Ask the Experts: Storage & Handling: Vaccine Storage Units

Never! A “dormitory-style” refrigerator is a small combination refrigerator/freezer unit that is outfitted with one exterior door and an evaporator plate (cooling coil), which is usually located inside an icemaker compartment (freezer) within the refrigerator. Dormitory-style (bar-style) units pose a significant risk of freezing vaccine even when used only for temporary storage. During testing, dormitory-style refrigerators demonstrated consistently unacceptable performance, regardless of where the vaccine was placed inside the unit. The use of dormitory-style refrigerators is specifically prohibited for storage of VFC vaccines or other vaccines purchased with public funds.

A “dormitory-style” refrigerator is a small combination refrigerator/freezer unit that is outfitted with one exterior door and an evaporator plate (cooling coil), which is usually located inside an icemaker compartment (freezer) within the refrigerator. This type of unit has severe temperature control and stability issues. However, there are compact refrigerators or freezers noted as “pharmaceutical grade” or “purpose-built for vaccine storage” that have been engineered to maintain even temperatures throughout the unit, and these may meet the needs of a small office. In general, the unit you select must be large enough to store the year’s largest vaccine inventory without crowding and to store water bottles (in a refrigerator) and frozen coolant packs (in a freezer) to minimize temperature fluctuations. One way to assure that the unit you purchase will reliably maintain proper vaccine storage temperatures is to look for a unit labeled as meeting the NSF/ANSI 456 certification standard for vaccine storage. This voluntary certification indicates that the model has been tested and certified to maintain proper storage conditions under a range of normal clinic conditions.

Stand-alone units that only refrigerate or only freeze are recommended by CDC. Household-style combination refrigerator/freezer units are less capable of simultaneously maintaining proper storage temperatures in both compartments. In addition, some areas of the refrigerator space may also be unusable due to uneven temperatures in the refrigerator section interior. If a household-style combination refrigerator/freezer must be used, only refrigerated vaccines should be stored in the unit: a separate stand-alone freezer should be used if the clinic also provides frozen vaccines. Pharmaceutical grade combination units designed for vaccine storage may be acceptable for use because they are engineered not to circulate air from the freezer directly into the refrigerator compartment in the way that a household-style unit does. Stand-alone units can vary in size from compact, under-the-counter (not dormitory) style to large, stand-alone, pharmaceutical grade units (which may be labeled as purpose-built for vaccine storage). For additional information see the CDC Storage and Handling Toolkit, page 9, at www.cdc.gov/vaccines/hcp/admin/storage/toolkit/storage-handling-toolkit.pdf.

One way to have confidence that the refrigerator or freezer unit you purchase will reliably maintain proper vaccine storage temperatures is to look for a unit labeled as meeting the NSF/ANSI 456 standard for vaccine storage. This voluntary certification indicates that the model has been tested and certified to maintain proper vaccine storage conditions under a range of normal clinic conditions.

Yes. Vaccines that are stored in the refrigerator portion of a household-style combination refrigerator/freezer should be moved away from the vent located in the refrigerator compartment. The cold air from the freezer is circulated into the refrigerator compartment to cool it, which can cause your vaccines to freeze. Inactivated vaccines must be kept between 2° and 8°C (between 36° and 46°F) and not frozen.

Generally speaking, CDC recommends avoiding the top shelf and the areas near vents due to temperature fluctuations. However, most purpose-built or pharmaceutical-grade units use a fan to circulate air within the storage area and create more uniform temperatures than household units. During a power outage, the top shelf is an area of caution for all units as the temperatures increase most quickly there. In this instance, it would be best to check with the manufacturer or owner’s manual to see if the top shelf is appropriate for storage in your unit. Units that meet the NSF/ANSI 456 voluntary certification standard are designed to deter the user from placing vaccines in areas where proper storage temperatures cannot be maintained, so any shelf available storage in a certified unit would be usable.

