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Rationale Of treatment
The following factors should be considered before antirabies prophylaxis is initiated.
Species of biting animal
Rabid bats have been documented in the 49 continental states, and bats are increasingly implicated as important wildlife reservoirs for variants of rabies virus transmitted to humans. Transmission of rabies virus can occur from minor, seemingly underappreciated or unrecognized bites from bats (see Table 2).11
Wild Terrestrial Carnivores
Raccoons, skunks, and foxes are the terrestrial carnivores most often infected with rabies in the United States. Suggestive clinical signs of rabies among wildlife cannot be interpreted reliably. All bites by such wildlife should be considered possible exposures to rabies virus. Post-exposure prophylaxis should be initiated as soon as possible following exposure to such wildlife, unless the animal is available for diagnosis and public health authorities are facilitating expeditious laboratory testing, or if the brain tissue from the animal has already tested negative (see Table 2).11
Other Wild Animals
Small rodents (eg, squirrels, chipmunks, rats, mice, hamsters, guinea pigs, and gerbils) and lagomorphs (including rabbits and hares) are rarely infected with rabies and have not been known to transmit rabies to humans. In all cases involving rodents, the state or local health department should be consulted before a decision is made to initiate post-exposure prophylaxis (see Table 2).11
Domestic Dogs, Cats, and Ferrets
The likelihood of rabies in a domestic animal varies regionally, and the need for post-exposure prophylaxis also varies on the basis of regional epidemiology (see Table 2).11
Circumstances Of Biting Incident
An unprovoked attack might be more likely than a provoked attack to indicate the animal is rabid. Bites inflicted on a person attempting to feed or handle an apparently healthy animal should generally be regarded as provoked. Consult the local or state health department following a provoked or unprovoked exposure to determine the best course of action based on current public health recommendations.
Type of exposure
Rabies is transmitted by introducing the virus into open cuts or wounds in skin or via mucous membranes. The likelihood of rabies infection varies with the nature and extent of exposure. Two categories of exposure should be considered, bite and nonbite.
Any penetration of the skin by teeth.
Scratches, abrasions, open wounds, or mucous membranes contaminated with saliva or other potentially infectious material, such as brain tissue, from a rabid animal. Casual contact, such as petting a rabid animal, (without a bite or nonbite exposure as described above), does not constitute an exposure and is not an indication for prophylaxis. Rare reports of airborne rabies have been received from laboratory and bat-infested cave settings.11
Rare cases of rabies from human-to-human transmission have occurred in patients in the US and overseas who received organs transplanted from persons who died of rabies undiagnosed at the time of death. No documented laboratory-diagnosed cases of human-to-human rabies transmission have been documented from a bite or nonbite exposure other than the transplant cases. At least two cases of human-to-human rabies transmission in Ethiopia have been suggested, but rabies as the cause of death was not confirmed by laboratory testing. The reported route of exposure in both cases was direct salivary contact from another human (ie, a bite and a kiss). Routine delivery of health care to a patient with rabies is not an indication for post-exposure prophylaxis unless the healthcare worker is reasonably certain that he or she was bitten by the patient or that his or her mucous membranes or nonintact skin was exposed directly to potentially infectious saliva or neural tissue.11
Pre- And Post-Exposure Prophylaxis Of Rabies
Pre-exposure immunization should be offered to rabies researchers, certain laboratory workers and other persons in high-risk groups, such as veterinarians and their staff, and animal handlers. Pre-exposure vaccination also should be considered for persons whose activities bring them into frequent contact with rabies virus or potentially rabid bats, raccoons, skunks, cats, dogs, or other species at risk for having rabies. In addition, some international travelers might be candidates for pre-exposure vaccination if they are likely to come in contact with animals in areas where dog or other animal rabies is enzootic and immediate access to appropriate medical care, including rabies vaccine and immune globulin, might be limited.11
Vaccination is recommended for children living in or visiting countries where exposure to rabid animals is a constant threat. Worldwide statistics indicate children are more at risk than adults. Pre-exposure prophylaxis is administered for several reasons. First, although pre-exposure vaccination does not eliminate the need for additional medical evaluation after a rabies exposure, it simplifies management by eliminating the need for Rabies Immune Globulin (RIG) and decreases the number of doses of vaccine needed. This is particularly important for persons at high risk for being exposed to rabies in areas where modern immunizing products might not be available or where cruder, less safe biologics might be used, placing the exposed person at increased risk for adverse events. Second, pre-exposure prophylaxis might offer partial immunity to persons whose post-exposure prophylaxis is delayed. Finally, pre-exposure prophylaxis might provide some protection to persons at risk for unrecognized exposures to rabies.11
Pre-Exposure Rabies Prophylaxis Guide
Pre-exposure prophylaxis consists of three 1.0 mL doses of Imovax Rabies vaccine administered intramuscularly, using a sterile needle and syringe, one injection per day on Days 0, 7, and 21 or 28. In adults and older children, the vaccine should be administered in the deltoid muscle. In infants and small children, the anterolateral aspect of the thigh may be preferable, depending on age and body mass.
