Rabies vaccine: what should you know?

The rabies virus is estimated to be responsible for more than 50,000 deaths a year, though Australia is free from terrestrial rabies.

In Australia, rabies is subject to quarantine controls under Commonwealth biosecurity legislation - currently the Quarantine Act 1908. The primary concern is the prevention of the introduction of the rabies virus to local dog and wildlife populations.

There are two inactivated rabies cell culture-derived vaccines available in Australia:

• The Mérieux vaccine
• Rabipur

The rabies vaccine is effective and safe when used for pre-exposure prophylaxis (PreP) and post-exposure prophylaxis (PEP) for rabies virus.

Dosage of the vaccine
The dose of rabies vaccine for infants, children and adults for use in PreP and PEP is 1.0ml to be given by intramuscular injection.

HDCV can also be given by subcutaneous (SC) injection. However, if PCECV is inadvertently given via the SC route, the dose should be repeated.

Rabies vaccine should be given in the deltoid area, as rabies virus neutralising antibodies may be reduced after administration in other sites. In particular, vaccine should never be given in the buttock, as failure of pre-exposure prophylaxis has been reported when given by this route.

In infants under 12 months old, administration into the anterolateral aspect of the thigh is recommended.

Who should be vaccinated?
People who have occupations involving frequent contact with live animals (especially veterinarians, game rangers and animal welfare workers) should be vaccinated at the beginning of their careers.

World Health Organisation recommendations suggest that these individuals that are at high risk for exposure to rabies should receive rabies vaccine boosters (two doses, at zero and three days) every two years after a full course of immunisation. It is currently not recommended that rabies antibody titres be measured, but rather that prophylactic vaccination be given to all high risk individuals every two years after their primary series of vaccines.

However, if they are subsequently exposed to rabies they will need further booster vaccinations, i.e. two doses of vaccine immediately after the exposure.

After an animal bite the animal should be captured, if at all possible, avoiding further injuries to others. The state veterinary services should be called to capture sick or dangerous animals. An obviously sick animal may be immediately euthanased by a veterinarian to confirm or exclude rabies. Alternatively, the animal may be kept under observation.

Treatment should be given as early as possible. However, if a significant risk of rabies is recognised days or weeks or months after an animal bite, a course of rabies vaccination should still be given.

References:
Australian Department of Health, Rabies vaccines. http://www.health.gov.au/internet/main/publishing.nsf/Content/cdna-song-abvl-rabies.htm