Rationale of treatment
Physicians must evaluate each possible rabies exposure. Local or state public health officials should be consulted if questions arise about the need for prophylaxis.8
In the United States and Canada, the following factors should be considered before antirabies treatment is initiated.
Species of biting animal
Carnivorous wild animals (especially skunks, raccoons, foxes, coyotes, and bobcats) and bats are the animals most commonly infected with rabies and have caused most of the indigenous cases of human rabies in the United States since 1960. Unless an animal is tested and shown not to be rabid, postexposure prophylaxis should be initiated upon bite or nonbite exposure to the animals. (See definition in “Type of Exposure” below.) If treatment has been initiated and subsequent testing in a competent laboratory shows the exposing animal is not rabid, treatment can be discontinued.8
The likelihood that a domestic dog or cat is infected with rabies varies from region to region; hence the need for postexposure prophylaxis also varies.8
Rodents (such as squirrels, hamsters, guinea pigs, gerbils, chipmunks, rats, and mice) and lagomorphs (including rabbits and hares) are rarely found to be infected with rabies and have not been known to cause human rabies in the United States. In these cases, the state or local health department should be consulted before a decision is made to initiate postexposure antirabies prophylaxis.8
Circumstances of biting incident
An UNPROVOKED attack is 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.
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: Any penetration of the skin by teeth.
Nonbite: 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. There have been two instances of airborne rabies acquired in laboratories and two probable airborne rabies cases acquired in a bat-infested cave in Texas.8, 9
The only documented cases for rabies from human-to-human transmission occurred in four patients in the United States and overseas who received corneas transplanted from persons who died of rabies undiagnosed at the time of death.9, 10 Stringent guidelines for acceptance of donor corneas should reduce this risk. Bite and nonbite exposure from humans with rabies theoretically could transmit rabies, although no cases of rabies acquired this way have been documented. Each potential exposure to human rabies should be carefully evaluated to minimize unnecessary rabies prophylaxis.8, 11
Pre- and postexposure treatment of rabies
Pre-exposure - See TABLE 1
Pre-exposure immunization may be offered to persons in high-risk groups, such as veterinarians, animal handlers, certain laboratory workers, and persons spending time (eg, 1 month or more) in foreign countries where rabies is a constant threat. Persons whose vocational or avocational pursuits bring them into contact with potentially rabid dogs, cats, foxes, skunks, bats, or other species at risk of having rabies should also be considered for pre-exposure prophylaxis.8
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 given for several reasons. First, it may provide protection to persons with inapparent exposure to rabies. Secondly, it may protect persons whose postexposure therapy might be expected to be delayed. Finally, although it does not eliminate the need for additional therapy after a rabies exposure, it simplifies therapy by eliminating the need for globulin and decreasing the number of doses of vaccine needed. This is of particular importance for persons at high risk of being exposed in countries where the available rabies immunizing products may carry a higher risk of adverse reactions.
Pre-exposure immunization does not eliminate the need for prompt prophylaxis following an exposure. It only reduces the postexposure treatment regimen.8
Pre-Exposure Rabies Treatment Guide
Pre-exposure immunization: Consists of the three doses of HDCV, 1.0 mL, intramuscularly (deltoid area), one each on Days 0,7 and 21 or 28. Administration of routine booster doses of vaccine depends on exposure risk category as noted in Table 1. Pre-exposure immunization of immunosuppressed persons is not recommended.8
TABLE 18 - CRITERIA FOR PRE-EXPOSURE IMMUNIZATION
|Risk category||Nature of risk||Typical populations||Pre-exposure regimen|
|Continuous||Virus present continuously often in high concentrations. Aerosol, mucous membrane, bite or nonbite exposure possible. Specific exposures may go unrecognized.||Rabies research lab workers.* Rabies biologics production workers.||Primary pre-exposure immunization course. Serology every 6 months. Booster immunization when antibody titer falls below acceptable level.*|
|Frequent||Exposure usually episodic, with source recognized, but exposure may also be unrecognized. Aerosol, mucous membrane, bite or nonbite exposure.||Rabies diagnostic lab workers*, spelunkers, veterinarians, and animal control and wildlife workers in rabies epizootic areas.||Primary pre-exposure immunization course. Booster immunization or serology every 2 years.†|
|Infrequent (greater than population-at-large)||Exposure nearly always episodic with source recognized. Mucous membrane, bite or nonbite exposure.||Veterinarians and animal control and wildlife workers in areas of low rabies endemicity. Certain travelers to foreign rabies epizootic areas. Veterinary students.||Primary pre-exposure immunization course. No routine booster immunization or serology.|
|Rare (population-at-large)||Exposure always episodic, mucous membrane, or bite with source recognized.||US population-at-large, including individuals in rabies epizootic areas.||No pre-exposure immunization.|
|* Judgement of relative risk and extra monitoring
of immunization status of laboratory workers is the responsibility of
the laboratory supervisor (see US Department of Health and Human Service's
Biosafety in Microbiological and Biomedical Laboratories, 1984).
