Chapter 23.4 Vaccine Storage and Cold Chain Karan Singh Sagar, Manish Jain. The Childhood Years PART V MORE ON THIS TOPIC

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1 906 IN A NUTSHELL The Childhood Years PART V 1. Proper scheduling of available vaccine is the key to proper utilization of available vaccines and achieving good protection against prevailing VPDs. 2. The few key determinants of an optimal immunization schedule include immunological principles, epidemiological aspects and programmatic issues. 3. There are key differences in the vaccination schedules designed for individual and community protection. 4. While safety and efficacy are the key issues for individual schedule, cost and programmatic issues override all the considerations in schedules planned for community protection. 5. There is marked heterogeneity in the vaccination schedules of different countries. 6. WHO-SAGE gives recommendations to NITAGs of individual country to formulate their national vaccine policies including their schedules. 7. NTAGI in India gives recommendations to Government of India regarding planning of its immunization schedule. ACVIP of IAP devises its immunization schedule for pediatricians working in private sector. 8. Catch-up immunization, adolescent immunization, improvement in coverage, adoption of new vaccine technology, incorporation of new lifesaving vaccines, support to innovation and research and development related to vaccines are few key initiatives urgently needed to improve our existing national immunization schedule. MORE ON THIS TOPIC Choudhury P. Scheduling of Vaccine. IAP Text Book of Vaccines, In: Vashishtha VM, Agarwal R, Sukumaran T (Eds). New Delhi: Indian Academy of Pediatrics, Jaypee Brothers Medical Publilshers; Indian Academy of Pediatrics Committee on (IAPCOI). Consensus recommendation on and IAP Timetable Indian Pediatr. 2012;49:560. Scheduling of Vaccines. In: Vashishtha VM, Choudhury P, Bansal CP, Yewale VN, Agarwal R (Eds). IAP Guidebook on Gwalior: National Publication House, Indian Academy of Pediatrics; Chapter 23.4 Vaccine Storage and Cold Chain Karan Singh Sagar, Manish Jain Safety and potency are the two key characteristics underlying success of any vaccine resulting in reduction in incidence of vaccine preventable diseases (VPDs) and associated mortality and morbidity. These key characteristics are in most part dependent on and determined by proper management of vaccines and vaccine products, which includes storage in the recommended conditions and handling during transportation, distribution and use. The exposure of vaccines (and vaccine products) to temperature (and light) outside the recommended ranges may lead to reduction in potency and the protection it results after administration to the beneficiaries. This not only leads to improved immunization safety and efficacy but also serves to reduce program costs by preventing high wastage rate. Cold chain It is the system used for storage and transportation of vaccines (and vaccine products) in the recommended conditions and acceptable temperature ranges from point of manufacture Figure 1 Cold chain Source: in Practice, Module 3, WHO until it is administered to the beneficiary (Fig. 1). Effective cold chain network is the backbone for ensuring quality immunization services in any country. The key elements of cold chain system include: personnel (for vaccine management, storage and distribution), equipment (for vaccine storage and transportation, both electrical and nonelectrical) and procedures including monitoring (for ensuring vaccine storage and transportation under recommended conditions). TERMINOLOGY USED IN COLD CHAIN SYSTEM Hold over time of cold chain equipment It is the time in hours for which all points inside the vaccine compartment of a vaccine refrigerator remain below +10 C, at the maximum ambient temperature of the temperature zone for which appliance is rated, after the power supply has been disconnected. For example, the minimum storage temperature of an ice-lined refrigerator (ILR) is +2 C, so the time taken for cabinet temperature to reach +10 C would be the hold over time of that ILR. In case of vaccine freezers, the hold over time is the time in hours for which the temperature inside the compartment remains below 5 C.The hold over time applies to both electrical and nonelectrical cold chain equipment, and for a specific equipment, it depends on the ambient temperature (with inverse relationship), frequency of opening the equipment, quantity of vaccines stored, spacing between vaccine boxes and condition of water-packs (in nonelectrical equipment). Vaccine storage capacity It is the actual volume available inside the equipment (refrigerator, freezer, cold box or vaccine carrier) for the storage of vaccines. This is specified by the equipment manufacturer in the product specifications and can also be measured by physical methods. Water-pack freezing capacity This applies to water-pack freezers and is the maximum weight (kg/24 hour) of water-packs that can be fully frozen, in one batch, within a period of 24 hours. Refrigerants and foaming agents [Chlorofluorocarbons (CFC)] R11 and R12 have been popular refrigerant gases used in compression

