Intradermal rabies vaccine
Gherardin, A.; Lau, S.
Medical Journal of Australia 187(1): 58-59
2007
ISSN/ISBN: 0025-729X PMID: 17605714 Document Number: 614698
Rabies vaccine is recommended for pre-exposure prophylaxis in travellers over one year of age who intend to travel to predominantly developing countries where canine rabies is endemic. Rabies vaccines currently available in Australia are given intramuscularly as 3 doses of 1.0 ml on Days 0, 7, and 21-28, but are relatively expensive at more than $100 per dose. Some travellers will choose not to be vaccinated because of this cost. For at-risk travellers who might choose to decline vaccination because of the cost, the WHO approves the intradermal route of vaccination, where 0.1 ml of vaccine is administered, also on Days 0, 7 and 21-28.2. However, the intradermal technique is technically more difficult, may result in lower antibody levels that decline more quickly, and may be interfered with by concurrent administration of chloroquine or immunosuppressants. The intradermal method has been utilized for over 10 years for travellers considered at high risk, but who decline vaccine on cost alone; imported human diploid cell vaccine of potency of at least 2.5 IU/ml is used. As several travellers can be vaccinated from the same vial, costs are $30-$40 per dose, and vials can be stored and reused within 7 days under aseptic conditions. However, travellers must be vaccinated 7-8 weeks before departure to enable antibody testing and a booster vaccination if required. Recent analysis of 1532 non-immunosuppressed travellers (aged between 9 and 77 years; 55% female) who received 3 intradermal doses of 0.1 ml rabies vaccine on Days 0, 7, and 21-28 in a clinic in Melbourne showed that only 7 (0.46%) failed to reach the protective antibody level of 0.5 IU/ml on testing 2-4 weeks after the third dose, with readings of 0.4 IU/ml (in 4), 0.3 IU/ml (in 2) and 0.2 IU/ml (in one). None had undetectable antibody levels. All 7 were advised to receive an intramuscular booster dose of 1.0 ml.