No. If you turn off the freezer portion of a household-style combination refrigerator/freezer, the refrigerated compartment will not maintain the proper temperature.

Vaccines should not be stored in vegetable bins nor in the space occupied by vegetable bins of a household-style refrigerator. This area is commonly closer to the motor of the unit and the temperature is different from that in the body of the refrigerator. We recommend that you remove the vegetable bins and put bottles of water in that space to help maintain a constant temperature in your refrigerator. Vaccines should be placed in the center of the refrigerator, away from the walls and floor of the unit in open containers so air can circulate around the vaccines. If using the refrigerator section of a household-style combination refrigerator/freezer unit, you do not want the top storage shelf in the refrigerator to be too close to the vent that comes from the freezer because this can expose your vaccines to freezing temperatures.

No vaccine component, including the diluent used to reconstitute a vaccine, should be stored in vegetable bins, nor in the space occupied by vegetable bins of a household-style refrigerator. CDC recommends that you position vaccines and diluents 2 to 3 inches from the unit walls, ceiling, floor, and door. If using a household-style unit, avoid storing vaccines and diluents in any part of the unit that may not provide stable temperatures or sufficient air flow, such as directly under cooling vents; in deli, fruit, or vegetable drawers; or on refrigerator door shelves. The instability of temperatures and air flow in these areas may expose vaccines to inappropriate storage temperatures. For more information, refer to page 14 of the CDC Vaccine Storage and Handling Toolkit available at www.cdc.gov/vaccines/hcp/admin/storage/toolkit/storage-handling-toolkit.pdf.

No, do not use the same unit. Frequent opening of the refrigerator door to retrieve food items can adversely affect the internal temperature of the unit and potentially damage the vaccines.

CDC recommends using separate refrigerator and freezer units for vaccine storage, but still allows use of a combination refrigerator/freezer if you only use the refrigerator portion for storing vaccines (as you are doing). CDC also recommends that you store food and beverages in a separate storage unit from vaccines, which you are technically doing, but there may still be an impact on the refrigerator temperature by the opening and closing of the freezer door by staff. (In most two-compartment units, cold air from the freezer is circulated for cooling the refrigerator.)

The best situation would be to get a stand-alone pharmaceutical/purpose-built refrigerator unit for your vaccines (consider one that meets the voluntary NSF/ANSI 456 certification for vaccine storage), and use your refrigerator/freezer combination unit for your food and drinks. For more information about storage unit features and recommendations, refer to pages 9 and 31 of the CDC Vaccine Storage and Handling Toolkit available at www.cdc.gov/vaccines/hcp/admin/storage/toolkit/storage-handling-toolkit.pdf.

CDC’s Vaccine Storage and Handling Toolkit states that if other medications and biological products must be stored in the same unit as vaccines, they must be clearly marked and stored in separate containers or bins from vaccines. Potentially contaminated items (e.g., blood, urine) should be properly contained and stored below vaccines due to risk of contamination from drips or leaks. The freezer of a household-grade unit may be used for non-vaccine, medical storage, so long as the use does not compromise the temperature range within the refrigerator compartment where vaccine is stored.

A refrigerator or freezer that is NSF-certified for vaccine storage means the units have been tested and certified to meet the NSF/American National Standards Institute (ANSI) 456 standard. The NSF/ANSI 456 standard (or simply “NSF 456” standard) defines the criteria for construction and performance of vaccine refrigerators and freezers used in healthcare settings where vaccines are given. These criteria were developed through a collaboration with NSF, CDC, healthcare providers, public health agencies, equipment manufacturers, and vaccine manufacturers, including experts from Immunize.org.

The NSF 456 certification is a voluntary standard. CDC does not require NSF-certified units for vaccine storage in the Vaccines for Children program or any other federal program. Not all storage units capable of reliably storing vaccines have this certification; however, all storage unit models with this certification have been designed and proven to properly store vaccines under a range of normal clinic conditions. NSF-certified units would be good options for clinic staff to consider when purchasing vaccine storage units.