8 Hepatitis B

Key information

Mode of transmission Contact with infected blood or body fluids during childbirth (vertical transmission); sexual intercourse, intravenous drug use, or contact with broken skin (horizontal transmission).
Incubation period 45–180 days, commonly 60–90 days.
Period of communicability Potentially infectious 2–3 weeks before the onset of symptoms, during the clinical disease and usually for 2–3 months after acute hepatitis B illness; as long as HBsAg continues to be present in blood.
Burden of disease New Zealand is a country with a low overall prevalence of hepatitis B carriage, but it contains certain populations with high prevalence.

All pregnant women and high-risk groups should be screened for chronic infection.

HBV acquisition in infancy is very likely to lead to chronic infection.

Chronic HBV infection can progress to cirrhosis and liver cancer.
Funded vaccine Hep B (HBvaxPRO).

DTaP-IPV-HepB/Hib (Infanrix-hexa).
Funded vaccine indications and schedule At ages 6 weeks, 3 months and 5 months:

Babies born to HBsAg-positive mothers: Hep B plus HBIG at birth, then the usual childhood schedule. Serological testing (anti-HBs and HBsAg at age 9 months).

Unvaccinated children aged under 18 years: 3 doses of Hep B, at 0, 1 and 6 months (an accelerated schedule is available).

Eligible adults: 3 doses of Hep B, at 0, 1 and 6 months (an accelerated schedule is available).
Vaccine efficacy/effectiveness Protection is expected to be lifelong. Boosters are not recommended.