Maintaining the cold chain means keeping vaccines at the right temperature throughout distribution, storage and use. The cold chain can be maintained by:
- Never exposing vaccines to heat or freezing conditions, especially during transportation from one point to another.
- Always using a cold box to keep the vaccines cold during transport and immunisation.
- All vaccines should be kept in a refrigerator at a temperature of 2–8°C.
- Defrosted OPV should not be kept in the freezer or be allowed to freeze again.
- Use a metal dial thermometer or a fridge-tag for all vaccines (Min-max thermometer not recommended).
- Do not let Hexavalent (DTaP-IPV-HB-Hib), HPV, PCV, RV, Td and TT vaccines touch the evaporator at the back of the fridge as they may freeze. Do not freeze these vaccines. Do not use frozen vaccines. If unsure, do shake test to check whether vaccines have frozen.
- Monitor and record fridge temperature twice daily.
- Leave space between each tray to allow cold air to circulate.
- Do not keep food in the same fridge as the vaccines.
- If possible do not keep other medications e.g. insulin etc. in the vaccine fridge.
- Do not keep blood and other specimens in the vaccine fridge.
Correct packing of the cold box
- Fully conditioned ice packs (the ice should rattle inside the pack) are placed on the bottom, at the sides and on top.
- If there are not enough ice packs, place available ice packs at the sides and on top of the vaccines.
- Td, TT, HPV, PCV, RV and Hexavalent vaccines must not be allowed to freeze.
- Keep measles and polio vaccines very cold - place on bottom of the cold box, closest to the ice packs.
- BCG can be placed anywhere in the box.
- Keep the lid firmly closed and the box out of the sun.
- Keep a thermometer and a freeze tag in the cold box with the vaccines and the temperature at 2–8°C.
- Live vaccines (BCG, OPV, measles) are very sensitive to heat, sunlight and skin antiseptics.
How to pack your fridge correctly
- Vaccines should be stored in a specific vaccine fridge. However, if unavailable store the vaccines in a domestic fridge, as follows:
- Top shelf: measles and polio vaccines in the coldest part.
- Middle shelf: BCG, Td, Hexavalent (DTaP-IPV-HB-Hib), HPV, RV, PCV and TT vaccines (do not freeze) with sufficient diluent for the BCG and measles for 2 days.
- Do not let Td, Hexavalent (DTaP-IPV-HB-Hib), HPV, RV, PCV and TT vaccines touch the evaporator plate at the back of the fridge as they are destroyed by freezing.
- Do not keep vaccines in the fridge door.
- Store the same kind of vaccines together in one tray.
- Leave about 2cm space between each tray to allow the cold air to move around.
- Bottles filled with salt water stored in the bottom of the fridge will keep the fridge contents cold when the door is opened.
- Do not keep food in the same fridge as the vaccines to avoid unnecessary opening of the door.
- There should be a contingency plan written and posted on every vaccine fridge of what to do in the event of a power failure.
- Monitor and record temperature twice daily.
CAUTION
Do not use vaccines that have expired, missed the cold chain or that VVM has reached discard point.
Keep the fridge temperature between 2–8°C.
Note: All vaccines with a “T” in the name are sensitive to freezing –TT, Td, HexavalenT, RoTavirus, HepaTiTis B and even diluents. All diluents (measles and BCG) should never be frozen.