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Imogam Rabies

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Imogam Rabies


Rabies Immune Globulin (Human), Imogam® Rabies - HT (rabies immune globulin (human)) , is indicated for individuals suspected of exposure to rabies, particularly severe exposure, with one exception: persons who have been previously immunized with HDCV Rabies Vaccine in a pre-exposure or postexposure treatment series should receive only vaccine. Persons who have received Rabies Vaccines other than HDCV, RVA (Rabies Vaccine Adsorbed) or PCEC (Purified Chick Embryo Cell Vaccine) vaccines should have confirmed adequate rabies antibody titers if they are to receive only vaccine. 1

Imogam® Rabies - HT (rabies immune globulin (human)) should be injected as promptly as possible after exposure along with the first dose of vaccine. If initiation of treatment is delayed for any reason, Imogam® Rabies - HT (rabies immune globulin (human)) and the first dose of vaccine should still be given, regardless of the interval between exposure and treatment. Imogam® Rabies - HT may be given up to eight days after the first dose of vaccine was given.

Rabies virus is usually transmitted by the bite of a rabid animal (dog, bat, etc. ) but can occasionally penetrate abraded skin contaminated with the saliva of infected animals. Progress of the virus after exposure is believed to follow a neural pathway and the time between exposure and clinical rabies is a function of the proximity of the bite (or abrasion) to the central nervous system and the dose of virus injected. The incubation is usually 2 to 6 weeks but can be longer. After severe bites about the face and neck and arms, it may be as short as 10 days. After initiation of the vaccine series (human diploid cell origin), it takes approximately one week for development of immunity to rabies; therefore, the value of immediate passive immunization with rabies antibodies in the form of Rabies Immune Globulin (Human) cannot be overemphasized.

Recommendations for passive and/or active immunization after exposure to an animal suspected of having rabies have been outlined by the WHO29 and by the United States Public Health Service Advisory Committee on Immunization Practices (ACIP). 1

Rationale of Treatment

In the United States and Canada the following factors should be considered before specific antirabies treatment is indicated:

Species of Biting Animal

Carnivorous animals (especially skunks, foxes, coyotes, raccoons, dogs, bobcats, and cats) and bats are more likely to be infected with rabies than other animals. Rats, mice, squirrels, hamsters, guinea pigs, gerbils, chipmunks and other rodents or rabbits and hares are rarely infected with rabies and have not been known to cause human rabies in the United States. Their bites almost never call for antirabies prophylaxis; therefore, before initiating antirabies prophylaxis, the local or state health department should be consulted.

Because some bat bites may be less severe, and therefore more difficult to recognize, than bites inflicted by larger mammalian carnivores, rabies postexposure treatment should be considered for any physical contact with bats when bite or mucous membrane contact cannot be excluded. 1, 30, 31

Circumstances of Biting Incident

An UNPROVOKED attack is more likely than a provoked attack to indicate that 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 commonly transmitted by inoculation with infectious saliva. The likelihood that rabies infection will result from exposure to a rabid animal varies with the nature and extent of the 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.

In addition, two cases of rabies have been attributed to airborne exposures in laboratories and two cases of rabies have been attributed to probable exposures to a bat-infested cave (Frio Cave, Texas). 1, 32-34 Casual contact with a rabid animal, such as petting the animal (without a bite or nonbite exposure as described above) does not constitute an exposure and is not an indication for prophylaxis.

The only documented cases of rabies due to human-to-human transmission occurred in patients who received corneas transplanted from persons who died of rabies undiagnosed at the time of death. 1, 35

Each exposure to possible rabies infection must be individually evaluated. Local or state public health officials should be consulted if questions arise about the need for rabies prophylaxis.

Vaccination Status of Biting Animal

A properly immunized animal has only a minimal chance of developing rabies and transmitting the virus.

Postexposure Treatment of Rabies

Local Treatment of Wounds

Immediate and thorough local treatment of all bite wounds and scratches is perhaps the most effective preventive measure. The wound should be thoroughly cleansed immediately with soap and water. Tetanus prophylaxis and measures to control bacterial infection should be given as indicated.

Specific Treatment

Postexposure antirabies treatment should always include both passive (preferably Rabies Immune Globulin - Human) and active (preferably Rabies Vaccine prepared from human diploid cells) immunization with one exception: persons who have been previously immunized with HDCV Rabies Vaccine in a pre-exposure or postexposure treatment series should receive only vaccine. Persons who have received Rabies Vaccines other than HDCV, RVA or PCEC vaccines should have confirmed adequate rabies antibody titers if they are to receive only vaccine. 1 The combination of globulin and vaccine is recommended for both bite exposures and nonbite exposures (as described under "Rationale of Treatment") and regardless of the interval between exposure and treatment. The sooner treatment is begun after exposure, the better.

Postexposure Treatment Guide

The following recommendations are only a guide. They should be applied in conjunction with knowledge of the animal species involved, circumstances of the bite or other exposure, vaccination status of the animal, and presence of rabies in the region. Local and state public health officials should be consulted if questions arise about the need for rabies prophylaxis.


