This section does not address the special storage and handling conditions for the frozen mRNA COVID-19 vaccines; please see the COVID-19 section of Ask the Experts (www.immunize.org/askexperts/experts_cov.asp) and our Vaccines: COVID-19 main page (www.immunize.org/covid-19) for questions and answers about the storage and handling of these vaccines.
The Centers for Disease Control and Prevention (CDC) provides comprehensive information about vaccine storage and handling in their Storage and Handling Toolkit, available at www.cdc.gov/vaccines/hcp/admin/storage/toolkit/storage-handling-toolkit.pdf. The toolkit was revised in 2021 with an addendum addressing COVID-19 vaccines.
Vaccine Storage Units
When is a "dormitory style" refrigerator considered adequate for storing vaccines?
Never! 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.
We have a small office with limited space for a vaccine storage unit. If dormitory-style refrigerators are not an option, what can we use?
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, compact "purpose built" or "pharmacy grade" refrigerators and freezers that have been engineered to maintain even temperatures throughout the unit are available, and these may meet the needs of a small office. In general, the unit 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 temperatures fluctuations.
Our office is committed to assuring appropriate storage for our vaccines. Do we need a stand-alone refrigerator and freezer, or is a combination unit adequate?
Stand-alone units that only refrigerate or only freeze are recommended by CDC. 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 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. Stand-alone units can vary in size from compact, under-the-counter (not dormitory) style to large, stand-alone, pharmaceutical grade units. For additional information see the CDC Storage and Handling Toolkit, page 8, at www.cdc.gov/vaccines/hcp/admin/storage/toolkit/storage-handling-toolkit.pdf.
There is a vent in our combination refrigerator/freezer that brings in cold air from the freezer. Vaccines stored near this vent are colder to the touch. Could this be a problem?
Yes. Vaccines that are stored in the refrigerator portion of a 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.
Is the top shelf of a pharmacy-grade storage unit acceptable for vaccine storage if there is a fan directly above it?
Generally speaking, CDC recommends avoiding the top shelf and the areas near vents due to temperature fluctuations. However, most 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.
Since I am no longer storing frozen vaccines in the freezer portion of my combination refrigerator/freezer, should I just turn off the freezer portion of the unit?
No. If you turn off the freezer portion of a combination refrigerator/freezer, the refrigerated compartment will not maintain the proper temperature.
We have a large quantity of vaccines, and space is always an issue. Since you cannot put vaccines in the vegetable bins, can we remove them and then put vaccines in that space?
Vaccines should not be stored in vegetable bins or 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 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.
Can we store vaccine in the same unit where we store employees' lunches?
No, don't 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.
Our office is small and we only store vaccine in the refrigerator of a combination refrigerator/freezer. Can we use the freezer portion to store staff food?
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 ideal situation would be to get a stand-alone pharmaceutical/purpose-built refrigerator unit for your vaccines, and use your refrigerator/freezer combination unit for your food and drinks. For more information about storage unit features and recommendations, refer to pages 8 and 29 of the CDC Vaccine Storage and Handling Toolkit available at www.cdc.gov/vaccines/hcp/admin/storage/toolkit/storage-handling-toolkit.pdf.
Is it okay to store medications and other biologic products in the same unit as vaccines?
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.
Can you please guide me in finding storage containers and bins for vaccines?
CDC recommends the use of bins, baskets, or some other type of uncovered containers that allow for organization and air circulation for vaccines and diluents within the storage unit. Storage in boxes or bins can help maintain temperature longer, especially if power is lost. Perforated bins may allow for better air circulation around the vaccine, thus helping to maintain correct temperature.
CDC does not have a specific recommendation for brands of containers or bins for storage of vaccine. We recommend that you contact your state immunization program, as they may have suggestions for purchasing this equipment. If you are a Vaccines for Children (VFC) program provider, you should contact your immunization program to ensure that you are in compliance with VFC policy.
Temperature Monitoring & Controls
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What type of device should be used for measuring temperatures in a vaccine storage unit? What types of temperature monitoring devices should NOT be used for this purpose?
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 (see next question). 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.