2 refrigeration circuits and as foaming agents for the insulation of refrigerators, cold boxes and vaccine carriers. But as these are potent greenhouse gases having depleting effect on stratospheric ozone layer, therefore as per Montreal Protocol CFC equipment are condemned for use in industrialized nations (since January 1st, 1996) as well as in the developing nations (since January 1st, 2010). Refrigerants now recommended and which are now being used by manufacturers include hydrofluorocarbon (HFC) 134a and hydrocarbon R600 (isobutene); and the foaming agents that are being used are cyclopentane and R141b. Other gases being investigated for these purposes are HPC-245fa, HFC-365mfc, HFC- 234a, isopentane and n-pentane. Vaccine wastage factor This indicates how much additional vaccine should be ordered in order to allow for the given wastage rate. The vaccine wastage rate can vary according to session size, session plan, vial presentation, supply management and many other characteristics. Each country should monitor its own vaccine wastage; however, there are indicative wastage levels for different vial sizes for lyophilized (single dose: 5%; 2 6 dose vial: 10%; dose vial: 50%) and liquid vaccines (single dose: 5%; 2 6 dose vial: 10%; dose vial: 25%). Vaccine wastage can be due to unavoidable and avoidable reasons. Wastage occurring due to discarding reconstituted vaccines at the end of session or after recommended usage time, poor stock management leading to oversupply, wastage due to expiry before use, failure of cold chain leading vaccines to exposure to higher or lower temperature, administering incorrect dosage to the beneficiaries, failure in using multidose vials in correct manner and breakage, etc. are the important avoidable reasons which can be addressed through proper planning and compliance to guidelines. Volume per dose This refers to the volume occupied by each dose of vaccine, including the volume occupied by its packaging (and volume of diluent, if applicable) in the cold chain equipment at time of storage. The volume per dose depends on the type of vaccine and is an important factor to be considered for estimation of vaccine storage requirements. VACCINE STORAGE IN COLD CHAIN Each vaccine is different in terms of its constituents and therefore each one of them have a recommended range of temperature for storage and transportation, clearly specified in the product specifications issued by the manufacturer. Temperature ranging from +2 C to +8 C is generally safe for storage of majority of vaccines, except a few which need to be stored at negative temperature between 15 C and 25 C [e.g., oral polio vaccine (OPV)]. Vaccines exposed to temperature above +8 C gradually loss their potency over time. This can be either in form of an exposure to lot of heat over a short period of time (e.g., keeping vaccine in direct sunlight on a summer day) or exposure to small amount of heat over a longer period of time (e.g., frequent opening the lid of storage equipment). Heat-sensitive vaccines are shown in Figure 2. There are some vaccines, e.g., T series vaccines [e.g. diphtheria tetanus pertussis (DTP), diphtheria tetanus (DT), tetanus toxoid (TT), dt, Td and Hepatitis B), liquid Haemophilus influenzae type b (Hib) and liquid pentavalent vaccine, which are damaged by freezing and/or exposure to freezing temperature. Hepatitis B vaccine is most sensitive to the freezing temperature. Freeze sensitivity of vaccines is shown in Figure 3. There are some vaccines which are sensitive to strong light. These vaccines loss their potency overtime followed by exposure to ultraviolet component of sunlight and fluorescent (neon) light. Such vaccines are packaged and supplied in vials having darkbrown glass which gives some protection from damage due to light exposure, but still care must be taken to keep them covered and protected from strong light during storage, transportation and use. Figure 2 Heat sensitivity of different vaccines Abbreviations: BCG, bacillus Calmette