Prevention of AEFI (Adverse Events Following Immunization)

Definition

CIOMS/WHO 2012 Classification (Cause-Specific)

Prevention of AEFI - Key Strategies

1. Pre-Vaccination Screening (Contraindication Check)

• Screen all recipients for contraindications and precautions before each vaccination.
• Do not vaccinate if true contraindications exist (e.g., anaphylaxis to previous dose, severe immunodeficiency for live vaccines).
• Note that most conditions labeled as contraindications in the past (mild fever, mild illness, breastfeeding, etc.) are false contraindications - they should NOT prevent vaccination.
• True contraindications include: history of severe allergic reaction to a vaccine component, encephalopathy within 7 days of a previous pertussis vaccine dose.

2. Proper Vaccine Handling and Cold Chain Maintenance

• Maintain the cold chain strictly: most vaccines stored at +2°C to +8°C; OPV and varicella at -20°C.
• Vaccines should never be frozen if they are freeze-sensitive (e.g., DPT, hepatitis B, Td, liquid Hib).
• Discard vaccines that have been frozen inadvertently (use Shake Test or Freeze indicator).
• Use Vaccine Vial Monitor (VVM) to check heat exposure; do not use vaccines with VVM at or past discard point.
• Use cold boxes and ice packs properly - vaccines must not come in direct contact with ice packs (to avoid freezing).
• Follow First Expiry First Out (FEFO) principle for stock rotation.

3. Correct Injection Technique and Administration

• Use correct site, route, dose as specified for each vaccine:
  • BCG - intradermal, right deltoid
  • DPT/DT/TT/Hepatitis B/IPV - intramuscular (anterolateral thigh in infants)
  • Measles/MMR - subcutaneous
  • OPV - oral
• Use sterile, single-use auto-disable (AD) syringes for every injection.
• Never reuse needles or syringes.
• Reconstitute vaccines with the correct diluent provided by the manufacturer only.
• Discard reconstituted vaccines after 4 hours (opened multi-dose vials in field conditions) or as per multi-dose vial policy.
• Do not inject into the gluteal region (risk of sciatic nerve injury and reduced immunogenicity for some vaccines).

4. Avoiding Immunization Error (Programme Errors)

• Using wrong vaccine or wrong diluent
• Non-sterile injection technique (contamination of vaccine or multi-dose vials)
• Injecting into wrong site or by wrong route
• Incorrect dosage
• Vaccine not properly reconstituted
• Vaccine stored improperly before use

5. Post-Vaccination Observation and Management

• All vaccinees should be observed for at least 15-30 minutes after vaccination to detect and manage:
  • Anaphylaxis or severe allergic reactions
  • Vasovagal syncope (fainting)
• Health facilities must have an anaphylaxis emergency kit (adrenaline 1:1000, steroids, antihistamines).
• Ensure the vaccinee is seated or lying down during/after vaccination to prevent injury from fainting.

6. Health Worker Training and Supervision

• Regular training of immunization staff on:
  • Correct vaccination techniques
  • Cold chain management
  • Recognition and management of AEFI
  • Reporting and recording of AEFI
• Supervision and quality audits of vaccination sessions.

7. AEFI Surveillance and Reporting System

• A robust AEFI surveillance system helps detect signals early and take corrective action.
• All serious AEFI must be reported promptly to district/state/national health authorities.
• Events that MUST be reported include: anaphylaxis, severe local reactions, seizures, encephalopathy, paralysis, death.
• Investigating AEFI clusters: a cluster is two or more cases of the same adverse event related in time, place, or vaccine administration.

8. Communication and Counselling

• Inform recipients/parents about:
  • Expected common minor reactions (local pain, swelling, fever) and their management
  • Warning signs requiring medical attention
  • Importance of completing the immunization schedule
• Address vaccine hesitancy through proper communication to maintain trust.

9. Safe Injection Safety and Waste Disposal

• Safe disposal of used syringes and needles in puncture-proof containers (hub-cutters, safety boxes).
• Prevents needle-stick injuries and re-use of discarded syringes.

Summary Mnemonic: "CCTISH"

• C - Contraindication screening before vaccination
• C - Cold chain maintenance
• T - Training of health workers and correct technique
• I - Injection safety (AD syringes, sterile technique)
• S - Surveillance and reporting system
• H - Health education and post-vaccination observation

Important Points for Exam

1. Immunization error-related AEFI is the ONLY fully preventable category - previously called "programme error."
2. The Shake Test is used to detect freeze-damaged vaccines.
3. Auto-disable (AD) syringes are mandatory in national immunization programmes.
4. Anaphylaxis is the most serious immediate AEFI - epinephrine is the drug of choice.
5. India's AEFI surveillance is integrated under the UIP (Universal Immunization Programme) - AEFI is reported monthly via IDSP.