Rabies Immunoglobulin (RIG) - Dose

Key Rules of Administration

1. Given only ONCE - on Day 0, at the time of (or as soon as possible after) initiating post-exposure vaccination.
2. Time limit: Must NOT be given beyond Day 7 after the first vaccine dose, because active antibody production is presumed to have started by then. Giving RIG after Day 7 may interfere with active immunity.
3. Route and site:
   • As much of the dose as anatomically possible should be infiltrated directly into and around the wound site(s)
   • Any remaining dose is injected intramuscularly at a site distant from the vaccine injection site (not in the same limb as the vaccine)
   • Avoid the gluteal region for vaccine injection
4. Volume adjustment: RIG may be diluted in normal saline to ensure sufficient volume to infiltrate all wounds.
5. Not indicated if previously vaccinated: Patients with documented prior complete vaccination (pre- or post-exposure) do not need RIG.

Indications (WHO Exposure Categories)

Special Notes

• ERIG anaphylaxis risk: ~1 in 45,000 cases. Skin testing before ERIG is not recommended (does not predict reactions) - the physician should be prepared to manage anaphylaxis.
• Immunocompromised patients (including HIV/AIDS): Require full 5-dose IM vaccine series + RIG for Category II and III exposures.
• HRIG and ERIG have shown similar clinical outcomes in preventing rabies, but ERIG is considerably less expensive.

Complete Rabies Vaccine Regimens (CCEEV/CVV)

A. Post-Exposure Prophylaxis (PEP) - Intramuscular (IM) Regimens

1. Essen Regimen (5-dose) - Classic WHO Standard

• Most widely used globally
• RIG given on Day 0 only

2. Zagreb Regimen (2-1-1) - Abbreviated Multisite IM

• 2 doses given simultaneously on Day 0 (one in each deltoid or thigh)
• Fewer visits, fewer vials - better compliance
• RIG given on Day 0

3. 4-Dose Essen Regimen (ACIP / Shortened)

• For healthy, fully immunocompetent patients who receive wound care + high-quality RIG + WHO-prequalified vaccine
• Shorter course; not for immunocompromised

B. Post-Exposure Prophylaxis - Intradermal (ID) Regimen

2-Site Intradermal Regimen (2+2+2+0+2) - Updated Thai Red Cross

• Requires only 1-2 vials total for full course
• 60-80% less vaccine than IM routes - major cost saving
• Equally safe and efficacious as IM
• Contraindication: Patients on chloroquine should NOT receive ID rabies vaccine (reduced response) - give IM instead
• Only in countries where ID route is endorsed by national health authorities

WHO Recommended 1-Week ID Regimen (2018 update)

• Shortest WHO-approved PEP schedule
• For resource-limited or high-throughput settings

C. Pre-Exposure Prophylaxis (PrEP)

• RIG is NOT given with PrEP
• Boosters: Not routinely needed. Recommended only for those at continual/frequent occupational risk
  • Antibody test every 6 months for lab workers with high virus exposure
  • Antibody test every 2 years for veterinarians/animal health officers
  • Booster only if neutralizing antibody titre falls to <0.5 IU/ml

D. PEP for Previously Vaccinated Individuals

• No RIG needed
• Abbreviated schedule: 1 IM dose on Days 0 and 3 only (2 visits)
• Alternative: Single-visit 4-site ID regimen (4 × 0.1 ml on Day 0 over deltoids/thighs)
• Applies if prior complete PrEP or PEP with CCEEV is documented, OR if neutralizing antibody titre ≥ 0.5 IU/ml

E. Immunocompromised Patients (incl. HIV/AIDS)

• Full 5-dose IM Essen regimen (Days 0, 3, 7, 14, 28)
• Plus RIG for Category II & III exposures
• Assess antibody response 2-4 weeks post-vaccination; additional dose may be needed

Quick Summary Table

Rabies - NEET PG & AMC Previous Year / High-Yield MCQs

Q1. (NEET PG / AMC repeat)

• A) 10 IU/kg
• B) 20 IU/kg ✅
• C) 40 IU/kg
• D) 60 IU/kg

Answer: B - 20 IU/kg ERIG/F(ab')2 = 40 IU/kg. HRIG = 20 IU/kg. This is the single most tested fact on rabies immunoglobulin.

Q2. (AMC / NEET PG)

• A) 20 IU/kg
• B) 30 IU/kg
• C) 40 IU/kg ✅
• D) 80 IU/kg

Answer: C - 40 IU/kg ERIG is twice the dose of HRIG because equine antibodies are less efficiently distributed.

