What is the post‑exposure rabies vaccination protocol in the Philippines?

Post-Exposure Rabies Vaccination Protocol in the Philippines

For previously unvaccinated individuals in the Philippines, administer a 4-dose intramuscular rabies vaccine series on days 0,3,7, and 14, combined with rabies immunoglobulin (20 IU/kg) on day 0, following immediate thorough wound cleansing. This protocol follows international ACIP guidelines and has been extensively validated in Philippine clinical settings 1.

Protocol for Previously Unvaccinated Persons

Immediate Wound Care (Day 0)

• Thoroughly cleanse all wounds with soap and water immediately
• If available, irrigate wounds with a virucidal agent (povidone-iodine solution)
• This step is critical and should never be delayed 1

Rabies Immunoglobulin (RIG) Administration (Day 0)

• Dose: 20 IU/kg body weight of equine or human RIG
• Technique: Infiltrate the full dose around and into the wound(s) if anatomically feasible
• Any remaining volume should be administered intramuscularly at a site distant from vaccine administration
• Critical timing: Must be given on day 0; if missed, can be administered up to and including day 7 1
• Never administer RIG in the same syringe or same anatomic site as the vaccine 1

Important caveat: Purified equine RIG (pERIG) has been extensively used in the Philippines with excellent safety and efficacy profiles 2. Studies from the Research Institute for Tropical Medicine showed 143 of 151 laboratory-confirmed rabies exposures survived using this protocol 2.

Vaccine Schedule

Standard 4-dose regimen for immunocompetent persons:

• Day 0: 1.0 mL intramuscularly (as soon as possible after exposure)
• Day 3: 1.0 mL intramuscularly
• Day 7: 1.0 mL intramuscularly
• Day 14: 1.0 mL intramuscularly

Injection site:

• Adults and older children: deltoid area only
• Younger children: anterolateral aspect of the thigh is acceptable
• Never use the gluteal area - this results in diminished immunologic response 1

Vaccines used in the Philippines: Purified Vero Cell Rabies Vaccine (PVRV) or Purified Chick Embryo Cell Vaccine (PCECV) - both have equivalent immunogenicity 3, 4

Special Population: Immunocompromised Patients

• Use a 5-dose regimen on days 0,3,7,14, and 28
• Still administer RIG on day 0 1

Protocol for Previously Vaccinated Persons

For individuals with documented prior rabies vaccination (pre-exposure or post-exposure with cell-culture vaccines):

• Wound cleansing (same as above)
• NO rabies immunoglobulin - RIG should not be administered as it may inhibit the anamnestic response 1
• 2-dose vaccine series only:
  • Day 0: 1.0 mL intramuscularly
  • Day 3: 1.0 mL intramuscularly

Alternative Intradermal Regimen (Resource-Limited Settings)

The Philippines has extensive experience with intradermal (ID) administration, which is cost-effective and widely used in Animal Bite Treatment Centers (ABTCs):

Updated Thai Red Cross (TRC) Regimen

• Days 0,3,7: 0.1 mL at 2 sites intradermally (2-2-2 pattern)
• Day 28: 0.1 mL at 2 sites intradermally
• Plus RIG on day 0 for Category III exposures 4

Accelerated 1-Week, 4-Site Regimen

• Days 0,3,7: 0.1 mL at 4 sites intradermally (4-4-4 pattern)
• Non-inferior to the TRC regimen with 100% seroconversion by day 14 5
• Can be used with or without RIG depending on exposure category
• Reduces visits from 5 to 3, improving compliance

Clinical evidence: A Philippine trial of 600 patients showed the 1-week regimen achieved 100% seroconversion for Category II exposures without RIG, and 99.4% with RIG for Category III exposures 5.

Common Pitfalls and How to Avoid Them

Vaccine Shortages

• The Philippines experiences periodic vaccine shortages at ABTCs, with out-of-pocket expenses ranging from $5.53 to $37.83 per patient when government supplies run out 6, 7
• Solution: Contact multiple ABTCs or the Research Institute for Tropical Medicine (RITM) in Muntinlupa if local supplies are unavailable

Incomplete Treatment

• Only 78% of patients complete the recommended course in community ABTCs 6
• Main reasons: lack of time (most common), insufficient funds
• Solution: Emphasize to patients that rabies is 100% fatal once symptoms appear; all doses are essential

RIG Unavailability

• RIG shortages are more problematic than vaccine shortages
• In 2023, only 42.65% of Category III patients received ERIG at one ABTC 7
• Solution: Category III exposures (deep wounds, multiple wounds, wounds on head/neck/hands) absolutely require RIG - consider referral or repatriation if unavailable

Age-Related Considerations

• Two documented PEP failures in the Philippines involved children under 12 weeks of age with severe head/neck wounds 2
• Critical point: Very young children with severe Category III exposures require meticulous wound care and may need enhanced monitoring

Delayed Treatment

• The 5-dose regimen (days 0,3,7,14,28) was previously used but has been replaced by the 4-dose regimen based on evidence showing the fifth dose does not improve outcomes 8, 1
• Treatment should begin immediately - do not wait for animal observation results
• 85% of dog bites in the Philippines are from animals that are not truly rabid, but prophylaxis must not be delayed pending observation 6

Monitoring and Follow-Up

• No routine serologic testing is required after completing the 4-dose regimen in healthy individuals 1
• Animal observation for 10 days can help determine if the full series is needed, but never delay starting PEP
• Healthcare workers with repeated exposures maintain protective antibodies for 3-5 years after multiple vaccine regimens 9