading cause of hepatocellular carcinoma (liver cancer) in Asia. Singapore's universal infant immunisation programme, launched in 1987, has been one of the most impactful public health interventions in the country's history — transforming a high-burden nation into one where the next generation is largely protected.

What Hepatitis B Does

Hepatitis B virus (HBV) is transmitted through blood and body fluids. It attacks liver cells, triggering inflammation. In most infected adults, the immune system clears the infection within 6 months. But in children infected at a young age, the story is very different:

• Infected at birth: 90% become chronic carriers
• Infected as a toddler (1–5 years): 25–50% become chronic carriers
• Infected as an adult: only 5% become chronic

The younger the infection, the more likely it becomes chronic — because infants' immune systems are not yet equipped to fight it off. And chronic hepatitis B is insidious: most people feel completely well for decades while the virus quietly damages the liver. The endpoint is cirrhosis, liver failure, or liver cancer — typically in the 4th or 5th decade of life.

Why the Birth Dose Matters

In Asia, the most common route of hepatitis B transmission is mother to child during delivery. An HBsAg-positive mother can transmit the virus to her baby during labour. The birth dose of hepatitis B vaccine, given within 24 hours of delivery (and ideally within 12 hours), primes the immune system before any viral exposure can establish chronic infection.

For babies born to HBsAg-positive mothers, the birth dose is given together with hepatitis B immunoglobulin (HBIG) — an additional layer of passive protection.

The Vaccine

Options

• Engerix-B (GSK) — 10 mcg/0.5 ml for children; given as a standalone injection at birth
• Part of Infanrix Hexa (6-in-1) — hepatitis B component included in the combined vaccine at 2, 4, and 6 months

Schedule

• Dose 1: At birth (within 24 hours, ideally within 12 hours)
• Doses 2, 3: Incorporated into the 6-in-1 vaccine at 2 months and 6 months (or 2/4/6 months in some schedules)

Claimability

Hepatitis B vaccination is part of Singapore's National Childhood Immunisation Schedule (NCIS) and is claimable under MediSave. It is also compulsory under the Infectious Diseases Act.