Guérin; DT, diphtheria tetanus; DTP, diphtheria-tetanus pertussis; MR, measles and rubella; MMR, measles, mumps, rubella; HepB, hepatitis B; Hib, Haemophilus influenzae type b; IPV, inactivated poliovirus; OPV, oral polio vaccine; Td, tetanus diphtheria; TT, tetanus toxoid; MenA, meningococcal A; YF, yellow fever Figure 3 Freeze sensitivity of different vaccines Abbreviations: DT, diphtheria tetanus; DTP, diphtheria-tetanus pertussis; HepB, hepatitis B; Hib, Haemophilus influenzae type b; IPV, inactivated poliovirus; Td, tetanus diphtheria; TT, tetanus toxoid; YF, yellow fever Examples of these types of vaccines are bacille Calmette-Guérin (BCG), measles and rubella (MR), measles, mumps, and rubella (MMR) and rubella, which are sensitive to both light and heat. Diluents used for reconstitution of freeze dried vaccines may be stored outside the cold chain as it may occupy the space inside equipment which is necessary for storage of vaccines but at the same time, it is important that diluents are stored between +2 C to +8 C inside storage equipment/refrigerator at least 24 hours before use, i.e., reconstitution. Same temperature of vaccine and diluent prevents thermal shock to the vaccine, i.e., death of some or all the essential live organisms in the vaccine due to exposure to higher temperature leading to reduction in potency. Besides this, it is essential that only the diluent supplied by manufacturer either bundled with vaccine or separately should be used for reconstituting freeze dried vaccine, because diluents are specifically designed with respect to volume, ph level and chemical properties to suit for the needs of a particular vaccine. The physical appearance of any vaccine cannot help to decide, if it has been exposed to high or freezing temperature, or to strong light as the appearance of vaccine generally remains unchanged. Once any vaccine gets damaged due to inappropriate temperature exposures, it is not possible to regain its potency. Vaccine vial monitor (VVM) and freeze tags are generally used in cold chain to assess exposure of vaccines to higher or freezing temperature over a period of time. The details of VVM and freeze tags are as follows: Vaccine vial monitor (VVM) This is a tag containing a heat sensitive material and placed on label or on the cap of the vaccine vials (for liquid and freeze dried vaccines respectively). It is designed to register cumulative heat exposure over time during transportation and/or storage. VVM conventionally comprise of an inner lighter square placed within outer darker circle. The combined effects of temperature and duration of exposure cause the inner square of VVM to darken gradually and irreversibly. As long as inner square of VVM is lighter than the outer circle (and the expiry date has 907 SECTION 23

3 908 The Childhood Years PART V not passed) the vaccine is usable; but when color of inner square matches with that of outer circle (known as discard point) or gets darker the vaccine becomes unusable. There are four types of VVM currently in use types 2, 7, 14 and 30, each number referring to the number of days the VVM takes to reach discard point, if kept at +37 C. Different types of VVM are used to monitor different vaccines depending on their heat sensitivity. For example, VMM type 2 is assigned to OPV, which is the most heat sensitive vaccine, while VVM type 14 is assigned to DTP-Hep B, which is much less heat sensitive. VVM, however, have its limitations as it only measures exposure to high temperature and not vaccine potency, safety and exposure to freezing temperature (for freeze sensitive vaccines). Secondly, status of VVM only applies to the vaccine vial on which it is tagged, but is not applicable as a proxy indicator for other vaccines, which may have different temperature sensitivities and storage history. It is important that all workers who manage, handle and administer vaccines are well aware of different stages (usable and unusable) of VVM. Freeze indicator These are electronic and passive phase change type of devices used during internal distribution of freeze sensitive vaccines and for monitoring freezing events in cold rooms and refrigerators. The status of freeze indicator changes from good to alarm as soon as vaccine is exposed to 0.5 C for more than 60 minutes. These indicators are used to assess status of freeze sensitive vaccines. Before distributing, opening or using any vaccine, it is important to monitor status of VVM and expiry date. Vaccines whose expiry date has passed should never be used (even if VVM shows no heat damage), and on the other hand, vaccine vials whose VVM