Ask the Experts: Storage & Handling: Temperature Monitoring & Controls

Results (10)

Every vaccine storage unit must have a temperature monitoring device (TMD). CDC recommends that vaccines be monitored using a “digital data logger” (DDL). A DDL provides the most accurate storage unit temperature information, including a detailed record of how long a unit has been operating outside the recommended temperature range (referred to as a “temperature excursion”). Unlike a simple minimum/maximum thermometer, which only shows the coldest and warmest temperatures reached in a unit, a DDL provides a log of the temperature recorded at preset intervals (at least every 30 minutes is recommended).

Many DDLs use a buffered temperature probe, which is the most accurate way to measure actual vaccine temperatures. Temperatures measured by a buffered probe match vaccine temperatures more closely than those measured by standard thermometers, which tend to reflect only air temperature. Temperature data from a DDL can either be downloaded to a computer using special software or retrieved from a website. The software or website may also allow you to set the frequency of temperature readings. Reviewing DDL data regularly is critical to ensure temperature excursions that could damage vaccines do not go on without being addressed. It is important to decide whether independent software or a website program works best for your facility.

Temperature monitoring devices that are NOT recommended include alcohol or mercury thermometers, even if placed in a fluid-filled, biosafe, liquid vial; bimetal stem devices; devices used for food; chart recorders; infrared devices; and devices that do not have a current and valid Certificate of Calibration Testing. Please note that some devices sold in hardware and appliance stores are designed to monitor temperatures for household food storage. They are not calibrated and not accurate enough to ensure vaccines are stored within the correct temperature range. Using these devices can pose a significant risk of damaging vaccines due to undetected out-of-range temperatures.

More details on temperature monitoring are available on pages 10–11 of CDC Vaccine Storage and Handling Toolkit, available at www.cdc.gov/vaccines/hcp/admin/storage/toolkit/storage-handling-toolkit.pdf. Additional details about temperature monitoring for COVID-19 and mpox vaccines are available in the addendum at the end of the toolkit.

Last reviewed: July 26, 2023

CDC recommends that you use only a temperature monitoring device (TMD) with a Certificate of Calibration Testing (also known as a Report of Calibration). This certificate provides the TMD’s level of accuracy compared to a recognized standard. This certificate comes with the TMD when it is purchased, and it is different than the manufacturer’s warranty. While all TMDs are calibrated during manufacturing, certified calibrated TMDs undergo a second individual calibration against a reference standard from an accredited testing laboratory. Calibration testing should be done every 2 to 3 years or according to the manufacturer’s suggested timeline to ensure the accuracy of the device continues to conform to nationally accepted standards. Additional information on this topic is available on page 11 of CDC’s Vaccine Storage and Handling Toolkit, available at www.cdc.gov/vaccines/hcp/admin/storage/toolkit/storage-handling-toolkit.pdf.

Last reviewed: July 26, 2023

A buffered temperature probe is designed to prevent misleading and rapidly fluctuating readings by protecting the TMD from sudden changes in air temperature that can occur when opening a refrigerator door. A probe is “buffered” by immersing it in a vial filled with liquid (e.g., glycol, ethanol, glycerin), loose media (e.g., sand, glass beads), or a solid block of material such as Teflon or aluminum. Vaccine packaging is more thermostable than air because the temperature of solids and fluids change more slowly than air. Standard probes that measure air temperature can fluctuate with the defrost cycles of the unit, frequent opening and closing the door on busy workdays, air circulation patterns, etc. This could lead someone to inaccurately interpret changes in air temperature to mean that the vaccine temperature was out of range.

Last reviewed: July 26, 2023

No. CDC recommends that every vaccine storage unit must have its own TMD. An accurate temperature history that reflects actual vaccine temperatures is critical for protecting your vaccines. It is also recommended to have at least one backup TMD on site in case a primary device breaks or malfunctions.

Last reviewed: July 26, 2023

It may take 2 to 7 days to stabilize the temperature in a newly installed or repaired refrigerator or 2 to 3 days for a freezer. Before using a unit for vaccine storage, check and record the minimum and maximum temperatures each workday for two to seven days. If temperatures cannot be recorded using a continuous digital data logger, check and record temperatures a minimum of two times each workday. Once you have two consecutive days of temperatures recorded within the recommended range, your unit is stable and ready for use. Recommended temperatures are between 2°C and 8°C (36°F and 46°F) for the refrigerator and between -50°C and -15°C (-58°F and +5°F) for the freezer.

Last reviewed: July 26, 2023

Check and record storage unit minimum and maximum temperatures for the time since last measurement at the start of each workday. This is a requirement for VFC providers. The minimum and maximum temperatures recorded should be those obtained since the last workday when the minimum and maximum temperatures were reset. If your device does not display minimum and maximum temperatures, then check and record the current temperature a minimum of 2 times (at the start and the end of the workday). This should be done even if there is a temperature alarm at some point during the day.

Last reviewed: July 26, 2023

If the vaccine cold chain is broken, the ambient room temperature is useful information in helping determine how to handle the compromised vaccine. Do not remove the calibrated thermometer from the refrigerator or freezer to measure the room temperature. A standard household thermometer in the room is fine for this purpose.

Last reviewed: July 26, 2023

CDC recommends that refrigerator and freezer temperature logs be kept for at least 3 years. See page 10 of the Vaccine Storage and Handling Toolkit, available at www.cdc.gov/vaccines/hcp/admin/storage/toolkit/storage-handling-toolkit.pdf. The reasoning is that it is useful to be able to look back at the record to help determine if a unit is developing a problem.

Individual state Vaccines For Children (VFC) programs may have additional requirements for retaining temperature logs. You should contact your state program for this information. Contact information for state immunization programs is available at www.immunize.org/coordinators.

Last reviewed: July 26, 2023

Vaccines from your supply should not be routinely transported. In instances where the transport of vaccine from your supply is necessary, take appropriate precautions to protect your supply. Vaccines should only be transported using appropriate packing and temperature monitoring materials that provide the maximum protection. CDC provides detailed guidance on the transport of vaccines in the Storage and Handling Toolkit, pages 23–26 at www.cdc.gov/vaccines/hcp/admin/storage/toolkit/storage-handling-toolkit.pdf. See the addendum of the Toolkit for additional instructions concerning COVID-19 and mpox vaccines.

Last reviewed: July 26, 2023

CDC has included in the Vaccine Storage and Handling Toolkit an addendum that contains additional details concerning special considerations for COVID-19 and mpox vaccines. This is available at www.cdc.gov/vaccines/hcp/admin/storage/toolkit/storage-handling-toolkit.pdf.

Last reviewed: July 26, 2023

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