Rabies Post-Exposure Prophylaxis — Exposure Categories, Vaccine Schedules, RIG and Re-exposure

Rabies is a viral zoonosis of the central nervous system. Dogs cause up to 99% of human cases, and once symptoms appear rabies is virtually 100% fatal (WHO). Yet it is entirely preventable if post-exposure prophylaxis (PEP) is given before the virus reaches the brain. The incubation period is typically 2–3 months but ranges from about a week to a year, depending on the site of entry and viral load — which is why PEP is started at once, however late the patient presents.

In India, the 2019 national guidelines quote estimates of about 17.4 million (174 lakh) animal bites and about 20,000 rabies deaths every year. WHO notes that about 40% of rabies deaths are in children under 15. PEP has three parts: thorough wound washing, a course of rabies vaccine and, when indicated, rabies immunoglobulin (RIG) or rabies monoclonal antibodies (RmAb).

1. Wash immediately — flush all wounds with soap and running water for 15 minutes. This mechanically removes virus and is the single most useful first-aid step; it is worth doing even if the patient presents late, as long as the wound is unhealed.
2. Apply a virucidal antiseptic after drying — povidone-iodine or alcohol.
3. Do not touch the wound with bare hands and do not apply irritants such as soil, chillies, oil, lime, turmeric or herbs — if applied, wash them off gently with soap and water.
4. Avoid suturing. If it cannot be avoided, infiltrate RIG first and delay minimal suturing by several hours to let RIG diffuse. Severe wounds are managed with daily dressing and secondary suturing.
5. Tetanus prophylaxis as per national guidelines, and antibiotics if needed to prevent wound sepsis.

Only cell culture or embryonated egg-based vaccines are used, each with a potency of at least 2.5 IU per IM dose. The same vaccine is used intradermally at 0.1 ml per site, whatever the reconstituted volume. Day 0 is the day the first dose is given. The NRCP strongly advocates the intradermal route because it saves vaccine; WHO estimates ID use cuts costs by 60–80% without loss of safety or efficacy.

• Site: IM into the deltoid; anterolateral thigh in infants and small children. Never the gluteal region — fat delays absorption and impairs the immune response.
• ID route is not preferred in immunocompromised people or those on chloroquine, hydroxychloroquine, long-term steroids or other immunosuppressants — they get the IM course.
• Switching between ID and IM routes or between vaccine brands during a course is not recommended routinely.
• A reconstituted vial must be used within 6 hours (kept at 2–8°C).
• No contraindication to PEP — including pregnancy and breastfeeding, given rabies' fatality.

RIG provides ready-made neutralising antibody at the wound until the patient's own antibodies appear after vaccination. It is given to all category III exposures (and category II in the immunocompromised), except those who have previously completed PrEP or PEP.

• Infiltrate the whole dose, or as much as anatomically possible, into and around the wounds; give any remainder IM at a site distant from the vaccine.
• Fingertips, toes, ear lobes, nose and genitalia can be infiltrated, avoiding excessive pressure.
• Give RIG once, at or as soon as possible after the first vaccine dose. It is not indicated beyond day 7 after the first dose, because the active antibody response has begun and RIG could blunt it.

• High-risk groups: laboratory staff handling rabies virus, clinicians and others attending human rabies cases; veterinarians, animal handlers and dog catchers; wildlife wardens and quarantine officers; travellers from rabies-free to endemic areas.
• Children: the Indian Academy of Pediatrics recommends PrEP, which may be offered on a voluntary basis.

High-risk workers should have neutralising antibody titres checked every 6 months for the first 2 years, then every 2 years; a booster is given only if the titre falls below 0.5 IU/ml. PrEP does not replace PEP — a vaccinated person who is exposed still needs wound care and booster doses, but no RIG.

For where rabies vaccine sits among India's programmes see national health programmes and the national immunisation schedule; for how prophylaxis fits the prevention framework see levels of prevention. Serum sickness after ERIG is a type III reaction — see hypersensitivity reactions.