has crossed the discard point should not be used even, if they are well within the expiry date. Similarly, usable status of freeze sensitive vaccines can be determined by Shake test. This test is not routinely employed and is done only for suspected vaccine vials, to assess whether at any point of time they have been exposed to freezing temperature. Shake test compares the test vial of the vaccine which is suspected to have frozen during storage or transportation with a Control vial of the same type of vaccine and from the same manufacturer and same batch number. Control vial is prepared by storing it at 20 C overnight, and later allowed to thaw at normal room temperature. During test both Test and Control vials are vigorously shaken and placed cap side down on flat surface undisturbed for 30 minutes. The rate of sedimentation is observed in both the vials. If the rate of sedimentation in Test vial is slower than in the Control vial shows that the vaccine under test has not been damaged due to freezing. However, if the sedimentation in both vials is same or is faster in the test vial than the vaccines has been damaged and should not be used. Total period of vaccine storage at different levels of entire cold chain system is also an important factor for proper vaccine management. Suggested maximum length of storage of vaccines at national level is 6 12 months and that at subnational and district level stores is 3 months, maximum. At sub-district and health facility levels vaccines should not be stored for period of more than 1 month. Table 1 lists the recommended ranges of storage temperature for most Expanded Programme on (EPI) vaccines. COLD CHAIN EQUIPMENT There is a wide range and variety of equipment available as part of cold chain system having different capacities and features to suit the local conditions and needs. Electrical cold chain equipment includes Walk-in-Coolers (WIC), Walk-in-Freezers (WIF), Deep Freezers (DF), Ice-lined Refrigerators (ILR) and domestic refrigerators; while nonelectrical cold chain equipment are cold boxes, vaccine carriers and water-packs. There are also solar refrigerators for areas with poor or no electricity supply. Refrigerated trucks and vaccine vans are also part of cold chain system and are used for transportation in the recommended temperature ranges, which help to ensure vaccine potency from manufacturer till health facilities, outreach sessions and beneficiaries. Electrical Cold Chain Equipment Walk-in-freezers These are installed at large stores at national and subnational levels and are used to store bulk quantity of vaccine for longer period (3 months or more), maintaining temperature around 20 C. Generally, these are used for storing OPV and for preparing frozen water-packs to be used during transportation, campaigns, etc. These are available in different sizes and are provided with two cooling units and an auto-start generator for maintaining temperature in case of power failure/interruption. Along with this, WIF also have automatic temperature recording system and emergency alarm which sets on if the temperature crosses a safe range. Walk-in-coolers These are installed at national and subnational level stores and are used to store bulk quantity of vaccines at +2 C to +8 C for a longer period (3 months or more). These are used to store vaccines such as pentavalent, PCV, Rota, DTP, DT, TT, Table 1 Recommended ranges of storage temperature for vaccines Vaccines National level stores State and district level stores Health facility level OPV BCG, measles, MMR, MR, yellow fever, Hib lyophilized, meningitis, JE HepB, DTP-HepB, DTP-HepB-Hib liquid, Cholera, Hib liquid DTP, DT/TT/Td Pneumococcal, Rotavirus, HPV, Pneumococcal, Rabies, Influenza, IPV Maximum duration of storage: 6 12 months Maximum duration of storage: 3 months Store at 15 C to 25 C OPV is the only vaccine that can be safely be frozen and unfrozen repeatedly These lyophilized vaccines are to be stored at +2 C to +8 C Under exceptional circumstances, these can be temporarily stored at 15 C to 25 C (e.g., if there is temporary shortage of storage space) Diluent never to be frozen Store at +2 C to +8 C Never freeze Maximum duration of storage: 1 month Store at +2 C to +8 C Store at +2 C to +8 C Abbreviations: BCG, bacillus Calmette Guérin; DT, diphtheria tetanus; DTP, diphtheria-tetanus pertussis; MR, measles and rubella; MMR, measles, mumps, rubella; HPV, human papillomavirus; HepB, hepatitis B; Hib, Haemophilus influenzae type b; IPV, inactivated poliovirus; JE, Japanese encephalitis; OPV, oral polio vaccine; Td, tetanus diphtheria; TT, tetanus toxoid.