Administration of booster doses of vaccine depends on exposure risk category and serologic testing as noted in Table 1.
Immunosuppressed persons should postpone pre-exposure vaccinations and consider avoiding activities for which rabies pre-exposure prophylaxis is indicated. When this course is not possible, immunosuppressed persons who are at risk for rabies should have their viral neutralizing antibody titers checked after completing the pre-exposure series. If no acceptable antibody response is detected, the patient should be managed in consultation with their physician and appropriate public health officials.11
Table 1: Rabies Pre-exposure Prophylaxis Guide11
|Risk category||Nature of risk||Typical populations||Pre-exposure recommendations|
|Continuous||Virus present continuously and often in high concentrations. Specific exposures likely to go unrecognized. Bite, nonbite, or aerosol exposure.||Rabies research laboratory workers; rabies biologics production workers.||Primary course. Serologic testing every 6 months; booster vaccination if antibody titer is below acceptable level.*|
|Frequent||Exposure usually episodic, with source recognized, but exposure also might be unrecognized. Bite, nonbite, or aerosol exposure.||Rabies diagnostic laboratory workers, cavers, veterinarians and staff, and animal-control and wildlife workers in areas where rabies is enzootic. All persons who frequently handle bats.||Primary course. Serologic testing every 2 years; booster vaccination if antibody titer is below acceptable level.*|
|Infrequent (greater than population at large)||Exposure nearly always episodic with source recognized. Bite or nonbite exposure.||Veterinarians and animal-control staff working with terrestrial animals in areas where rabies is uncommon to rare. Veterinary students. Travelers visiting areas where rabies is enzootic and immediate access to appropriate medical care including biologics is limited.||Primary course. No serologic testing or booster vaccination.|
|Rare (population at large)||Exposure always episodic with source recognized. Bite or nonbite exposure.||US population at large, including persons in areas where rabies is epizootic.||No vaccination necessary.|
|*Minimum acceptable antibody level is complete virus neutralization at a 1:5 serum dilution by the rapid fluorescent focus inhibition test. A booster dose should be administered if the titer falls below this level.|
The essential components of rabies post-exposure prophylaxis are wound treatment and, for previously unvaccinated persons, the administration of both human rabies immune globulin (RIG) and vaccine.11
Local treatment of wounds
Thorough washing and flushing (for about 15 minutes, if possible) with soap or a cleansing agent and copious amounts of water of all bite wounds and scratches should be done immediately or as early as possible. Where available, an iodinecontaining, or similarly viricidal, topical preparation should be applied to the wound.12
Tetanus prophylaxis and measures to control bacterial infection should be given as indicated.
The sooner treatment is begun after exposure, the better. Post-exposure antirabies vaccination should always include administration of both passive antibody and vaccine, with the exception of persons who have ever previously received complete vaccination regimens (pre-exposure or post-exposure) with a cell culture vaccine or persons who have been vaccinated with other types of vaccines and have previously had a documented rabies virus neutralizing antibody titer. These persons should receive only vaccine (ie, post-exposure for a person previously vaccinated). The combination of RIG and vaccine is recommended for both bite and nonbite exposures reported by persons who have never been previously vaccinated for rabies, regardless of the interval between exposure and initiation of prophylaxis. If post-exposure prophylaxis has been initiated and appropriate laboratory diagnostic testing (ie, the direct fluorescent antibody test) indicates that the exposing animal was not rabid, post-exposure prophylaxis can be discontinued.11
Treatment outside the United States
If post-exposure is begun outside the United States with locally produced biologics, it may be desirable to provide additional treatment when the patient reaches the US. State or local health departments should be contacted for specific advice in such cases.11
Post-Exposure Rabies Prophylaxis Guide
The following recommendations are only a guide. In applying them, take into account the animal species involved, the circumstances of the bite or other exposure, the vaccination status of the animal, the availability of the exposing animal for observation or rabies testing, and the presence of rabies in the region (see Table 2). Local or state public health officials should be consulted if questions arise about the need for rabies prophylaxis.11
Table 2: Post-exposure Treatments Guide11
|Animal type||Evaluation and disposition of animal||Post-exposure prophylaxis recommendations|
|Dogs, cats, and ferrets||Healthy and available for 10 days observation.
