We are often asked if lab or pharmacy refrigerators can be used for storing vaccines… and the answer to that depends on how the vaccines are packaged and positioned inside the refrigerator.

A lab or pharmacy refrigerator is designed to keep product at 4-5C (39-41F), but the amount of liquid per container/package being stored is generally quite large compared to the amount of liquid in a vaccine. Air temperature variation in a lab/pharmacy refrigerator can range from 1 to 9C per cycle (or higher, if the fridge has an automatic defrost cycle periodically heating the refrigeration coil), while maintaining temperature inside a 250 ml bag of stored liquid at setpoint temperature, plus or minus 1C. A relatively large mass of liquid responds slowly to temperature variations. Because the vaccines have a considerably smaller thermal mass, it is critical to store them in a refrigerator designed to keep air temperature variation tightly controlled to 2-8C throughout and to monitor the temperature with an e-mail or phone activated alarm system.

But… vaccine storage refrigerators are expensive, so vaccines are often stored in lab or pharmacy refrigerators…even household refrigerators…with the assumption that the variation in temperature shown on the temperature controller is the same as the variation in temperature throughout the chamber. This may be nearly the case in a small undercounter-sized refrigerator, but in larger chambers, the variation can be twice as much as the control sensor indicates – or more. To keep vaccines safe and effective in refrigerators not designed for tight temp control, the solution is to map the refrigerator over a few days time with temperature sensors placed on each shelf in several positions. (Search “validation services” to find help with mapping in your geographical area.) If a position can be found where the temperature always stays within 2-8C (36-46F), that position can be used to store vaccines. Follow CDC recommendations for bundling the vaccines together in their original packages to increase their thermal mass and fill the refrigerator with bottles of water along the left and right hand walls from top to bottom to increase the chamber temperature stability (and save electricity). Finally, if a lab or pharmacy refrigerator is used for vaccine storage, capture the temperature data on a chart recorder (small battery operated ones are readily available) and monitor the temperature with a temperature alarm placed at the vaccine location (see Sensaphone.com).

Once you know what it takes to store vaccines properly, you might want to see proof that your next inoculation, or that of a loved one, has been handled responsibly!