Overview
Definition:
Post-exposure prophylaxis (PEP) for rabies in children involves a combination of wound management, rabies vaccine administration, and sometimes rabies immunoglobulin (RIG) to prevent the development of rabies after a potential exposure to a rabid animal
Rabies is a fatal viral zoonotic disease affecting the central nervous system.
Epidemiology:
Rabies remains a significant public health concern, particularly in Asia and Africa, with India accounting for a substantial proportion of human rabies deaths globally
Children are particularly vulnerable due to their increased risk of animal bites and potential lack of understanding of appropriate preventive measures.
Clinical Significance:
Prompt and appropriate rabies PEP is the single most effective measure to prevent rabies post-exposure
Failure to administer correct PEP can lead to invariably fatal encephalitis
Understanding the nuances of PEP in pediatric populations, including dosing and schedule adherence, is critical for pediatric residents and DNB/NEET SS aspirants.
Exposure Assessment
Animal Type:
Dogs (most common in India), cats, bats, monkeys, foxes, jackals
Unprovoked attacks are more suspicious
Domestic animals (dogs, cats) that are healthy and observed for 10 days are unlikely to transmit rabies.
Type Of Exposure:
Any bite or scratch that breaks the skin
Mucous membrane contact with saliva from a rabid animal
Non-bite exposures like contact with infectious material from a rabid animal (e.g., neurological tissue, laboratory accident) require careful risk assessment.
Animal Status:
Is the animal wild or domestic? Has it been vaccinated against rabies? Was the bite provoked or unprovoked? If a domestic animal, can it be observed for 10 days? In India, for stray dog bites, presumptive treatment is often initiated.
Wound Classification:
Category I: No contact, no bites
No PEP needed
Category II: Nips, abrasion, minor bites not breaking the skin
PEP indicated if animal is rabid or rabid/unknown
Category III: Single or multiple punctures or lacerations or avulsions
contamination of mucous membranes
PEP indicated for all cases, irrespective of animal status, particularly if from a high-risk area or animal.
Wound Management
Immediate Care:
Wash the wound thoroughly with soap and water for at least 15 minutes
This is a critical first step and significantly reduces viral load
Apply an antiseptic solution like povidone-iodine or ethanol (70%).
Surgical Intervention:
Thorough wound irrigation and debridement are essential
Suturing should be avoided if possible, especially in category III exposures, as it can create dead space for the virus
If suturing is necessary, it should be done delayed or loosely
Tetanus prophylaxis should be administered as per routine immunization schedule.
Antimicrobial Therapy:
Antibiotics are generally not indicated for the bite wound itself unless there are signs of secondary bacterial infection
The primary focus is on rabies prevention.
Vaccination Schedule
Types Of Vaccine:
Modern rabies vaccines are cell-culture based, such as Purified Chick Embryo Cell Vaccine (PCECV) or Human Diploid Cell Vaccine (HDCV)
Ensure the vaccine used is WHO-approved or licensed by national regulatory authorities.
Intramuscular Administration:
The most common schedule involves intramuscular injections
The deltoid muscle is the preferred site in adults and older children
In infants and young children, the anterolateral aspect of the thigh can also be used.
0-day Schedule:
On day 0 (the day of exposure), administer the first dose of vaccine
For Category III exposures, RIG should also be infiltrated around the wound site on day 0, if available.
Follow Up Doses:
For individuals not previously vaccinated: 4-dose Essen regimen (days 0, 3, 7, 14) or 2-dose updated Thai Red Cross regimen (days 0, 7, with intradermal doses on day 0 and 7 is also an option, but intramuscular is standard in India for residents)
For immunocompetent individuals previously vaccinated: Only vaccine booster doses (days 0 and 3 IM) are required, no RIG.
Intradermal Administration:
Intradermal (ID) administration can be used as an alternative to intramuscular (IM) injections in certain protocols, often with smaller doses at multiple sites
However, IM administration is the standard of care in India for primary PEP in most settings and for residents to administer
Ensure proper training if ID is considered.
Rabies Immunoglobulin
Indications:
Rabies immunoglobulin (RIG) is indicated for Category III exposures and for Category II exposures in severely immunocompromised individuals, or when immediate post-exposure treatment is delayed beyond 7 days
It provides passive immunity.
Administration:
RIG should be administered as soon as possible after exposure, preferably on day 0
If administered late, it can still be given up to day 7 post-vaccination
It is given as a single dose, infiltrated as deeply as possible around the wound site
If the volume is large, it can be divided between multiple sites.
Types Of RIG:
Human rabies immunoglobulin (HRIG) is preferred over equine rabies immunoglobulin (ERIG) due to a lower risk of hypersensitivity reactions
Ensure availability and proper administration technique.
Contraindications:
RIG is generally not indicated if PEP was started within 7 days of exposure and is given concomitantly with vaccine
RIG should not be given after the first dose of vaccine on day 0, as it can interfere with the immune response to the vaccine.
Special Populations And Considerations
Immunocompromised Children:
Children with conditions like HIV, on immunosuppressive therapy, or post-chemotherapy may require a more robust PEP regimen, possibly including RIG even for Category II exposures, and additional vaccine doses
Consult infectious disease specialists.
Bat Bites:
Bat bites, even minor, are considered high-risk
All bat bites require PEP
Due to the difficulty in assessing rabies status in bats, if a bat is found in a room with a sleeping child and the child is bitten or cannot be assessed for exposure, PEP should be considered.
Delay In Treatment:
If there is a delay in initiating PEP, it is still beneficial to start it as soon as possible
If RIG was not administered on day 0, it should not be given later than day 7 of vaccine administration
Vaccine doses should still be completed.
Post Vaccination Monitoring:
For immunocompetent individuals completing the full PEP schedule, post-vaccination serological testing is generally not required
However, for immunocompromised individuals or those with ongoing exposure risk, monitoring antibody titres may be considered.
Key Points
Exam Focus:
Rabies PEP schedules (WHO-recommended, Indian guidelines), indications for RIG, wound management principles, differences in PEP for previously vaccinated vs
unvaccinated individuals are high-yield for DNB/NEET SS.
Clinical Pearls:
Always wash the wound thoroughly with soap and water first
Prioritize RIG administration on day 0 for Category III exposures
Emphasize to parents the importance of completing the vaccine schedule
In India, strays are a major concern
presumptive treatment is common.
Common Mistakes:
Incorrectly classifying exposure category
Delaying or omitting wound washing
Incorrectly administering RIG (e.g., not infiltrating locally)
Omitting RIG when indicated
Not completing the vaccine schedule
Administering RIG after day 7 of vaccination.