4 measles, BCG and Hepatitis B, etc. and similar to WIF, these also have two cooling units, autostart generator, automatic temperature recording system and emergency alarm. Deep freezers These are used at district and sub-district level and are used for storing vaccines (mostly OPV) and for preparing/freezing water-packs. In immunization program, different sizes of topopening freezers are supplied as they are able retain cool air inside better than the front opening refrigerators. Deep freezers maintain a cabinet temperature in the range between 15 and 25 C. In cases of power failure, which is very common in subdistrict level remote and rural health facilities, the special insulation of these freezers can maintain the cabinet temperature in the range of 15 to 25 C for a period up to 18 and 26 hours at external ambient temperatures of 42 and 32 C respectively, if not opened. Ice-lined refrigerators These are top opening electrical cold chain equipment available in different sizes and are used to store vaccines at district and sub-district level facilities at +2 to +8 C storage temperature (Fig. 4). These are internally lined with water containers (water-packs or tubes in different models) fitted around the walls in form of a frame. The water in these containers freeze when the ILR is functioning (or when power supply is available), and in case of power failure/interruption this ice or cold water in the containers maintain the storage temperature within the recommended range for at least 20 hours (hold over time), if not opened. This characteristic feature of ILR makes it suitable for Figure 4 Cold chain system vaccine storage even in the areas having electricity supply of as less as 8 hours. For areas with no power supply, ILRs are designed to run using kerosene, gas and also solar energy. The bottom part of the ILR is the coldest part internally and therefore vaccines which can get damaged by freezing or exposure to low temperature should not be kept in this part, especially directly on floor (Remember freeze-sensitive vaccines should never be stored within 150 mm of the base). The top part maintains the recommended temperature range and all vaccines can be stored safely in this part. As a safety measure, it is necessary to ensure during storage that none of the vaccine vials comes in direct contact with the walls or floor which can lead to freeze damage. Domestic refrigerators This can also maintain a temperature within the recommended ranges but the hold over time of these refrigerators is as little as four hours, and their capacity to freeze water-packs is also limited due to which they are generally not recommended in the immunization program. These are mostly used for vaccine storage in small health facilities and by private service providers in the urban settings where continuous power supply can be ensured. In settings where the domestic refrigerators are used for storing vaccines, it is necessary to ensure that other supplies (e.g., drugs, ointment, pathological samples, food articles and drinks) are not placed inside it and that they are exclusively used and labeled for storage of vaccines, diluents and waterpacks only. Secondly, the vaccines must not be stored in the door shelves (which are relatively warmer and gets exposed to environment temperature every time when door is opened) and in the freezer compartment (which should be used only for freezing and storing water-packs). Vaccines should be arranged in shelves from top to bottom in order of their heat sensitivity, i.e., vaccines which are more heat sensitive (e.g., OPV and measles) should be placed just below the freezer compartment, while more freezesensitive vaccines (e.g., Hepatitis B and T series vaccines) should be in the lower shelves. Diluents should also be placed next to the vaccines for which they are supplied so that they both are at the same temperature at time of distribution and this minimizes any chances of mixing up with diluents for other vaccines. Sure chill vaccine refrigerators These are new type of refrigerators which are specifically designed to maintain temperature range of 4 C 5 C for vaccines and avoid any chances of freezing and exposure to higher temperature. These are now available in two types one running on electricity (requiring just 2½ hours of power supply per day) and the other solar direct drive model (with no requirement of batteries to maintain cooling performance overnight). These refrigerators can keep vaccines safe for up to 10 days at 32 C ambient, and even longer at lower temperature. Solar refrigerators These are freezer cum refrigerators with two separate compartments, one having basket for storing vaccines (maintains temperature at +2 C to +8 C) and other for freezing water-packs (with temperature at 15 C to 25 C). These refrigerators run on the same principle as normal