Q3. (NEET PG 2018 pattern)

• A) Day 3
• B) Day 5
• C) Day 7 ✅
• D) Day 14

Answer: C - Day 7 After day 7, active antibody production from the vaccine is presumed to have begun. RIG given later may interfere with this response.

Q4. (AMC / NEET PG)

• A) Only IM in the gluteal region
• B) Infiltrated into the wound; remainder IM at a site distant from vaccine ✅
• C) Only at the vaccine injection site
• D) IV infusion

Answer: B Maximum volume infiltrated around the wound; any remainder given IM at a site distant from the vaccine injection site.

Q5. (NEET PG 2019-type)

• A) Days 0, 3, 7, 14, 28 (5 doses)
• B) Days 0 (×2 sites), 7, 21 (4 doses) ✅
• C) Days 0, 3, 7 only (3 doses)
• D) Days 0, 7, 21, 28 (4 doses)

Answer: B Zagreb (2-1-1) = 2 doses on Day 0 (one in each deltoid/thigh), then 1 dose each on Day 7 and Day 21. Total: 4 vials, 3 visits.

Q6. (NEET PG / AMC classic)

• A) 3 doses on days 0, 7, 21
• B) 4 doses on days 0, 3, 7, 14
• C) 5 doses on days 0, 3, 7, 14, 28 ✅
• D) 6 doses on days 0, 1, 2, 7, 14, 28

Answer: C Essen = 5 doses, IM, days 0, 3, 7, 14, 28 - the WHO standard regimen.

Q7. (AMC / NEET PG)

• A) Full 5-dose Essen regimen + RIG
• B) Wound care alone, no vaccine needed
• C) 2 doses IM on Days 0 and 3, no RIG ✅
• D) 4 doses IM on Days 0, 3, 7, 14 + RIG

Answer: C Previously vaccinated individuals need only 2 booster doses (Day 0 and Day 3). RIG is NOT indicated.

Q8. (AMC style)

• A) Each ID dose is 1.0 ml
• B) It uses 60-80% MORE vaccine than IM
• C) Patients on chloroquine should receive ID instead of IM vaccine
• D) Each ID dose is 0.1 ml, saving 60-80% vaccine volume ✅

Answer: D ID dose = 0.1 ml per site. This saves 60-80% vaccine volume. Chloroquine reduces ID vaccine response - these patients should receive IM, not ID.

Q9. (NEET PG 2020-type)

• A) Category I only
• B) Category II only
• C) Category III ✅
• D) Categories I and II

Answer: C - Category III Cat I = no treatment; Cat II = vaccine only; Cat III (transdermal bites, licks on broken skin, bat contact) = vaccine + RIG.

Q10. (AMC / NEET PG)

• A) Intradermal ✅ - WRONG
• B) Intramuscular ✅
• C) Subcutaneous
• D) Intravenous

Answer: B - Intramuscular Chloroquine impairs the immune response to intradermal rabies vaccination. These patients must receive the vaccine IM, not ID.

Q11. (NEET PG)

• A) Days 0, 3, 7, 14, 28
• B) Days 0, 7, 21 or 28 ✅
• C) Days 0, 3, 7 only
• D) Single dose annually

Answer: B - Days 0, 7, and 21 or 28 PrEP = 3 doses on days 0, 7, and 21/28. No RIG is used.

Q12. (AMC / NEET PG)

• A) 1 in 100
• B) 1 in 1,000
• C) 1 in 45,000 ✅
• D) 1 in 1,00,000

Answer: C - 1 in 45,000 Skin testing before ERIG is NOT recommended as it does not predict anaphylaxis.

Q13. (NEET PG high-yield)

• A) 4-dose Essen regimen, no RIG
• B) Zagreb 2-1-1 regimen + RIG
• C) Full 5-dose Essen regimen (IM) + RIG ✅
• D) 2 doses on Days 0 and 3, no RIG

Answer: C Immunocompromised patients always get the full 5-dose IM regimen + RIG. Antibody titres should be checked at 2-4 weeks.

Q14. (AMC Classic)

• A) 1994
• B) 1999
• C) 2004 ✅
• D) 2010

Answer: C - 2004 India discontinued NTV in 2004; replaced by safer, more effective cell-culture vaccines.

Key Memory Table for Exam Day

Rabies - NEET PG / FMGE / INICET Actual PYQs

PSM / Community Medicine

• A) Mass vaccination of humans
• B) Mass vaccination of stray dogs ✅
• C) Culling of stray dogs
• D) Post-exposure prophylaxis for all bite victims

Answer: B - Mass vaccination of stray dogs Dogs are responsible for >90% of human rabies deaths in developing countries. Dog rabies control is the most cost-effective strategy.

