Rabies Vaccine – How many doses?
September 6th, 202316 Jan 2024
PRE exposure Rabies vaccination
Australian Immunisation Handbook, CDC ( USA Centre for Disease Control) and WHO (World Health Organisation), all recommend two pre-exposure rabies vaccinations given at least a week apart.
The vaccine can be given intradermally (ID) or intramuscularly (IM). IM is given at a slightly higher volume and deeper into the skin. ID can only be given to travellers under 50 years of age and in good general health. The medical staff administering the vaccine this way need special training as it is more technically difficult. Each visit for the Intradermal (ID) method is a dose in each arm, so it is really two ID injections on visit one and then another 2 ID injections at visit 2 in at least a week (total of 4 ). The ID injections themselves are very tiny and travellers find them less painful than IM administration.
If the travellers are exposed to a potentially rabies infected animal after proper PRE-exposure rabies vaccine, travellers do not need the RIG (Rabies Immune Globulin/ blood product with instant Rabies antibodies ) injected in the wound. This is good because often RIG is not available in countries where rabies is a risk.
Differences in guidelines for third dose
There are variations in the current guidelines for when to give a third dose
Australia – recommends a booster at one year or more if ongoing exposure
CDC says check serology or give a booster within three years.
(For those having intradermal rabies vaccine with a serology check, this fulfils the guidelines of CDC)
WHO does not specify the need for a booster after 2 doses
Everyone specifies you need 2 boosters AFTER you are bitten, licked or scratched by a potentially infected animal. This is called post-exposure treatment.
Recommendation from Dr Deb
For travellers, I recommend 2 doses of rabies vaccine before a trip, and then a booster before the next trip.
This spreads the cost across two trips and likely gives stronger protection. From a theoretical point of view, we know the immune system works better if it has more time between doses of vaccine to process the antigen through the immune system.
i.e. You don’t need to “finish the course” of rabies vaccine, like you do with other vaccines such as the Hepatitis A or B vaccine courses
If there is no time for two doses before departure?
For people leaving at short notice, it IS worth having at least one dose of rabies vaccine, to give your immune system a head start on the virus. This is especially important because OFTEN after a risk exposure in an under-resourced part of the world, one is recommended to get RIG (Rabies Immune Globulin/ blood product with instant Rabies antibodies ) injected in the wound, but RIG is just not readily available.
More info on our BORS trial of one dose (last-minute) traveller research
https://www.thetraveldoctor.com.au/borsinfo/
Why do guidelines differ?
Although there is one body of knowledge in the world, different medical groups assess that information differently.
They also take variable amounts of time to update their guidelines
Timing for Guidelines
WHO made their guidelines in April 2018
https://www.who.int/publications/i/item/who-wer9316
The CDC updated their guidelines May 2022
https://www.cdc.gov/mmwr/volumes/71/wr/mm7118a2.htm
The Australian Guidelines were only updated 13 Dec 2023
i.e. Guidelines may take a while to get updated