† Pre-exposure booster immunization consists of one dose of HDCV, 1.0 mL/dose, IM (deltoid area). Acceptable antibody level is 1:5 titer (complete inhibition in RFFIT at 1:5 dilution). (See CLINICAL PHARMACOLOGY.) Boost if titer falls below 1:5.
Postexposure - See TABLE 2
The essential components of rabies postexposure prophylaxis are local treatment of wounds and immunization, including administration, in most instances, of both globulin and vaccine (TABLE 2).8, 13
- Local treatment of wounds: Immediate and thorough washing of all
bite wounds and scratches with soap and water is perhaps the most effective
measure for preventing rabies. In experimental animals, simple local wound
cleansing has been shown to reduce markedly the likelihood of rabies.8,
Tetanus prophylaxis and measures to control bacterial infection should be given as indicated.
- Specific treatment: Postexposure antirabies immunization should always include administration of both antibody (preferably RIG) and vaccine, with one exception: persons who have been previously immunized with the recommended pre-exposure or postexposure regimens with HDCV or who have been immunized with other types of vaccines and have a history of documented adequate rabies antibody titer should receive only vaccine. The combination of globulin and vaccine is recommended for both bite exposures and nonbite exposures regardless of the interval between exposure and treatment.14, 15 The sooner treatment is begun after exposure, the better. However, there have been instances in which the decision to begin treatment was made as late as 6 months or longer after the exposure due to delay in recognition that an exposure had occurred.8, 13
- Treatment outside the United States: If postexposure 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 health departments should be contacted for specific advice in such cases.8
Postexposure Treatment 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, and presence of rabies in the region. Local or state public health officials should be consulted if questions arise about the need for rabies prophylaxis.8
|Animal species||Condition ofanimal at time ofattack||Treatment of exposed person*|
Dog and cat
|Healthy and available for 10 days of observation. Rabid or suspected rabid. Unknown (escaped).||None unless animal develops rabies.† RIG§ and HDCV. Consult public health officials. If treatment is indicated, give RIG§ and HDCV.|
Skunk, bat, fox, coyote, raccoon, bobcat and other carnivores
|Regard as rabid unless proven negative by laboratory tests.£||RIG§ and HDCV.|
Livestock, rodents and lagomorphs (rabbits and hares)
|Consider individually. Local and state public health officials should be consulted on questions about the need for rabies prophylaxis. Bites of squirrels, hamsters, guinea pigs, gerbils, chipmunks, rats, mice, other rodents, rabbits and hares, almost never call for antirabies prophylaxis.|
| * All bites and wounds should immediately
be thoroughly cleansed with soap and water. If antirabies treatment is
indicated, both rabies immune globulin (RIG) and human diploid cell rabies
vaccine (HDCV) should be given as soon as possible regardless of the interval
from exposure. Local reactions to vaccines are common and do not contraindicate
continuing treatment. Discontinue vaccine if fluorescent antibody tests
of the animal are negative.
† During the usual holding period of 10 days, begin treatment with RIG and HDCV at first sign of rabies in a dog or cat that has bitten someone. The symptomatic animal should be killed immediately and tested.
§ If RIG is not available, use antirabies serum, equine (ARS). Do not use more than the recommended dosage.
£ The animal should be killed and tested as soon as possible. Holding for observation is not recommended.
DOSAGE AND ADMINISTRATION
Before administration, parenteral drug products should be checked visually for any deviation from normal appearance including container integrity. 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 are observed, the syringe 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 needle for reconstitution. 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. For administration, use a needle of your choice that is suitable for intramuscular injection of your patient.
The 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 HIV (AIDS), HBV, (Hepatitis), and other infectious diseases due to accidental needlesticks, contaminated needles should not be recapped or removed, unless there is no alternative or that such action is required by a specific medical procedure.
The reconstituted vaccine should be used immediately.
After preparation of the injection site, immediately inject the vaccine intramuscularly. For adults and children, the vaccine should be injected into the deltoid muscle.22-27,29 In infants and small children, the mid lateral aspect of the thigh may be preferable. 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.
NOTE: The freeze-dried vaccine is creamy white to orange. After reconstitution it is pink to red.
- Primary vaccination: In the United States, the Advisory Committee on Immunization Practices (ACIP) recommends three injections of 1.0 mL each, one injection on Day 0 and one on Day 7 and one either on Day 21 or 28.8
- Booster dose: Persons working with live rabies virus in research laboratories and in vaccine production facilities should have rabies antibody titers checked every six months and boosters given as needed to maintain an adequate titer. (For definition of adequate titer, see CLINICAL PHARMACOLOGY.) Only laboratory workers, such as those doing rabies diagnostic tests, spelunkers and veterinarians, animal control and wildlife officers in areas where rabies is epizootic should have boosters every 2 years or have their serum tested for rabies antibody every 2 years and, if the titer is inadequate, have a booster dose. Veterinarians and animal control and wildlife officers, if working in areas of low rabies endemicity, do not require routine booster doses of HDCV after completion of primary pre-exposure immunization (TABLE 1.)8
Persons who have experienced “immune complex-like” hypersensitivity reactions should receive no further doses of HDCV 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.