More details on temperature monitoring are available on pages 9–10 of CDC Vaccine Storage and Handling Toolkit, available at www.cdc.gov/vaccines/hcp/admin/storage/toolkit/storage-handling-toolkit.pdf.
What is a certificate of calibration testing?
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. Additional information on this topic is available on page 10 of CDC's Vaccine Storage and Handling Toolkit, available at www.cdc.gov/vaccines/hcp/admin/storage/toolkit/storage-handling-toolkit.pdf.
Why does the temperature probe of a temperature monitoring device (TMD) need to be suspended in a buffer? Won't it work just as well if it is measuring air temperature?
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.
How long should we monitor the temperature in a new refrigerator before storing vaccines in it?
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 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.
How often should temperatures be checked and recorded on our vaccine storage unit's log?
Check and record storage unit minimum and maximum temperatures 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 end of the workday). This should be done even if there is a temperature alarm.
Why should I record the temperature of the room where the vaccine storage unit is located?
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.
How long do we need to keep our refrigerator/freezer temperature tracking logs?
CDC recommends that refrigerator and freezer temperature logs be kept for at least 3 years. See page 9 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.
Please provide guidance for transporting our vaccine to an off-site location.
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 materials that provide the maximum protection. CDC provides detailed guidance on the transport of vaccines in the Storage and Handling Toolkit, pages 21–24 at www.cdc.gov/vaccines/hcp/admin/storage/toolkit/storage-handling-toolkit.pdf.
Troubleshooting & Follow-Up
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We use a digital data logger and are carefully logging our vaccine storage unit's temperatures each day. Is there anything else that could go wrong?
Congratulations on your hard work! You would be surprised at the number of people who, just like you, do a careful job of recording temperatures, but then they fail to act on them when the temperatures go out of range. Always take immediate action when you notice an out-of-range temperature. You may need to move the vaccines temporarily to a more reliable storage unit and determine the source of the problem. It may be something quite fixable (e.g., excessive lint or dust on the coils), and you will be back in business after you determine that the temperature is back in range after a few hours.
Above all, don't chart an out-of-range temperature and not act on it! IAC has created temperature recording logs and a troubleshooting record to document unacceptable vaccine storage events. The CDC Storage and Handling Toolkit contains detailed guidance on the management of a temperature excursion. See pages 12–15 at www.cdc.gov/vaccines/hcp/admin/storage/toolkit/storage-handling-toolkit.pdf.
One morning, our refrigerator temperature monitoring device registered 32° F. The vaccine didn't look frozen so we kept using it. Was this okay?
No. If you find that a vaccine has been exposed to an inappropriate temperature, try to determine the reason for the temperature excursion, mark the vaccine "Do Not Use," and contact the manufacturer or the state or local health department to determine if the vaccine can be used.
Do not leave vaccines in a storage unit that does not maintain temperatures within the recommended range. If you are unable to stabilize the temperature in your unit within the required range, or temperatures in the unit are consistently at the extreme high or low end of the range, identify an alternative unit with appropriate temperatures and sufficient storage space until the primary unit can be repaired or replaced.
What should I do if my temperature monitoring device indicates my refrigerated vaccine has been stored between 32° and 34°F? Since the vaccine wasn't "frozen," will it be OK to use? And what about people who received the vaccine before we discovered the temperature excursion—will we need to revaccinate them?
This is a complex question that requires case-by-case review. First, while you're assessing the situation, return the vaccine to proper storage temperatures and mark it "Do Not Use." Then, contact your state or local immunization program or the appropriate vaccine manufacturer(s) to discuss the potential usability of the vaccine. They will need to consider several variables related to vaccine storage conditions. For example, their guidance will be affected by the type and accuracy of the temperature monitoring device, whether the temperature probe was in a liquid or was reading the temperature of the air, the type of vaccine involved, the length of time of the excursion, etc.
In general, if it can be reliably determined that the vaccine in question was not stored below 32°F and the manufacturer's stability data concurs, most immunization programs and vaccine manufacturers would not recommend wasting the vaccine or revaccinating recipients.
