Rabies Vaccine: Questions and Answers

• How common is human rabies?
• When should people be vaccinated against rabies?
• How much vaccine is used for post-exposure versus pre-exposure treatment?
• Why is there a limited supply of rabies vaccine in Canada?
• What was the nature of the production problems experienced by Aventis?
• Will rabies vaccine still be available to Canadians during this period of instability?
• Does an expedited review of a vaccine compromise the safety of that vaccine?
• Why is it important to use approved vaccines in Canada?
• What is the Special Access Program?
• Will use of the Special Access Program result in a delay in acquiring vaccine?
• Will vaccine be available to private providers?
• Will vaccine be available for clients who have started but not completed their pre-exposure vaccine series?

Q. How common is human rabies?

A. Human rabies is rare in Canada, due largely to excellent prevention and control programs. There have been only two reported cases in Canada since 1985. Both cases were associated with exposure to bats. There were 22 human rabies cases in Canada between 1924 and 2000.

Rabies is a significant public health problem in many Asian and African countries. The World Health Organization estimates there are 55,000 human deaths from rabies each year in Asia and Africa, with 30-50% of cases occurring in children under 15 years of age.

Q. When should people be vaccinated against rabies?

A. Rabies is a serious disease that is almost always fatal, so post-exposure vaccination is a priority for anyone exposed to animals with proven or suspected rabies. Post-exposure vaccines in Canada are distributed through the public health system.

Rabies vaccine is also indicated for pre-exposure vaccination of people who are at high risk of contact with potentially rabid animals or the rabies virus. This includes, for example, certain laboratory workers, veterinarians, animal control and wildlife workers, spelunkers (cave explorers), hunters and trappers in high-risk areas and travellers to endemic areas. Pre-exposure vaccination is generally offered by private health care providers (e.g. travel clinics); some provinces offer publicly funded pre-exposure vaccine programs.

Q. How much vaccine is used for post-exposure versus pre-exposure treatment?

A. About 65 per cent of the annual doses of rabies vaccine in Canada is used for post-exposure vaccination; the remaining 35% is used for pre-exposure prophylaxis.

Q. Why is there a limited supply of rabies vaccine in Canada?

A. In August 2004, Aventis Pasteur advised the Public Health Agency of Canada and Canadian Immunization Committee (CIC) that production problems would result in a global shortage of Imovax Rabies, the only approved rabies vaccine in Canada. Initially, the manufacturer expected the supply to be re-established in September 2005. The period of supply instability is now expected to last until early 2006.

Q. What was the nature of the production problems experienced by Aventis?

A. Aventis reported in August 2004, that a non-inactivated production strain of the virus had been discovered in a single product lot. This lot was not distributed. Aventis suspended production and recalled all lots of rabies vaccine manufactured during the same time frame. None of the recalled lots had been distributed in Canada. Given the global shortfall of Imovax rabies vaccine, Aventis has indicated that a period of supply instability is expected to last until early 2006.

Q. Will rabies vaccine still be available to Canadians during this period of instability?

A. Yes. Since being informed of an expected shortage, the Public Health Agency of Canada has been working closely with the provinces and territories, the Canadian Immunization Committee, the National Advisory Committee on Immunizations, and the National Committee to Advise on Tropical Medicine and Travel (CATMAT) to address this issue.

To ensure that a rabies vaccine is available to Canadians, PHAC is assisting in the identification of suppliers who are willing to submit their products for approval for use in Canada. Health Canada is currently conducting an expedited review of Chiron's Rabavert vaccine and is expected to complete this review during Spring 2005.

At the same time, the provinces and territories are collaborating to manage the supply of the remaining stocks of Imovax Rabies vaccine. This may involve re-allocating available doses amongst jurisdictions across Canada.

It is possible that remaining stocks of the approved Imovax Rabies vaccine will be depleted before the approval of an alternate vaccine. In this case, vaccines that are approved for use in other countries can be obtained through Health Canada's Special Access Program (SAP).

Q. Does an expedited review of a vaccine compromise the safety of that vaccine?

A. No. The vaccine that is under review must still meet all Health Canada requirements for safety and effectiveness before it receives market authorization in Canada. An expedited review is not an abbreviated review; it continues to be a full review of the safety and efficacy of the vaccine performed in an expedited manner.

Q. Why is it important to use approved vaccines in Canada?

A. A vaccine is only approved once it has met all Health Canada requirements for safety and effectiveness. In general, only products that have received a Notice of Compliance from by Health Canada should be used. In situations where an approved vaccine is unavailable but is needed on an urgent basis (or to prevent a serious illness) based on an assessment by the health care provider, vaccines that are not approved for distribution in Canada may be acquired on an interim basis through the Special Access Program. Information on the vaccine provided through the Special Access Program will be made available to the physician to assist with their risk assessment and informed consent process when consulting with their clients.

Q. What is the Special Access Program?

A. Health Canada's Special Access Programme has a mandate to provide access to nonmarketed drugs for practitioners treating patients with serious or life-threatening conditions when other therapies have either failed, are unsuitable or unavailable. Further information about the SAP and the information required to initiate a request can be found on the SAP website (http://www.hc-sc.gc.ca/hpfb-dgpsa/tpd-dpt/index_sap_drugs_e.html) or by calling 613-941-2108.

Q. Will use of the Special Access Program result in a delay in acquiring vaccine?

A. The Special Access Programme makes every effort to process requests within 24 hours of receipt.

Q. Will vaccine be available to private providers?

A. In the event that supplies of the approved Imovax Rabies vaccine are depleted prior to the approval of another product in Canada, private providers can access other vaccine using the Special Access Program.

Q. Will vaccine be available for clients who have started but not completed their pre-exposure vaccine series?

A. Vaccine is expected to be available to individuals for completing their rabies vaccine series, either using the approved vaccine or vaccines available through the SAP. The National Advisory Committee on Immunization (NACI) will be providing recommendations on the interchangeability of rabies vaccines. The need to complete a rabies vaccine series in times of supply shortage should be assessed for each individual, based on an assessment of the risks and benefits of an interruption to the schedule.