This document discusses India's large universal immunization program (UIP) that protects children against six vaccine-preventable diseases. It explains that vaccines must maintain safety and potency, which can be diminished if exposed to inappropriate temperatures. A cold chain system is essential to ensure the right vaccines reach people at the right place and time at the proper temperature conditions. The cold chain uses equipment like walk-in freezers, walk-in coolers, deep freezers, and ice-lined refrigerators to store and transport vaccines within the required temperature ranges while maintaining hold-over times during power outages. Proper temperature monitoring is crucial for vaccine effectiveness.

1. The Cold Chain System
Dr. Anuj Singh
Asst. Professor
Community Medicine Dept.
UIMS, Prayagraj

3. Immunization is the most effective method of
preventing childhood diseases
 India has largest UIP in the world
Under UIP children are protected against 6
vaccine preventable diseases.
Background

4. Six Vaccine preventable
diseases:
1. Diphtheria
2. Pertussis
3. Tetanus
4. Poliomyelitis
5. Measles
6. Pulmonary tuberculosis

5. Immunization is delivered through:
a) District Hospital
b) Community health centers (CHC)
c) Primary health centers (PHC)
d) Aganwadi centers

6. Vaccines are sensitive biological products. Some
vaccines are sensitive to freezing , some to heat and
others to light.
Vaccine potency:
meaning its ability to adequately protect the
vaccinated patient, which can be diminish when the
vaccine is exposed to inappropriate temperatures.
Once lost, vaccine potency cannot be regained.
A vaccine must have 2 characteristics:
i.e. Safety and Potency

7.  The success of national immunization programme is
highly dependant on supply chain system for delivery
of vaccines and equipment, with a functional system
that meets 6 rights of supply chain
 The right vaccine in the right quantity at the right
place at the right time in the right condition (no
temperature breaks in cold chain) and at the right cost

8. Cold Chain

17. 1.Walk in freezer
 It maintains a temperature
between - 15°C to - 25°C.
 WIF are usually installed at
national, state and regional
vaccine stores.
 It is used for bulk storage of
OPV vaccine and for
preparation of frozen ice
packs for vaccine
transportation.

18. 2.Walk in cooler
 These Walk-in-coolers
are installed at
government medical
store depots, state and
regional vaccine stores.
 Maintain a temperature
of +2°C to +8°C.
 used for storage of large
quantities of all UIP
 vaccines

19. 3. Deep freezer (DF)
• The cabinet temperature
maintained between
-15° to - 25°C.
• Used for storing of OPV for 3
months (district level and above
only) and also for freezing of ice
packs (at sub-district level only).
• Unlike ILR, the DF has or limited
hold-over time which is dependent
on the number of frozen ice packs
in it and the frequency of lid
opening.

22. 4. Ice lined refrigerator (ILR)
 Most important link in the
cold chain is ice lined
refrigerator (ILR).
 ILRs maintain
temperature between
+2°C to + 8°C
 Used to store vaccines at
district and sub-district
level.
 Holdover time: 24-hrs
after 8hrs of continuous
power supply.

26. Hold-over time of the equipment
• In the event of power failure , hold-over time is
defined as the "time taken by the equipment to
raise the inside cabinet temperature from its
temperature at the time of power cut, to maximum
temperature limit of its recommended range.”
• E.g. in case of ILR if the cabinet temperature is +4°C at
the time of power-cut, then the time taken to reach +8°C
from +4°C will be hold-over time for that ILR.

27. (a) Ambient temperature: More the ambient temperature
less will be the hold-over time;
(b) Frequency of opening of lid and use of basket;
(c) Quantity of vaccines kept inside with adequate space
between the containers (Equipment empty/loaded);
(d) Condition of ice-pack lining (Frozen/partially
frozen/melted).
Hold-over time depends on the
following factors :

30. Domestic refrigerator
(front load refrigerator)
• Domestic refrigerators can
also maintain the
temperature between +2°C
to +8°C, but the hold-over
time and capacity to store
vaccines/ freeze icepacks is
limited. They can be used
for storage of vaccine at
private clinics and nursing
homes, provided continuous
power supply is ensured.

40. Temperature charting