Cold chain refers to the process of maintaining optimal temperature conditions for vaccines from manufacturer to administration. It involves receipt, storage, and delivery of vaccines using various equipment like cold boxes, vaccine carriers, refrigerators, and freezers. Temperature must be monitored daily and vaccines discarded if exposed to unsuitable temperatures as this impacts potency. Proper estimation, documentation, and emergency procedures are important for ensuring vaccine quality during transportation and storage in the cold chain.
2. Objectives :
• Define cold chain.
• Cold chain system.
• Cold chain equipment and its use.
• Maintenance of cold chain equipment.
• Control and monitoring of temperatures.
• Cold chain during immunization sessions.
• Breakdowns and emergencies.
3. What is the cold chain?
• Is the process used to maintain optimal conditions during the
transport, storage and handling of vaccines, starting at the
manufacturer and ending with the administration of the vaccine to
the client.
4. Cold Chain System Activities
in Vaccine Facilities
1. Receipt
2. Storage
3. Delivery
Storage
Receipt Delivery
5. Vaccine stability
• All vaccines are sensitive biological substances.
• Lose potency if exposed to temperature outside the recommended
range.
• Once potency lost, it is irreversible .
7. WHO Policy on use of opened vials of
vaccines
• Opened vials can be used in subsequent immunization sessions and
should be discarded at the end of each day.
• Measles, yellow fever and BCG vaccines discarded after 6 hrs.
• Opened vials discarded immediately if there is any suspicion of
contamination.
8. The cold chain system- elements
1. Personnel: who use and maintain the equipment and provide the
health service.
2. Equipment: for safe storage and transportation of vaccines.
3. Procedures: to manage the programme and control distribution and
use of vaccines.
9. Vaccine potency
• If vaccine loses some potency, appearance doesn’t change.
• Vaccine Vial Monitor (VVM):
a small indicator attached to each vial and records exposure to heat.
If temperature above +8 C, it changes color, i.e. vaccine damaged.
10. Vaccine stock
•Correct quantity should be kept at each stage of the cold chain.
•Not too little, not too much.
•So how much vaccine is needed?!!
11. Estimation of the quantity of vaccine needed:
•Number of children to be immunized during the next 12 months.
•Number of doses needed per child for each vaccine.
•Estimated index of vaccine use (wastage factor i.e. No. of
immunizations given & amount of vaccine used- from previous
records).
12. Estimation of the quantity of vaccine needed:
•Number of vaccine deliveries planned during the next 12 months
(fewer deliveries,, larger and costive cold chain).
•Amount of reserve vaccine stock to be kept in the main store (for
outbreaks, delay in arrival of vaccine delivery).
•Balance of vaccine stock remaining in the main store (stock remaining
should be added to the amount needed, balanced to avoid
overcrowding & expiry of vaccines).
13. Vaccine stock records
• All vaccine storage units must keep Complete & updated stock record.
• Information to be recorded:
1. Name of vaccine, batch number, expiry date & vial size.
2. Quantity received and source of supply.
3. Quantity issued & to whom sent.
4. For BCG, measles & mumps: quantities of diluent received & issued.
5. Balance in stock after each transaction.
6. Date of transaction.
7. Physical stock check at the end of each page.
14. Cold chain equipment & its use
•Equipment for vaccine transportation.
•Equipment for vaccine storage.
15. Equipment for vaccine transportation – cold box
•Isolated container with a tight fitting lid.
•Temperature inside is maintained by icepacks.
•Uses :
•Collection & transport large quantities of vaccine.
•Storage during maintenance periods (cleaning).
•Emergency storage (breakdown of cold chain, power failures).
16. •Cold box is loaded by icepacks.
•Diphteria, pertussis , tetanus vaccines, isolated from ice to not freeze,
put in the centre.
•Vaccines, thermometers, cold chain monitors put.
•OPV, measles,BCG at the bottom and closest to icepacks.
