Hepatitis A

Sexual transmission of hepatitis A virus (HAV) is linked to oro-anal contact, and is seen most often in men who have sex with men (MSM). The use of dental dams will help prevent transmission. HAV is also associated with injecting drug use. A vaccine is available to prevent transmission. The current recommendation is for a single dose of 1440 units (IU) intramuscularly in the deltoid muscle, with a booster 6 to 12 months later. Given the cost of hepatitis A vaccine, it is worth establishing that a person is non-immune prior to vaccinating.

The National Health and Medical Research Council's (NHMRC) Immunisation Handbook (external site) recommends that the following groups are among those who should receive hepatitis A vaccine:

  • MSM
  • people who inject drugs
  • patients with chronic liver disease.

Post-exposure prophylaxis

Below are the recommended doses of normal human immunoglobulin (NHIG) to be given as a single intramuscular injection to close contacts of hepatitis A cases within two weeks of exposure.

Weight Dose (NHIG)
Under 25 kg 0.5 mL
25–50 kg 1.0 mL
Over 50 kg 2.0 mL

Consider vaccination at a different site.

Public health issues

  • Notify WA Health of any cases of HAV.
  • All household and recent sexual contacts should be given normal human immunoglobulin prophylaxis (gamma globulin prophylaxis) (see above).
  • Contact tracing is important to prevent further transmission of HAV.
  • Offer vaccination for longer-term protection of at risk contacts. 

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