Rabies Post Exposure Prophylaxis — Wounds and Vaccination

Key Points

• Clinical rabies is nearly always fatal, so prevention must occur before symptoms begin.
• Wash potential rabies wounds immediately and thoroughly with soap and water.
• PEP decisions depend on the exposure, animal species, local epidemiology, testing or observation availability, and prior vaccination status.
• Previously unvaccinated patients receive vaccine plus HRIG; previously vaccinated patients receive vaccine only.
• HRIG dose is 20 IU/kg for all age groups and should be infiltrated into and around wounds as much as anatomically feasible.
• Immunocompetent patients who were not previously vaccinated receive vaccine on days 0, 3, 7, and 14.
• Immunocompromised patients require an additional day 28 dose and follow-up serology according to CDC guidance.
• Do not inject rabies vaccine in the gluteal region.
• Public health consultation is appropriate when animal testing, observation, or epidemiologic risk is uncertain.

Algorithm

1. Identify whether saliva or neural tissue contacted broken skin or a mucous membrane.
2. Determine animal species, behavior, vaccination status when known, geographic rabies epidemiology, and whether the animal is available for testing or observation.
3. Immediately cleanse and irrigate all wounds; address tetanus prophylaxis, bacterial infection risk, and structural injury.
4. If the exposure is judged to warrant PEP, determine whether the patient was previously vaccinated against rabies.
5. If not previously vaccinated, give HRIG 20 IU/kg once, infiltrating wounds first, plus vaccine on day 0.
6. Continue vaccine on days 3, 7, and 14; add day 28 for immunocompromised patients.
7. If previously vaccinated, omit HRIG and give vaccine on days 0 and 3.
8. Coordinate animal observation or testing and any schedule deviations with public health authorities.
9. Document biologic product, lot, dose, route, site, and the dates of all planned doses.

Clinical Synopsis & Reasoning

Rabies exposure assessment begins by deciding whether infectious saliva or neural tissue could have contacted broken skin or a mucous membrane. A bite that penetrates the skin is the classic exposure, but scratches contaminated with saliva and saliva contact with the eyes, mouth, or an open wound can also transmit virus. Touching an animal, contact with blood, urine, or feces, and saliva contact with intact skin are not rabies exposures. Bat encounters deserve special attention because small bites can be difficult to recognize. Public health consultation is valuable when the exposure history, local animal epidemiology, or disposition of the animal is uncertain.

The species and circumstances materially change risk. In the United States, bats are the leading source of human rabies, and raccoons, skunks, and foxes remain important terrestrial reservoirs in many regions. Healthy dogs, cats, and ferrets that bite a person can often be observed for 10 days under public health or veterinary supervision rather than being euthanized immediately. Wild terrestrial carnivores and bats generally require testing when available, and postexposure prophylaxis should not be delayed when a high-risk animal is unavailable for testing. International exposures require country-specific risk assessment because canine rabies remains endemic in many parts of the world.

Once a meaningful exposure is identified, prophylaxis is highly effective when given before symptoms develop. The patient does not need to wait for symptoms, antibody testing, or routine laboratory studies. The core tasks are vigorous wound cleansing, appropriate rabies immune globulin for people not previously vaccinated, and vaccine on the correct schedule. The clinician should also address tetanus status, bacterial wound infection risk, and structural injury from the bite. Rabies biologics are prevention tools, not treatment for established symptomatic rabies.

Treatment Strategy & Disposition

Immediately wash and flush all bite and scratch wounds with soap and copious water. Irrigation is one of the most important components of rabies prevention because it mechanically reduces inoculated virus. A virucidal agent such as povidone-iodine can be used after washing when available. Debridement and closure decisions should follow normal wound principles, but if primary closure is necessary, human rabies immune globulin should first be infiltrated into and around the wound whenever feasible.

For a person who has never completed an accepted rabies vaccination series, administer human rabies immune globulin once at 20 IU/kg. Infiltrate as much of the calculated dose as anatomically feasible into and around all wounds. Any remaining volume is given intramuscularly at a site distant from vaccine administration. Do not exceed the weight-based dose because excessive passive antibody can blunt the active vaccine response. HRIG is ideally given on day 0, but it can generally be given through day 7 after the first vaccine dose if it was omitted initially. It should not be given after day 7 because endogenous antibody production is expected to be developing.

For immunocompetent, previously unvaccinated patients, rabies vaccine is given intramuscularly on days 0, 3, 7, and 14. Immunocompromised patients receive an additional dose on day 28 and should have postvaccination serologic assessment according to CDC guidance. People previously vaccinated with an accepted regimen receive vaccine on days 0 and 3 only and should not receive HRIG. Vaccine is administered in the deltoid in adults; in small children, the anterolateral thigh is acceptable. It should not be injected in the gluteal area because immune response can be unreliable. When the schedule is interrupted by a short delay, the series is usually resumed rather than restarted. Significant deviations or unusual prior vaccine histories should be discussed with public health authorities.

Epidemiology / Risk Factors

• Rabies is maintained in wildlife reservoirs in the United States, particularly bats and several terrestrial carnivores.
• Globally, dog-mediated rabies remains a major cause of human deaths in endemic regions.
• Human-to-human transmission is extraordinarily rare and has been associated mainly with transplanted organs or tissues.
• Incubation is usually weeks to months but is variable, which is why PEP remains useful after delayed presentation before symptoms begin.
• Once encephalitic or paralytic rabies becomes clinically apparent, survival is exceptional.

Investigations

Who Gets What

Pharmacology

Prognosis / Complications

• Appropriately administered PEP before symptom onset is highly effective at preventing rabies.
• Failure is rare in the United States when wound care, HRIG, and vaccine are given correctly.
• Risk of failure rises with incomplete wound infiltration, major schedule errors, immunosuppression, or use of inadequate biologics.
• Symptomatic rabies carries an extremely poor prognosis despite intensive care.
• Completion of the full recommended regimen is essential even if the wound has healed.

Patient Education / Counseling

• Explain why treatment is preventive and should not wait for symptoms.
• Review the full vaccine schedule before discharge and provide written dates for future doses.
• Advise the patient to contact public health or the treating facility if a scheduled dose will be delayed.
• Explain expected local vaccine reactions and that mild reactions are not a reason to stop PEP.
• Tell patients to return for fever, spreading redness, purulent drainage, neurovascular symptoms, or other bite-wound complications.
• Discuss animal observation or test results and how those results may change the need for continued PEP only under public health guidance.

Notes

Rabies prophylaxis is best treated as a coordinated public health intervention rather than a routine vaccine prescription. The exposure itself determines whether PEP is warranted, and local epidemiology can substantially alter the decision. When the animal is available, testing or observation may prevent unnecessary treatment, but high-risk exposures should not be left untreated while waiting for an animal that is unlikely to be recovered.

The most common technical error is giving HRIG only intramuscularly rather than infiltrating the wound. The purpose of HRIG is to neutralize virus locally before vaccine-induced immunity develops, so wound infiltration is the priority. Another important error is giving HRIG to a previously vaccinated patient, which provides no benefit and can interfere with active immunity.

References

1. CDC Rabies Post-exposure Prophylaxis Guidance — Link
2. CDC Rabies Biologics — Link
3. CDC Yellow Book: Rabies — Link