• A) Days 0, 3, 7
• B) Days 0, 7, 14
• C) Days 0, 7, 28 ✅
• D) Days 0, 3, 7, 14, 21

Answer: C - Days 0, 7, 28 PrEP = 3 doses of HDCV/CCEEV on days 0, 7 and 28 (or 21). 1 ml IM or 0.1 ml ID.

• A) 1
• B) 2
• C) 3 ✅
• D) 4

Answer: C - 3 doses Days 0, 7, and 28. One month after the 3rd injection, serum antibody titres are checked. If titre < 0.5 IU/ml, booster doses are given.

• A) Bite
• B) Lick on abraded skin
• C) Aerosol (bat caves)
• D) Ingestion of products from infected animals ✅

Answer: D - Ingestion Routes of transmission: animal bites, licks on abraded skin/mucosa, aerosol (bat caves), person-to-person (corneal/organ transplant). Ingestion is NOT a recognized route.

• A) Person-to-person transmission (corneal transplant)
• B) Aerosol
• C) Ingestion of products made from infected animals ✅
• D) Licks on broken skin

Answer: C Same concept - ingestion is not a route. Aerosol transmission can occur in bat caves.

• A) Guarner bodies
• B) Negri bodies ✅
• C) Cowdry A bodies
• D) Cowdry B bodies

Answer: B - Negri bodies Negri bodies = intracytoplasmic inclusion bodies in neurons of the brain (especially Purkinje cells of cerebellum and hippocampus). Composed of fibrillar matrix + virus particles. Also found in corneal imprints.

• A) Active immunity
• B) Passive immunity ✅
• C) Humoral immunity
• D) Cellular immunity

Answer: B - Passive immunity RIG provides ready-made antibodies = passive immunity. Vaccine provides active immunity.

• A) MMR ✅
• B) Rabies vaccine
• C) Hepatitis B vaccine
• D) None of the above

Answer: A - MMR Rabies and Hepatitis B are killed/inactivated vaccines - safe in pregnancy. MMR is a live attenuated vaccine - contraindicated in pregnancy due to teratogenic risk.

• A) Rabies
• B) Tetanus
• C) Pertussis ✅
• D) Hepatitis B

Answer: C - Pertussis PEP with active immunization: Rabies, Tetanus, Hepatitis B, Measles (within 3 days), Varicella. Pertussis does NOT have an effective post-exposure active vaccination protocol.

Microbiology / Virology

• A) Flaviviridae
• B) Rhabdoviridae ✅
• C) Paramyxoviridae
• D) Togaviridae

Answer: B - Rhabdoviridae Rabies is a Lyssavirus of family Rhabdoviridae. Bullet-shaped, negative-sense single-stranded RNA virus.

• A) It is an inactivated vaccine
• B) Dosage is the same for children and adults
• C) Human diploid cell vaccine causes ulceration if given intradermally ✅
• D) Safe to give with live vaccines

Answer: C - FALSE HDCV does NOT cause ulceration intradermally. The vaccine is inactivated (not live), dose is same in children and adults, and it is compatible with live vaccines.

• A) Wound washing only, observe the dog
• B) Wound washing + anti-rabies vaccine only
• C) Wound washing + anti-rabies vaccine + RIG ✅
• D) No treatment if dog appears healthy

Answer: C Transdermal bite = Category III exposure. Requires: local wound care + full vaccine course + RIG on Day 0.

• A) Full 5-dose Essen + RIG
• B) No treatment needed since vaccinated
• C) 2 IM doses on Days 0 and 3, no RIG ✅
• D) Single booster dose only

Answer: C Previously vaccinated = 2 booster doses (Day 0 and Day 3) only. RIG is NOT needed.

• A) 1-7 days
• B) 2-8 weeks (usually) ✅
• C) 3-6 months always
• D) Always less than 1 month

Answer: B - typically 2-8 weeks Range: 4 days to several years (exceptionally). Usually 2 weeks to 3 months. Shorter incubation with head/neck bites or large inoculum. Children tend to have shorter incubation.

• A) Liver cells
• B) Purkinje cells of cerebellum and hippocampal neurons ✅
• C) Respiratory epithelium
• D) Salivary gland cells

Answer: B Negri bodies are most characteristically found in Purkinje cells of the cerebellum and pyramidal cells of Ammon's horn (hippocampus).

Rapid-Fire Summary: Most Repeated NEET PG Rabies Facts