CDC offers detailed recommendations in regards to the proper storage and handling of vaccines. These recommendations aim to help healthcare providers store, handle, and administer vaccines efficiently and effectively in order to protect patients and the population from devastating diseases. These recommendations are driving providers away from storing vaccines in a household or commercial refrigerator, and towards the use of medical-grade cold storage solutions. However, there is a major difference in performance between many “medical-grade” refrigerators on the market.
Temperature Uniformity
CDC specifically recommends performing various temperature readings inside of your refrigerator to locate the most stable area for storing vaccines. At Helmer, we refer to this testing as temperature mapping. Temperature mapping is an important part of determining how safe your refrigerator is for vaccine storage.
When creating a temperature map, all areas within a medical-grade refrigerator should reflect a uniform temperature with variations less than or equal to +/-1.5° C. When performing temperature mapping on a household or commercial unit, you will most likely find that temperatures throughout the unit vary immensely. In this type of unit the only safe area for vaccine storage is often in the middle of the refrigerator away from walls, ceilings, cooling vents, doors, the floor, and the back of the unit. It is likely that all other locations inside the refrigerator may expose vaccines to warm or freezing temperatures putting their efficacy at risk. This poor uniformity leaves little usable storage space. Refrigerators that do not provide a uniform storage environment throughout are not true medical-grade.
Temperature Recovery
CDC stresses the importance of not letting the refrigerator door stand open unnecessarily. This negatively affects temperature in the unit and may cause the unit temperature control to respond to the warmer air temperature in the room. Higher temperature may cause the unit to work harder and overcompensate cooling making some areas of the unit prone to freezing. This tends to be a major problem with household and commercial units. They are not designed to quickly recover to set temperature after the door is shut leaving vaccines at risk.
Medical-grade refrigerators are designed to quickly recover to set temperature after door openings, ensuring that vaccine temperatures are not affected by users opening and closing the refrigerator door many times throughout the day. These units may also have a self-closing door and an open door alarm to help prevent temperature excursions from occurring.
An Evaluation of Two Refrigerators
Many manufactures of refrigerators and freezers are aware of the increasing demand for high performing, medical-grade refrigeration. To capitalize on this demand, they have enhanced household and commercial units to appear as if they provide superior storage for vaccines, medications, and samples. Many of these units provide a similar storage environment to a household or commercial refrigerator. Ask your refrigerator manufacturer if they are able to provide temperature mapping data (uniformity data) and recovery data that reflects medical-grade performance.
To highlight the importance of storing vaccines in a true medical-grade refrigerator a side-by-side comparison of the Helmer Scientific medical-grade under-counter refrigerator and the CliniCool 5.2 cu ft. under-counter refrigerator was conducted. This evaluation included measurement of temperature uniformity across multiple locations in the refrigerator cabinet, temperature recovery after short and extended door openings, and temperature recovery time (pull-down test) from ambient to simulate power loss.