compression refrigerators but involve low voltage DC compressors and motors (12V or 24V). Normally, the batteries can store solar energy for 5 days. It is important to clean the solar panel on a periodic basis for removing dirt, soot, smog and debris, as shading of as less as 10% of panel area with dirt or bird droppings can reduce power output by 50% (similar to that of a cloudy day). Automatic voltage stabilizer This is an important part of cold chain system, which corrects the fluctuations in the main voltage and maintains it in range of 220 ± 10 V, which is necessary for ensuring correct storage temperature. Each electrical refrigeration equipment should necessarily be connected to a separate dedicated mains supply via a separate functional stabilizer at all levels of the cold chain. Different types of voltage stabilizers used 909 SECTION 23

5 910 The Childhood Years PART V in cold chain system are as follows: servo-mechanical voltage stabilizers recommended for areas with mains voltage range variation up to 50%; electronic voltage stabilizers for equipment requiring extremely fast correction speed and those located in hostile climatic conditions; and tap changing voltage stabilizers recommended for less sensitive equipment. Nonelectrical Cold Chain Equipment Cold boxes These are big insulated boxes mainly used for transportation of vaccines (and diluents) and also for storing vaccines in case of power failure or equipment breakdown. These are available in different sizes such as 5, 8, 20 and 22 liters depending on the storage capacity and are supplied with requisite number of water-packs. A 5 and 8 liter cold box can store 1,500 and 2,400 doses of mixed antigens respectively. Vaccines are placed in cartons or polythene bags inside the cold box and while arranging vaccines either for storage or transportation it is essential to ensure that OPV and single antigen lyophilized vaccines (those packed with frozen water-packs) are placed separately from freeze sensitive and multivalent vaccines (those packed with cool water-packs). After placing vaccines, frozen/cool water-packs are arranged over top of vaccines and diluents and covered with plastic sheet for ensuring full hold over time. Freeze indicator should also be placed inside cold box to monitor that the storage temperature has not dropped below 0 C. In order to maintain proper functioning of cold boxes, it is essential that after every use they are examined both internally and externally for any cracks, rubber seal around the lid is checked, hinges and locks are lubricated periodically and are kept unlocked and opened while not in use. Vaccine carriers These are insulated boxes used to carry small quantities of vaccines and diluents (approximately vials) to immunizations sessions in the outreach areas. These are supplied with four water-packs and a foam pad to cover vaccines from top and maintain the storage temperature. Vaccine carriers should be packed with mix of vaccines and diluents with cool water-packs in order to prevent damage to freeze sensitive vaccines. The diluents (and droppers as for OPV) should be packed with vaccines for transportation to outreach sites, taking care that diluents does not come in direct contact with the frozen/conditioned water-packs. Vaccine carriers should be wiped and cleaned dry both from inside and outside each time after use and stored with lid opened. Water-pack (Ice-pack) These are flat plastic containers, filled with fixed quantity of water (0.3 L, 0.4 L and 0.6 L depending on size and manufacturer) and are prepared as frozen water-pack (for storage and transportation of OPV and single antigen freeze dried lyophilized vaccines), cool water-pack (for transportation of liquid vaccines other than OPV) or a warm water-pack (stabilized at room temperature between +10 C and +24 C and used for transportation of freeze-sensitive vaccines for a period up to 8 hours). The waterpacks frozen inside deep freezer have a surface temperature of 15 C to 25 C, which can cause freeze damage particularly to freeze-sensitive vaccines during transportation. Therefore, before packing frozen water-packs, they are kept in open at room temperature until the ice within it which is in contact with the walls melts. This process is known as conditioning of water-packs and the time required for melting some ice depends on the ambient temperature and can take up to 30 minutes. MONITORING OF COLD CHAIN Monitoring of cold chain is an indispensable part of entire cold chain system and it helps to ensure that adequate number of type of cold chain equipment are available and functioning, vaccine supply is timely and adequate, storage temperatures and other conditions are as recommended and that all vaccines are potent and safe to use. Temperature Monitoring Devices Fixed dial thermometer These are used to measure