Rabid or suspected rabid.
Unknown (eg, escaped).
|Persons should not begin prophylaxis unless animal develops clinical signs of rabies.*
Immediately begin prophylaxis.
Consult public health officials.
|Skunks, raccoons, foxes, and most other carnivores; bats †||Regard as rabid unless animal proven negative by laboratory tests. ‡||Consider immediate prophylaxis.|
|Livestock, small rodents (rabbits and hares), large rodents (woodchucks and beavers), and other mammals||Consider individually.||Consult public health officials. Bites from squirrels, hamsters, guinea pigs, gerbils, chipmunks, rats, mice, other small rodents, rabbits, and hares almost never require anti-rabies postexposure prophylaxis.|
|* During the 10-day observation period, begin
post-exposure prophylaxis at the first sign of rabies in a dog, cat, or ferret
that has bitten someone. If the animal exhibits clinical signs of rabies, it
should be euthanized immediately and tested.
† Post-exposure prophylaxis should be initiated as soon as possible following exposure to such wildlife unless the animal is available for testing and public health authorities are facilitating expeditous laboratory testing or it is already known that brain material from the animal has tested negative. Other factors that might influence the urgency of decision-making regarding initiation of post-exposure prophylaxis before diagnostic results are known include the species of the animal, the general appearance and behavior of the animal, whether the encounter was provoked by the presence of a human, and the severity and location of bites. Discontinue vaccine if appropriate laboratory diagnostic test (ie, the direct fluorescent antibody test) is negative.
‡ The animal should be euthanized and tested as soon as possible. Holding for observation is not recommended.
DOSAGE AND ADMINISTRATION
Parenteral drug products should be inspected for particulate matter and discoloration prior to administration, whenever solution and container permit. The syringe and its package should also be inspected prior to use for evidence of leakage, premature activation of the plunger, or a faulty tip seal. If evidence of such defects is observed, the product should not be used.
The package contains a vial of freeze-dried vaccine, a syringe containing 1.0 mL of diluent, a plunger for the syringe, and a sterile needle for reconstitution. Cleanse the vaccine vial stopper with a suitable germicide. Do not remove the stopper or the metal seal holding it in place. Attach the plunger and reconstitution needle to the syringe and reconstitute the freeze-dried vaccine by injecting the diluent into the vaccine vial. Gently swirl the contents until completely dissolved and withdraw the total contents of the vial into the syringe. Remove the reconstitution needle and discard. Attach a sterile needle of your choice that is suitable for intramuscular injection of your patient.
The supplied syringe is intended for single use only, must not be reused, and must be disposed of properly and promptly following its use.
To help avoid transmission of infectious diseases due to accidental needle sticks, needles should not be recapped but disposed of according to recommended guidelines.
The reconstituted vaccine should not be mixed with any other vaccine and should be used immediately.
After preparation of the injection site with an appropriate germicide, immediately inject the vaccine intramuscularly. For adults and older children, the vaccine should be injected into the deltoid muscle.10,18,19 In infants and small children, the anterolateral aspect of the thigh may be preferable, depending on age and body mass. Care should be taken to avoid injection into or near blood vessels and nerves. If blood or any suspicious discoloration appears in the syringe, do not inject but discard contents and repeat procedure using a new dose of vaccine at a different site.
The gluteal area should not be used for administration of the vaccine as administration in this area may result in lower neutralizing antibody titers.11
NOTE: The freeze-dried vaccine is creamy white to orange. After reconstitution, it is pink to red.
