Criteria for application withholding of post-exposure treatment
The combination of local treatment of the wound, passive immunization with rabies immunoglobulins (RIG) and vaccination is recommended for all severe exposures (category III) to rabies. Prompt and thorough cleansing of the wound, and administration of purified equine or human rabies immunoglobulins (ERIG or HRIG) and cell-culture rabies vaccine immediately after exposure virtually guarantee complete protection, and the risk of post-exposure treatment complications is much lower than with brain-tissue vaccines. Pregnancy and infancy are never contraindications to post-exposure rabies vaccination. Since prolonged incubation periods have been noted, persons who present for evaluation and treatment even months after having been bitten should be dealt with in the same manner as if the contact occurred recently.
Factors that should be considered in deciding whether or not to initiate post-exposure treatment are:
- the nature of the contact
- the presence of rabies in the area where the contact occurred or from which the animal involved came
- the species of the animal involved
- the vaccination and clinical status of the animal involved, the type of vaccine used and the availability of the animal for observation
- the results of laboratory testing of the animal for rabies, if available
An apparently healthy dog or cat that bites a person may or may not justify the initiation of treatment, depending on the perceived risk. If the animal involved is a recognized rabies vector in the area where the contact occurred, initiation of treatment should never await the results of laboratory diagnosis. If the animal is suspected of being rabid, immediate euthanasia and laboratory examination of the brain should be performed. Wound treatment must be completed and serum and vaccine therapy instituted as soon as possible after any exposure. If the species involved is unlikely to be infected with rabies, treatment may be deferred pending the outcome of laboratory testing provided that diagnosis can be made within 48 hours. A report from a reliable laboratory indicating a negative result usually justifies cessation of treatment.
If the animal involved is a dog or cat, it should be kept under observation, preferably under veterinary supervision, for 10 days. Treatment may be discontinued if the dog or cat remains healthy during this period. The eighth report of the WHO Expert Committee suggested, however, that people in contact with animals other than cats and dogs that are suspected of being rabid should receive full post-exposure treatment unless the animal is available and can be killed humanely and examined for rabies in a reliable laboratory immediately.