Health Vidya

RabAvert is indicated for preexposure vaccination, in both primary series and booster dose, and for postexposure prophylaxis against rabies in all age groups. Usually an immunization series is initiated and completed with 1 vaccine product. No clinical studies have been conducted that document a change in efficacy or the frequency of adverse reactions when the series is completed with a second vaccine product. However, for booster immunization, RabAvert was shown to elicit protective antibody level responses in persons tested who received a primary series with HDCV.4,11 Preexposure Vaccination: See Table 1 and DOSAGE AND ADMINISTRATION. Preexposure vaccination consists of 3 doses of RabAvert 1.0 mL given intramuscularly (deltoid region), 1 each on Days 0, 7, and 21 or 281 (see also Table 1 for criteria for preexposure vaccination). Preexposure vaccination does not eliminate the need for additional therapy after a known rabies exposure (see DOSAGE AND ADMINISTRATION: Postexposure Prophylaxis of Previously Immunized Persons). Preexposure vaccination should be offered to persons in high-risk groups, such as veterinarians, animal handlers, wildlife officers in areas where animal rabies is enzootic, certain laboratory workers, and persons spending time in foreign countries where rabies is endemic. Persons whose activities 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 preexposure vaccination. International travelers might be candidates for preexposure vaccination if they are likely to come in contact with animals in areas where dog rabies is enzootic and immediate access to appropriate medical care, including biologics, might be limited.27,28 Preexposure vaccination is given for several reasons. First, it may provide protection to persons with inapparent exposure to rabies. Second, it may protect persons whose postexposure therapy might be expected to be delayed. Finally, although it does not eliminate the need for prompt 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. In some instances, booster doses of vaccine should be administered to maintain a serum titer corresponding to at least complete neutralization at a 1:5 serum dilution by the RFFIT (Table 1); each booster immunization consists of a single dose. See CLINICAL PHARMACOLOGY. Serum antibody determinations to decide upon the need for a booster dose is suggested by ACIP and is considered cost effective. Postexposure Treatment: See Table 2 and DOSAGE AND ADMINISTRATION. 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 immunization status of the animal, and presence of rabies in the region (as outlined below). Local or state public health officials should be consulted if questions arise about the need for rabies prophylaxis.1 In the US, the following factors should be considered before antirabies treatment is initiated. Species of Biting Animal: Wild terrestrial animals (especially skunks, raccoons, foxes, and coyotes) and bats are the animals most commonly infected with rabies and are the most important potential source of infection for both humans and domestic animals. Unless a wild animal is tested and shown not to be rabid, postexposure prophylaxis should be initiated upon bite or non-bite exposure to the animals (see definition in “Type of Exposure” below). If treatment has been initiated and subsequent testing in a qualified laboratory shows the exposing animal is not rabid, postexposure prophylaxis can be discontinued.1 The likelihood of rabies in a domestic animal varies from region to region; hence, the need for postexposure prophylaxis also varies.1 Small rodents (such as squirrels, hamsters, guinea pigs, gerbils, chipmunks, rats, and mice) and lagomorphs (including rabbits and hares) are almost never found to be infected with rabies and have not been known to transmit rabies to humans in the US. Bites from large rodents such as woodchucks (including groundhogs) and beavers should be considered as possible rabies exposures, especially in regions where rabies is enzootic in raccoons.30 In all cases involving rodents, the state or local health department should be consulted before a decision is made to initiate antirabies postexposure prophylaxis.1 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. A currently vaccinated dog, cat, or ferret is unlikely to become infected with rabies.1 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. Bites to highly innervated areas such as the face and hands carry the highest risk, but the site of the bite should not influence the decision to begin treatment. Recent epidemiologic data suggest that even the very limited injury inflicted by a bat bite (compared with lesions caused by terrestrial carnivores) should prompt consideration of postexposure prophylaxis unless the bat is available for testing and is negative for evidence of rabies.1 Non-bite: The contamination of open wounds, abrasions, mucous membranes, or theoretically, scratches with saliva or other potentially infectious material (such as neural tissue) from a rabid animal constitutes a non-bite exposure. In all instances of potential human exposures involving bats, and the bat is not available for testing, postexposure prophylaxis might be appropriate even if a bite, scratch, or mucous membrane exposure is not apparent when there is reasonable probability that such exposure might have occurred. Postexposure prophylaxis can be considered for persons who were in the same room as the bat and who might be unaware that a bite or direct contact had occurred (e.g., a sleeping person awakens to find a bat in the room or an adult witnesses a bat in the room with a previously unattended child, mentally disabled person, or intoxicated person) and rabies cannot be ruled out by testing the bat. Other contact by itself, such as petting a rabid animal and contact with blood, urine, or feces (e.g., guano) of a rabid animal, does not constitute an exposure and is not an indication for prophylaxis. Because the rabies virus is inactivated by desiccation and ultraviolet irradiation, in general, if the material containing the virus is dry, the virus can be considered noninfectious. Two cases of rabies have been attributed to probable aerosol exposures in laboratories, and 2 cases of rabies in Texas could possibly have been due to airborne exposures in caves containing millions of bats.1 The only documented cases for rabies from human-to-human transmission occurred in 8 patients, including 2 in the US, who received corneas transplanted from persons who died of rabies undiagnosed at the time of death.1 Stringent guidelines for acceptance of donor corneas have been implemented to reduce this risk. Bite and non-bite exposure from humans with rabies theoretically could transmit rabies, but no laboratory-diagnosed cases occurring under such situations have been documented. Each potential exposure to human rabies should be carefully evaluated to minimize unnecessary rabies prophylaxis.1 Postexposure Treatment Schedule: See also DOSAGE AND ADMINISTRATION. The essential components of rabies