Rabies is a rare viral central nervous system infection most often transmitted to humans through the bite of an infected mammal. Rabies occurs worldwide, although most human deaths occur in Asia and Africa. The disease occurs very rarely in Canada. Since 1924, 26 people in Canada have died of rabies; the last human case acquired in Ontario was in 1967.
Rabies post-exposure prophylaxis should be given only if indicated by an evidence-based assessment of risk. Pre-exposure immunization and post-exposure prophylaxis are highly effective in preventing rabies.
According to the Canadian Immunization Guide, wound care is probably the most effective procedure in the prevention of rabies. Wound care is also important to prevent other infections transmitted by animals. Accordingly:
A four-Ws approach can be used to assess whether or not post-exposure prophylaxis is indicated for your patient.
Contact Toronto Public Health for assistance with the risk assessment.
|Patient is||Day 0||Day 3||Day 7||Day 14||Day 28|
|Not previously immunized against rabies and immunocompetent||Rabies vaccine and
Rabies Immune Globulin
|Rabies Vaccine||Rabies Vaccine||Rabies Vaccine||No further action|
|Not previously immunized against rabies and immunocompromised or on antimalarial drugs||Rabies vaccine and
Rabies Immune Globulin
|Rabies vaccine||Rabies vaccine||Rabies vaccine||Rabies vaccine|
|Previously immunized with a documented complete course of rabies vaccine (HDCV/PCECV).^||Rabies vaccine||Rabies vaccine||No further action||No further action||No further action|
|Previously immunized with a complete course of rabies vaccine without documentation||Serology prior to administering:
Rabies vaccine and
Rabies Immune Globulin
|Rabies vaccine||If an acceptable antibody concentration (0.5 IU/mL or greater) is demonstrated, the vaccine course may be discontinued, provided that at least two doses of vaccine have been given. Otherwise, administer the complete series based on patient immune status (as set out above).|
^Documentation of complete immunization with other types of rabies vaccine, or with unapproved schedules of HDCV/PCECV rabies vaccine, with demonstration of acceptable serology requires consultation with a Toronto Public Health Associate Medical Officers of Health.
To ensure timely receipt of serology results from the Public Health Ontario Laboratory to determine further treatment decisions for patients of animal exposures, health care providers must:
Vaccination schedules for post-exposure prophylaxis should be adhered to as closely as possible. It is essential that all doses be received. Doses should not be given early to allow for sufficient immune response between doses.
If a dose of vaccine is delayed, it should be given as soon as possible and the schedule resumed, preserving the spacing between intervals for subsequent doses. If there has been a significant deviation from the recommended vaccination schedule, immunity can be assessed with serology testing 7 to 14 days after the last vaccine dose.
There are no contraindications for rabies vaccine or RabIg after significant exposure to a proven rabid animal; however, care should be taken if PEP is to be administered to persons who are hypersensitive to the products or to any ingredient in the formulation or component of the container, including the following potential allergens:
Imovax® Rabies vaccine is preferred for patients with a history of hypersensitivity reactions to eggs or egg products. RabAvert® vaccine should only be administered to these persons if Imovax® rabies is not available and with strict medical monitoring.
Pregnancy and breastfeeding are not contraindications to post-exposure rabies prophylaxis.
Common adverse reactions include injection site reactions, such as pain, erythema, swelling, and itching. Serious side effects are rare.
Health care providers should record all vaccine doses and immune globulin administered to an individual in two places:
Rabies is spread to humans when the virus in the saliva of an infected animal enters through broken skin, the mucous membranes or the respiratory tract. Bites from an infected animal are the main route of exposure. Transmission also occurs through transplantation of organs from infected persons.
The virus gains access to the central nervous system through peripheral nerves. The usual incubation period is proportional to the distance from the portal of entry to the brain and may vary from several days to years (most commonly three to eight weeks).
Once clinical signs of rabies appear, the disease is nearly always fatal. Preliminary symptoms of rabies in human may be similar to the flu, such as weakness or discomfort, fever, or headache. In addition, there may also be discomfort, prickling, or an itching sensation at the site of the bite. Preliminary symptoms may last for days.
Following preliminary symptoms, progression of rabies includes cerebral dysfunction, anxiety, confusion, and agitation. In addition, as the disease further progresses, patients may experience delirium, abnormal behavior, hallucinations, hydrophobia (fear of water), and insomnia.
Pre-exposure prophylaxis is recommended for people at high risk of close contact with rabid animals or the rabies virus, including:
Pre-exposure immunization consists of three 1 mL IM doses in the deltoid of rabies vaccine (brand names: Imovax® Rabies, RabAvert®) given on day-0, day-7 and any time between days 21 to 28.
Toronto Public Health does not provide rabies pre-exposure prophylaxis. If your patient is a person at high risk of close contact with rabid animals or the rabies virus, they can be provided a prescription to obtain the vaccine from a local pharmacy, or referred to a travel medical clinic.
Health care providers should record all vaccine doses administered to an individual in two places:
The following measures can be taken to protect people and their pets from rabies:
Physicians have a duty to report animal-to-human exposures that in their opinion may result in the transmission of rabies under Regulation 557, Section 2(1), of the Health Promotion and Protection Act. Toronto Public Health can assist physicians with risk assessments, manage potentially rabid animals, and provide post-exposure prophylaxis (PEP) to requesting physicians.
Physicians have a duty to report suspected or confirmed human cases of rabies immediately to the Medical Officer of Health, under the Health Promotion and Protection Act.