Background Immunization- well-known and effective methods of preventing childhood diseases India has one of the largest UIP in the world Under UIP, all the children in the entire country are protected against the 6 deadly Vaccine Preventable Diseases (VPD) Services provided district hospitals, community health centers (CHC), primary health centres (PHC) and sub-centers. Important elements for improving the immunization is cold chain and vaccine logistics management which is backbone of immunization programme.
It is a universal fact that all vaccines are sensitive to heat & light and some are sensitive to freezing A vaccine must have two characteristics, one is safety and other is potency vaccines loose their potency if they are not stored or transported at an appropriate temperature and condition . A quantitative measure of the specific ability of the vaccine product to achieve an intended biological effect defined in a suitable biological assay based on the attribute of the product that is linked to the relevant biological properties.
What is Cold chain?
Vaccines loose their potency due to either exposure to Excessive heat or Excessive cold (some vaccines like DPT, TT, Hep. B) . Light (some vaccines like BCG and measles) .
Vaccines: (BCG- Bacille Calmette Guerin): Tuberculosis - Oral polio vaccine (OPV) - Measles, mumps and rubella (MMR) - MenC Vaccine ( Meningococcal C Vaccine ) - DT (diphtheria and tetanus) Acellular pertussis ( aP ) , Inactivated polio virus (IPV), Haemophilus influenzae type B vaccine , often called Hib vaccine. – Tetanus toxoid (TT) -
Monitoring of Cold Chain The physical appearance of the vaccine may remain unchanged even after it is damaged The loss of potency due to either exposure to heat or cold is permanent and can not be regained. Heat Damage- All vaccines are damaged by temperatures more than +8°C. Checking for heat damage: The Vaccine Vial Monitor contains a heat-sensitive material, placed on a vaccine vial to register cumulative heat exposure over time.
Cold chain equipments
1. Walk-in-Freezers (WIF) Installed in all of the states and larger divisional head quarters. They maintain a temperature around -20°C. bulk storage of OPV, and also to prepare frozen ice packs at state stores. Available in sizes of 16.5 Cum. and 32 Cum.
2. W alk -in- Coolers (WIC) Established at regional levels , which store vaccines for about 4-5 districts for 3 months. Maintains temperature of +2°C to +8°C . Used for storage of large quantities of vaccines, like DPT, DT, TT, Measles, BCG, Hepatitis B. WIC/WIF store vaccines of three months requirement and 25% buffer stock for the districts they cater. Available in sizes of 16.5 Cum. and 32 Cum.
3. Deep Freezer Available in different sizes: 264 liters or 380 icepacks 72 liters or 130 icepacks 80 liters or 140 ice packs. C a bine t t emp e r a tu r e is mai n t ain e d bet w e e n - 15° C t o - 25°C. Used for storing of OPV (district level and above only) and also for freezing ice packs. All districts have been provided 2-5 large deep freezers Most PHCs have been provided with one small deep freezer.
4. Ice Lined Refrigerator Available in different sizes: 108 liters or 26000 to 30000 doses 45 liters or 11000 to 13000 doses 100 liters or 24000 to 28000 doses 50 liters or 12000 to 14000 doses Larger ILR is supplied to district headquarters and PHC . Top opening because they can hold the cold air inside better than a refrigerator with a front opening. There is a lining of water containers (Ice packs or tubes) fitted all around the walls and held in place by frame. Keep vaccine safe with as little as 8 hours continuous electricity supply in a 24-hour period.
Storage of vaccine in ILR The ILR has got two sections – the top and bottom. Bottom of the refrigerator is the coldest place and is shown as section A.
Hold over time of equipments Time taken by the equipment to raise inside vaccine temperature at the time of power failure from its minimum temperature to 10°C. Hold over time depends on the following factors: Ambient temperature. Number of frozen Ice Packs inside the D eep freezer . Frequency of opening of lid and use of basket. Quantity of vaccines kept inside with adequate space between the containers. Condition of icepacks inside Non electrical cold chain equipment
1. Cold Box Big insulated boxes Mainly used to collect and transport large quantities of vaccines In emergency they can be used to store vaccines as well as frozen ice packs. Store vaccines for transfer up to five days, if necessary for outreach sessions or when there is power cut. Available in different sizes: 5& 8 liters for 1500 & 2400 doses 20-22 liters for 6000 -6600 doses
2. Vaccine Carriers Vaccine carriers are made of insulated material for transportation . Ice packs are used for keeping vaccines cold during transportation up to 12hrs. Used for carrying small quantities of vaccines (16- 20 vials) to the sub-centers or session sites. In comparison with cold boxes, vaccine carriers have a smaller volume, suitable for use by health workers during immunization campaigns and out-reach services.
3. Day Carriers
Preparation of vaccine carriers Take out the required number of ice packs from the deep freezer and wipe them dry. Keep them out side for conditioning. Place four conditioned ice packs in the carrier wait till temperature to fall to <8 ° C in the carrier Wrap vaccine vials and ampoules in thick paper before putting in polythene bag so as to prevent them from touching the ice packs.
Cont…. Place some packing material between `T’ series vaccine and the ice packs. Place foam pad at the top of ice packs Ensure that some ice is present in the ice packs while conducting immunization sessions. Secure the lid tightly.
Packing a vaccine carrier
ICE GEL PACK Coolant. A coolant is a substance, typically liquid or gas, that is used to reduce or regulate the temperature of a system. Antifreeze, a solution of a suitable organic chemical (most often ethylene glycol , diethylene glycol , or propylene glycol ) in water, is used when the water-based coolant has to withstand temperatures below 0 °C