Vaccine Storage and Handling

Cold Chain System - Chill Factor Fundamentals

System ensuring vaccines are stored & transported at recommended temperatures from manufacturer to administration, maintaining potency.

• Core Principle: Preserve vaccine efficacy, prevent Vaccine Preventable Diseases (VPDs).
• Essential Components:
  • Personnel: Trained staff.
  • Equipment: Cold rooms, Deep Freezers (DFs), Ice-Lined Refrigerators (ILRs), cold boxes, vaccine carriers.
  • Procedures: Standard Operating Protocols (SOPs).
• Chill Factor:
  • Risk of freeze damage to freeze-sensitive vaccines (e.g., T-series: TT, DPT, Pentavalent, Hep B, IPV, PCV, liquid Rotavirus).
  • Store these between +2°C and +8°C.
  • Freezing irreversibly destroys their potency (loss of adjuvant effect for adsorbed vaccines).

⭐ Most heat-sensitive: Oral Polio Vaccine (OPV). Most freeze-sensitive (common EPI vaccines, excluding diluents): Hepatitis B.

Temperature Monitoring - Thermometer Tactics & VVMs

• Thermometers: Essential for daily temperature checks.
  • Types: Dial, alcohol, stem (for ILR), digital; data loggers (continuous monitoring).
  • Placement: Central fridge area; NOT doors or near cooling coils.
  • Schedule: Read & record twice daily (AM/PM) in temperature log.
  • Action: Immediate correction if outside +2°C to +8°C. ![Image of vaccine storage thermometers and VVM stages]
• Vaccine Vial Monitors (VVMs): Track cumulative heat exposure.
  • Indicator: Inner heat-sensitive square darkens progressively.
  • Reading (Inner Square vs. Outer Circle):
    • Square Lighter: Usable.
    • Square Matches (Discard Point A): Use first (if passes Shake Test for freeze-sensitive).
    • Square Darker (Discard Point B): DISCARD.
  • Types: VVM2, VVM7, VVM14, VVM30 (days to reach discard point at +37°C).
  • Limitations: VVMs do NOT detect freezing, vaccine potency, or expiry date.

  ⭐ Critical VVM Discard Rule: If inner square is same color as, or darker than, outer circle - DO NOT USE the vaccine.

Vaccine Storage & Handling - Equipment & Key Protocols

• Equipment:

  • ILR: +2°C to +8°C. Store freeze-sensitive (DPT, TT, HepB, IPV, Penta) in baskets, avoid ice-lining. OPV, Measles (if not DF) also here.
  • Deep Freezer (DF): -15°C to -25°C. Stores OPV, Measles, MR, JE (lyophilized).
  • Cold Box: Transport, 48-96 hrs.
  • Vaccine Carrier: Outreach, 4 conditioned ice packs, 12-18 hrs.

• Key Protocols:

  • Temperature Monitoring: Twice daily; dial/alcohol thermometer.
  • Shake Test: For freeze-sensitive liquid (DPT, TT, HepB, Penta, IPV) if freezing suspected.
    • Control (unfrozen) vs. Test (suspected).
    • Result: Test sediments slower/cloudy = Discard.
  • Open Vial Policy: Multi-dose liquid (OPV, DPT, TT, HepB, Penta). Use up to 28 days (VVM ok, cold chain, not expired, aseptic).
    • ⚠️ Reconstituted (BCG, Measles): discard 4-6 hrs / end session.
  • VVM: Indicates cumulative heat exposure.
  • Hub cutter & Needle pit: Safe sharps disposal.

⭐ The "Shake Test" is crucial for adsorbed vaccines like DPT, Pentavalent, HepB, TT, and IPV, as freezing potentiates their reactogenicity and reduces immunogenicity.

High‑Yield Points - ⚡ Biggest Takeaways

• Most vaccines: +2°C to +8°C. OPV, Measles, MR, JE (lyo) in freezer (-15°C to -25°C).
• Never freeze sensitive vaccines (DPT, TT, HepB, IPV, Pentavalent).
• Shake Test detects prior freezing of adsorbed vaccines (DPT, HepB).
• VVM: Discard if inner square darker/same as outer circle (heat exposure).
• Cold Chain maintains potency from manufacturer to beneficiary.
• ILRs standard at PHCs; Open Vial Policy for specific multi-dose vials.