The World Health Organization established a recommendation for six intramuscular doses of human diploid cell vaccine (HDCV) based on studies in Germany and Iran.3, 7 Used in this way, a total of 6 injections of a 1.0 mL dose of vaccine are given according to the following schedule: on Day 0, 3, 7, 14, 30 and 90. The first dose should be accompanied by Rabies Immune Globulin (RIG) or Antirabies Serum (ARS). If possible, up to half the dose of RIG or ARS should be used to infiltrate the wound, and the rest administered intramuscularly, in a different site from the rabies vaccine, preferably in the gluteal region.
Studies conducted at the CDC in the United States have shown that a regimen of 1 dose of Rabies Immune Globulin (RIG) and 5 doses of HDCV induced an excellent antibody response in all recipients. Of 511 persons bitten by proven rabid animals and so treated, none developed rabies.8
Based on these data, the ACIP recommends a 5-dose regimen for postexposure situations. Five 1.0 mL doses are given intramuscularly on Day 0, 3, 7, 14 and 28 in conjunction with RIG on Day 0.8 Because the antibody response following the recommended vaccination regimen with HDCV has been so satisfactory, routine postvaccination serologic testing is not recommended. Serologic testing is indicated in unusual circumstances, as when the patient is known to be immunosuppressed. Contact state health department or CDC for recommendations.8,28
Postexposure therapy of previously immunized persons
When an immunized person who was vaccinated by the recommended 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 HDCV, one immediately and one 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 postexposure antirabies treatment (RIG plus 5 doses of HDCV) may be necessary. In such cases, if antibody can be demonstrated in a serum sample collected before vaccine is given, treatment can be discontinued after at least two doses of HDCV.8
IMOVAX RABIES VACCINE is supplied in a tamper evident unit dose box with:
- One vial of freeze-dried vaccine containing a single dose.
- One syringe containing diluent. A separate plunger is provided for insertion and use.
- One disposable needle for reconstitution.
Product No. 49281-250-51
“CPT ® Code: 90675 CPT is a registered trademark of the American Medical Association”
The freeze-dried vaccine is stable if stored in the refrigerator at 2°C to 8°C (35°F to 46°F). Do not freeze.
8. CDC. Recommendations of the Immunization Practices Advisory Committee (ACIP). Rabies Prevention—United States, 1984, MMWR 33: 393-402, 407-8 (1984).
9. Anderson LJ, Nicholson KG, Tauxe RV, Winkler WG. Human rabies in the United States, 1960 to 1979, epidemiology, diagnosis and prevention. Ann Intern Med 100: 728-35 (1984).
10. WHO. Sixth report of the Expert Committee on Rabies. Geneva Switzerland: World Health Organization. (WHO technical report No. 523) (1973).
11. Baer GM, ed. The natural history of rabies. New York: Academic Press. (1975).
13. Helmick CG. The epidemiology of human rabies postexposure prophylaxis. JAMA 250:1990-6 (1983).
14. Devriendt J, Staroukine M, Costy F, Vanderhaegen J-J. Fatal encephalitis apparently due to rabies. JAMA 248: 2304-6 (1982).
15. CDC. Human Rabies—Rwanda. MMWR 31: 135 (1982).
22. Cockshott WP, Thompson GT, Howlett LJ, Seely ET. Intramuscular or intralipomatous injections? N Eng J Med 307: 356-58 (1982).
23. CDC. General Recommendations on Immunization, ACIP. MMWR 32: 1-8, 13-17 (1983).
24. Committee on Immunization Council of Medical Societies, American College of Physicians. Guide for Adult Immunizations. (1985).
25. CDC. Rabies postexposure prophylaxis with HDCV: Lower neutralizing antibody titers with Wyeth vaccine. MMWR 34: 90-92 (1985).
26. Shill M, Baynes RD, Miller SD. Fatal rabies encephalitis despite appropriate postexposure prophylaxis. N Engl J Med 316: 1257-58 (1987).
27. Baer GM, Fishbein DB. Rabies postexposure prophylaxis. N Engl J Med 316: 1270-72 (1987).
28. CDC. Recommendations of the Immunization Practices Advisory Committee (ACIP). Supplementary statement on rabies vaccine and serologic testing. MMWR 30: 535-6 (1981).
29. CDC. Human rabies despite treatment with Rabies Immune Globulin and Human Diploid Cell Rabies Vaccine - Thailand. MMWR 36: 759-765 (1987).
Product information as of December 2005. Manufactured by: Sanofi Pasteur SA, Lyon France. Distributed by: Sanofi Pasteur Inc., Swiftwater PA 18370 USA. 1-800-VACCINE (1-800-822-2463). FDA revision date: n/a
Last reviewed on RxList: 11/10/2008
This monograph has been modified to include the generic and brand name in many instances.
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