temperature inside ILR and DF and can show the temperature in the range of 50 C to +50 C. Bimetallic dial thermometers are no longer used because they easily loss their calibration. Alcoholic stem thermometer These thermometers are more sensitive and accurate than dial thermometers and can record the same temperature range. These can be used in all types of refrigerators and freezers; however, since they do not provide a continuous record of vaccine temperature exposure therefore they should not be used as primary temperature monitoring device. Electronic data logger This is an electronic device which is placed within the vaccine vials and record temperature for a period of 30 days. This is equipped with alarm system which alerts the handlers whenever the storage temperature crosses the safe range. These are specifically designed to be used in ILRs and WICs which are required to maintain the temperature between +2 and +8 C. Vaccine Management: Storage and Distribution It is necessary to ensure that at any point of time, sub-district level cold chain facility has adequate quantity of vaccines estimated as per requirement for the catchment area for a particular period of time. In addition to monthly requirement, a designated buffer stock of each vaccine (25% of monthly requirement) should also be available to meet extra demand or any delay in supply. Estimate of requirements for each different vaccine should be done for the catchment area on periodic basis and the quantity of any particular vaccine should be requested/indented depending on the number of beneficiaries in the area, number of doses required for a vaccine by one beneficiary to complete immunization schedule and the wastage factor for that vaccine. General guidelines for storage of vaccines are as follows: All vaccines stored in ILR should be placed in baskets (supplied with equipment) in separate labeled boxes for easy identification and with adequate space between them for air circulation (2 cm space on all sides and between boxes). The boxes should also have holes to facilitate good access to cool air. In case basket is not available vaccine boxes should be kept over two layers of empty water-packs placed to prevent direct contact with the floor (also prevents boxes to get wet by water collected at bottom). Every cold chain equipment should have one thermometer placed in basket with vaccines or between the vaccine boxes for twice daily monitoring of storage temperature. Care should be taken that thermometer is placed in contact with the walls. Freeze sensitive vaccines and those with close expiry should be kept on top in ILR basket (and front in front opening refrigerators) so that they are utilized first. Diluents should not be frozen or stored inside deep freezer as these ampoules are not designed for freezer storage and can crack. Food items, drinks, other drugs and vaccines not included in national immunization program should not be stored in equipment (electrical or nonelectrical) in which vaccines are stored. Cold chain equipment should be plugged directly into the wall outlets, with a label Do not unplug. Alternatively, plug guards or safety-lock plugs can be used to prevent inadvertent unplugging of the equipment. Every equipment should be defrosted and cleaned at least once every month or when the frost on inner walls is more than 0.5 mm. At time of defrosting vaccines should be shifted to other equipment or in cold boxes with adequate number of cool water-packs.

6 Proper record keeping is crucial for ensuring quality cold chain system and separate date-wise records of vaccine receipts, distribution and balance sheets should be available for each type of vaccine and vaccine product. Other information to be recorded and updated include the date of receipt, name of manufacturer, batch number, manufacture and expiry date, VVM status and any other information available for ensuring the quality and potency of vaccines and vaccine products. Vaccine inventory control For ensuring adequate and effective immunization coverage in an area, it is important that availability of vaccine stock is ensured at all times. A vaccine inventory should be conducted on monthly basis to ensure adequate supply for meeting demand. Diluents are also a part of inventory and it is essential that they are available in adequate supply. Factor which determine the requirement of vaccines and diluents are projected demand, storage capacity, and current vaccine supply. Problems generally encountered with respect to stock position include inadequate stock (amount available is less than the buffer stock, i.e. 25% of monthly requirement), stock out (when a particular vaccine or vaccine product is not available) and excess stock (when available stock is more than 1 month requirement and buffer stock, i.e. more than 125%), which leads to vaccine wastage or outdated vaccines in hand. to inappropriate storage conditions. To dispose vaccines in these different forms medical waste disposal procedures outlined in national level policies and guidelines must be followed. IN A NUTSHELL 1. Effective cold chain network is most essential to ensure quality immunization services. 