Animal Type Evaluation and Disposition of Animal Postexposure Prophylaxis Recommendations
Dogs, cats, and ferrets Healthy and available for 10 days observation Persons should not begin prophylaxis unless animal develops clinical signs of rabies. *
Rabid or suspected rabid Immediately vaccinate.
Unknown (e. g. escaped) Consult public health officials.
Skunks, raccoons, foxes, and most other carnivores; bats Regarded as rabid unless animal proven negative by laboratory tests Consider immediate vaccination
Livestock, small rodents, lagomorphs (rabbits and hares), large rodents (woodchucks and beavers), and other mammals Consider individually Consult public health officials. Bites of squirrels, hamsters, guinea pigs, gerbils, chipmunks, rats, mice, other small rodents, rabbits, and hares almost never require antirabies postexposure prophylaxis
*During the 10-day observation period, begin postexposure 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.
The animal should be euthanized and tested as soon as possible. Holding for observation is not recommended. Discontinue vaccine if immunofluorescence test results of the animal are negative.


Parenteral drug products should be inspected visually for particulate matter and/or discoloration prior to administration, whenever solution and container permit. If either of these conditions exist, the vaccine should not be administered.

Imogam® Rabies - HT (rabies immune globulin (human)) should be used in conjunction with Rabies Vaccine such as Rabies Vaccine Imovax® Rabies, for intramuscular immunization, vaccine prepared from human diploid cell cultures. The recommended dose of Imogam® Rabies - HT is 20 IU/kg (0. 133 mL/kg) or 9 IU/lb (0. 06 mL/lb) of body weight administered at time of the first vaccine dose. 25, 26, 43 The gluteal area should never be used for HDCV, RVA, or PCEC injections because administration of HDCV in this area results in lower neutralizing antibody titers. 1, 43, 44 If anatomically feasible, the full dose of Rabies Immune Globulin (Human) (RIG) should be thoroughly infiltrated in the area around and into the wounds. Any remaining volume should be injected intramuscularly at a site distant from vaccine administration. 1 Two injections would be given in the gluteal muscle if the volume is greater than 5 mL.

Human Rabies Immune Globulin (HRIG) should never be administered in the same syringe or into the same anatomical site as vaccine. Because HRIG may partially suppress active production of antibody, no more than the recommended dose should be given. 1, 27


Imogam® Rabies - HT (rabies immune globulin (human)) is supplied in 2 mL and 10 mL vials with minimal potency of 150 International Units per milliliter (IU/mL).

Vial, 2 mL contains 300 IU which is sufficient for a child weighing 15 kg (33 lb). Product No. 49281-190-20.

Vial, 10 mL contains a total of 1, 500 IU which is sufficient for an adult weighing 75 kg (165 lb). Product No. 49281-190-10


Imogam® Rabies - HT (rabies immune globulin (human)) should be stored in the refrigerator between 2° and 8°C (35° and 46°F). Do not freeze.



1. Recommendation of the Advisory Committee on Immunization Practices (ACIP). Human Rabies prevention - United States, 1999. MMWR 48:No. RR-1, 1999

25. Cabasso VJ, et al. Rabies immune globulin of human origin: preparation and dosage determination in non-exposed volunteer subjects. Bull WHO 45:303-315, 1971

26. Loofbourow JC, et al. Rabies immune globulin (human). Clinical trials and dose determination. JAMA 217:1825-1831, 1971

27. Helmick CG, et al. A clinical study of Mérieux human rabies immune globulin. J Biol Stand 10:357-367, 1982

29. WHO Expert Committee on Rabies. WHO Tech Rep Ser 523:50-51, 1973

30. ACIP. Human Rabies - California, 1994. MMWR 43:455-457, 1994

31. Wilde H, et al. Failure of Postexposure Treatment of Rabies in Children. Clin Infect Dis 22:228-232, 1996

32. Afshar A. A review of non-bite transmission of rabies virus infection. Br Vet J 135:142-148, 1979

33. Winkler WG, et al. Airborne rabies transmission in a laboratory worker. JAMA 226:1219-1221, 1973

34. CDC. Rabies in a laboratory worker - New York. MMWR 26:183-184, 1977

35. Gode GR, et al. Two rabies deaths after corneal grafts from one donor {letter}. Lancet 2:791, 1988

43. World Health Organization. WHO expert committee on rabies. WHO Tech Rep Ser 824:1992

44. Fishbein DB, et al. Administration of human diploid-cell rabies vaccine in the gluteal area. N Engl J Med 318:124-125, 1988

Manufactured by: Aventis Pasteur SA, Lyon, France. Distributed by: Aventis Pasteur Inc. Swiftwater PA 18370, USA. 1-800-VACCINE (1-800-822-2463) FDA Rev date: n/a

Last reviewed on RxList: 10/23/2008
This monograph has been modified to include the generic and brand name in many instances.


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