In the United States, the Immunization Practices Advisory Committee (ACIP) recommends three injections of 1.0 mL each, one injection on Day 0, one on Day 7, and one either on Day 21 or 28.11
A booster dose consists of one injection of 1.0 mL of Imovax Rabies vaccine. To ensure the presence of a primed immune response over time among persons at higher than normal risk for exposure, titers should be checked periodically, with booster doses administered only as needed. Persons working with live rabies virus in research laboratories and in vaccine production facilities (continuous risk category) should have rabies antibody titers checked every six months and boosters given as needed to maintain an adequate titer defined as virus neutralization at a 1:5 dilution by a RFFIT. Other laboratory workers (eg, those performing rabies diagnostic testing), cavers, veterinarians and staff, animal-control and wildlife officers in areas where rabies is enzootic, and bat handlers regardless of location, (frequent risk category), should have their serum tested for rabies antibody every 2 years. If their titer is inadequate, they should receive a single booster dose of vaccine. Veterinarians, veterinary students, and terrestrial animalcontrol and wildlife officers, working in areas of low rabies endemicity (infrequent risk category) and certain at-risk international travelers who have completed a full pre-exposure vaccination series with licensed vaccines and according to schedule do not require routine booster serologic verification of detectable antibody titers or routine pre-exposure booster doses of vaccine (see Table 1).11
Persons who have experienced “immune complex-like” hypersensitivity reactions should receive no further doses of Imovax Rabies vaccine unless they are exposed to rabies or they are truly likely to be inapparently and/or unavoidably exposed to rabies virus and have unsatisfactory antibody titers.
Post-exposure dosage for previously unimmunized persons
Dose: Previously unvaccinated persons should receive 5 intramuscular doses (1 mL each) of Imovax Rabies vaccine, one dose immediately after exposure (Day 0) and one dose 3, 7, 14, and 28 days later.
RIG: Rabies immune globulin (RIG) 20 IU/kg on Day 0 in conjunction with the first vaccine dose. If possible, the full calculated dose of RIG should be used to infiltrate the wound(s). If it is not possible to do so, any remaining portion of the dose should be administered intramuscularly at a site different from the site used to administer the vaccine.
Because the antibody response following the recommended vaccination regimen with HDCV has been satisfactory, routine post-vaccination serologic testing is not recommended. Serologic testing is indicated in unusual circumstances, as when the patient is known to be immunosuppressed. Contact local or state health department or CDC for recommendations.11
Post-exposure dosage for previously immunized persons:
When an immunized person who was vaccinated using the recommended pre-exposure regimen or a prior post-exposure regimen with a cell culture vaccine or who had previously demonstrated rabies antibody is exposed to rabies, that person should receive two intramuscular doses (1.0 Ml each) of Imovax Rabies vaccine, one dose immediately after the exposure and one dose 3 days later. RIG should not be given in these cases.
If the immune status of a previously vaccinated person who did not receive the recommended HDCV regimen is not known, full primary post-exposure antirabies treatment (RIG plus 5 doses of HDCV) may be necessary. In such cases, if antibody levels of greater than 1:5 dilution by a RFFIT can be demonstrated in a serum sample collected before vaccine is given, treatment can be discontinued after at least two doses of HDCV.20
Imovax Rabies vaccine is supplied in a tamper evident unit dose box with:
One vial of freeze-dried vaccine containing a single dose (NDC 49281-248-58).
One sterile syringe containing diluent (NDC 49281-249-01). A separate plunger is provided for insertion and use.
One sterile disposable needle for reconstitution.
Packaged as NDC 49281-250-51.
The freeze-dried vaccine is stable if stored in the refrigerator between 2°C and 8°C (35°F to 46°F). Do not freeze.
10 CDC. Human rabies despite treatment with rabies immune globulin and human diploid cell rabies vaccine - Thailand. MMWR. 1987 Nov 27;36(46):759-60, 765.
11 Manning SE, Rupprecht CE, Fishbein D, Hanlon CA, Lumlertdacha B, Guerra M, et al. Human rabies prevention - United States 2008: recommendations of the Advisory Committee on Immunization Practices. MMWR. 2008 May 23;57(RR-3):1-28.
12 Rabies vaccines: WHO position paper. Weekly epidemiological record. 2010 Aug 6;85(32):309-320. Available from: http://www.who.int/wer.
18 Cockshott WP, Thompson GT, Howlett LJ, Seely ET. Intramuscular or intralipomatous injections? N Eng J Med. 1982 Aug 5;307(6):356-8.
19 Baer GM, Fishbein DB. Rabies postexposure prophylaxis. N Engl J Med. 1987;316:1270- 72.
20 CDC. Recommendations of the Advisory Committee on Immunization Practices. Human rabies prevention-United States, 1999. MMWR. 1999;48(RR-1):1-21.
Distributed by: Sanofi Pasteur Inc., Swiftwater PA 18370 USA, 1-800-VACCINE (1-800-822-2463). Manufactured by: Sanofi Pasteur SA. Revised: April 2013This monograph has been modified to include the generic and brand name in many instances.
Last reviewed on RxList: 9/19/2014
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