2. Temperature ranging from +2 C to 8 C is generally safe for storage of nearly all the vaccines. 3. Sunlight and fluorescent (neon light) can also cause loss of potency of the vaccines. 4. A wide range of equipment is available for the cold chain system having different capacities and features to suit different local conditions and needs. 5. It is important to monitor the expiry date and VVM (where applicable) before distributing, opening or using these vaccines. 6. All vaccines stored in the cold chain equipment should have separate labeled boxes for easy identification and adequate space between them for air circulation. 7. Proper record-keeping is crucial for ensuring quality cold chain system. 911 SECTION 23 GUIDELINES FOR USE OF OPENED MULTIDOSE VIALS Earlier it was generally followed that all vaccine vials opened for an immunization session were discarded at the end of session, irrespective of the type of vaccine or the remaining number of doses. However, for vaccines including OPV, DTP, TT, DT, Hepatitis B and liquid Hib revised policy has been instituted by WHO provided that these vaccines meet WHO requirements for potency and temperature stability, are packaged according to ISO standards and contain and appropriate concentration of preservative (e.g. thiomersal for injectable vaccines only). For these vaccines revised policy states that: Multidose vials of OPV, DTP, TT, DT, Hepatitis B and liquid formulations of Hib vaccines from which one or more doses of vaccines have been removed during an immunization session may be used in subsequent immunization sessions for up to a maximum of 4 weeks, only when the following conditions are met: The expiry date has not passed The vaccines are stored under appropriate cold chain conditions The vaccine vial septum has not been submerged in water Aseptic technique has been used to withdraw all doses VVM (if attached) has not reached the discard point. The revised policy does not change recommended procedures for handling vaccines that require reconstitution, i.e. BCG, measles, yellow fever and some formulations of Hib vaccine. These vaccines once reconstituted, vials must be discarded at the end of immunization session or at the end of recommended period of use whichever comes first. As per WHO guidelines, reconstituted vaccines should not be used beyond 6 hours of time of reconstitution. In India s Universal Programme, BCG, measles and Japanese encephalitis (JE) are the vaccines which require reconstitution, out of these reconstituted BCG and measles are not to be used beyond 4 hours and Japanese encephalitis (JE) vaccine not beyond 2 hours from the time of their reconstitution. Vaccine disposal There are situations when the vaccine vials and other vaccine products need to be terminally disposed and there are specific guidelines for disposal of unopened unexpired vials, expired vials, opened vials with unused doses, doses drawn but not administered and potentially compromised vaccines resulting due MORE ON THIS TOPIC CDC. Vaccine Storage and Handling; Epidemiology and Prevention of VPDs. Atlanta: CDC; Handbook for Vaccine and Cold Chain Handlers. New Delhi: Ministry of Health & Family Welfare, Government of India; WHO. PQS Devices Catalogue, Pre-qualified equipment for the Expanded Programme on. Geneva: WHO; WHO. The use of opened multidose vials of vaccine in subsequent immunization sessions. WHO Policy Statement. Geneva: World Health Organization; WHO. Training for Mid-level Managers, Module 1: Cold Chain, vaccines and safe injection equipment management. Geneva: WHO/IVB, World Health Organization; Chapter 23.5 Adverse Events Following Ajay Kalra An adverse event following immunization (AEFI) is defined as medical incident that takes place after immunization, causes concern, and is believed to be caused by immunization. The event can be a true adverse event or an event coincidental to the immunization. AEFIs are classified into the categories given in Table 1. VACCINE REACTIONS The vaccine can cause adverse events due to its inherent properties. They are usually of two types: (a) Minor reactions and (b) Serious reactions. Most vaccine reactions are minor and settle down on their own. Minor reactions are more common. They can be local like pain swelling and/or redness at injection site or systemic such as fever, vomiting, malaise which can result from the normal immune response to the vaccine. Serious reactions are rare. They can be in the form of seizures, encephalopathies [as in pertussis and measles, mumps, and rubella