18. Vaccine carriers
•Insulated box with a tight fitting insulated lid.
•uses:
•transportation of small quantities during working day.
•storage of small quantities during working day to avoid frequent
opening of refrigerators .
•storage of small quantities for emergencies .
•same loading instructions.
20. Ice packs
rectangular plastic containers.
to be filled with plain water.
Maintain temperature between 0 to 8 degrees cent. in cold boxes
and vaccine carries .
22. Equipment for vaccine storage- cold room
Is a store where a refrigerating unit generates and maintain
temperature conditions between 0 - 8 degrees cent.
Uses:
Storage of very large quantities of vaccine.
Secure facility for reserve stocks.
Provide distribution point.
24. Equipment for vaccine storage - freezer room
Generates temperature between -15 to - 25 degrees cent.
Designed to keep very large quantities of polio, measles and
pumps vaccines in a frozen state .
29. Control & monitoring of temperature
• Should be a routine activity.
• At the start and end of each working day.
• Monitoring devices include:
1. Thermometers.
2. Temperature record sheets.
3. Refrigerator or freezer thermostat.
4. Cold chain monitor card (CCM).
5. Vaccine vial monitor (VVM).
6. Freeze watch indicator.
7. Vaccine shake test.
30. Thermometers
• Every piece of cold chain should be fitted with a thermometer.
• Different types may be used, commonly mercury thermometer.
32. Temperature record sheets
• Record temperature of refrigerator or freezer.
• Twice daily: in the morning and afternoon.
• Any malfunctions then should be reported.
33.
34. Refrigerator or freezer thermostat
• Used to control storage temperature.
• Thermostat is set to a suitable temperature.
35. Cold chain monitor card
• Designed to follow the vaccines from the point of manufacture to the end.
• Kept together with the vaccine batch.
• Four windows containing indicators, their color change consequently when
temperature rises.
40. Freeze watch indicator
•Shows if the vaccine exposed to temperature below 0 C.
•For Diphteria, pertussis , tetanus vaccines, and hepatitis B vaccines.
•Indicator burst and release red liquid when exposed bellow 0 C.
42. Vaccine shake test
• To determine whether vaccines (Diphteria, pertussis , tetanus vaccines,and
hepatitis B vaccines) has been frozen, sedimentation occurs faster.
• After freezing, vaccine is no longer a uniform cloudy liquid, forms flakes.
• “frozen control sample” is used for comparison.
• Both “tested” and “control” vaccine vials should be produced by the same
manufacturer.
43.
44. Cold chain during immunization sessions
• Vaccines are most vulnerable at this level.
• Precautions should be taken:
1. At the beginning of the working day.
2. During immunization session.
3. At the end of the working day.
4. During outreach immunization session.
45. At the beginning of the working day:
• Check refrigerator temperature.
• Estimate number of vials needed.
• Prepare vaccine carrier loaded with icepacks, do not work directly
from the refrigerator.
• Replace used icepacks by new filled ones for the next day.
46. During immunization session:
• Open vials only after calling the first child.
• Put remaining vaccine back into carrier as quickly as possible.
• Vaccines should be kept out of direct sunlight.
47. At the end of the working day:
• Opened vials returned to refrigerator for the next session Except for
measles and BCG.
• Unopened vials returned to be used first during the next session.
• Record quantity used during the day.
• Record refrigerator temperature on the record sheet.
48. During outreach immunization sessions:
• Same instructions, plus,,,
• Sufficient stock, sufficient icepacks.
• Extra cold box (if no electric supply for a refrigerator).
49. Breakdowns and emergency:
• Any interruption of the cold chain is an emergency.
• Technical faults in refrigerator:
• If refrigerator stops, transfer vaccines to a cold box.
• Check plugs, thermostat, appliances,..
• Call for help.
• Plan for cold chain emergencies:
• Always prepare your plan.
• Define at least two people who know what to do and when.