For an extended period, the temperature in the vaccine-storage refrigerator in our practice was too cold. We assume all the vaccines given during that period are considered invalid. How should we schedule the revaccinations?
If administered vaccine is found to be stored at an inappropriate temperature, whether too cold or too warm, the provider should contact the state health department to determine if the vaccine dose is invalid. If the vaccine dose is determined to be invalid, another dose should be given. This applies to both inactivated and live vaccines. If the damaged vaccine was a live virus vaccine (e.g., MMR, MMRV, VAR), you should wait at least 4 weeks after the previous (damaged) dose was given before repeating it. If the damaged vaccine was an inactivated vaccine, you can give the repeat dose on the same day you gave the damaged dose or at any other time. If you prefer, you can perform serologic testing to check for immunity for certain vaccinations (e.g., measles, rubella, hepatitis A, diphtheria, varicella, and tetanus).
Vaccine Viability and Expiration
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How long can reconstituted MMR vaccine be stored in a refrigerator before it must be discarded?
The amount of time in which a dose of vaccine must be used after reconstitution varies by vaccine and is usually outlined in the vaccine's package insert. MMR must be used within 8 hours of reconstitution. MMRV must be used within 30 minutes; other vaccines must be used immediately. The Immunization Action Coalition has a staff education piece that outlines the time allowed between reconstitution and use, as stated in the package inserts for a number of vaccines. This handout can be found at the following link: www.immunize.org/catg.d/p3040.pdf.
What is a temperature excursion?
Any temperature reading outside the recommended range for vaccine storage is a temperature excursion. However, it is generally the total amount of time, or cumulative time, out of range that affects the viability of vaccine. Any time appropriate vaccine storage temperatures are in question, stop giving vaccinations and contact your state immunization program and/or the vaccine manufacturer for further guidance about whether or not a vaccine may be used. The CDC Storage and Handling Toolkit contains detailed guidance on the management of a temperature excursion. See www.cdc.gov/vaccines/hcp/admin/storage/toolkit/storage-handling-toolkit.pdf, pages 12–15.
How long is a vaccine viable if it has been stored in the refrigerator in a syringe?
Disposable syringes are meant for administration of immunobiologics, not for storage. CDC recommends that vaccines that have been drawn into syringes by the provider be discarded at the end of the clinic day if unused. Manufacturer-filled syringes that have not been activated (i.e., have not had the needle guard removed or a needle attached) may be kept and used until their expiration date.
What are the CDC guidelines regarding use of multiple dose vaccine vials?
Vaccines in multidose vials (MDVs) that do not require reconstitution can be used through the expiration date printed on the label as long as the vaccine is not contaminated unless indicated otherwise by the manufacturer. For example, inactivated polio vaccine in an MDV can be used through the expiration date on the vial. For some vaccines, the manufacturer specifies that once the MDV has been entered or the rubber stopper punctured, the vaccine must be used within a certain number of days. This is commonly referred to as the "beyond-use date" (BUD). Any vaccine not used within the BUD should be discarded. Specific information regarding the BUD can be found in the product information. For example, the package insert for some inactivated influenza vaccine indicates once the stopper of the MDV has been pierced, the vial must be discarded within 28 days. Package inserts for vaccines can be found at www.immunize.org/fda.
When removing doses from a multidose vial we can sometimes get an extra dose beyond what the manufacturer says is in the vial. Can we continue to remove doses from the vial until it is empty?
No. Only the number of doses indicated in the manufacturer's package insert should be withdrawn from the vial. For some vaccines, the package insert also may indicate the maximum recommended number of punctures of the vial stopper. After the maximum number of doses has been withdrawn or the number of punctures of the stopper has met the recommended limit, the vial should be discarded, even if there is vaccine remaining in the vial and the expiration date has not been reached.
When the expiration date of a vaccine indicates a month and year, does the vaccine expire on the first or last day of the month?
Vaccine may be used through the last day of the month indicated on the expiration date. After that, do not use it. Monitor your vaccine supply carefully so that vaccines do not expire.
I'm confused about how to correctly interpret expiration dates on vaccines.
The expiration date is the date by which the vaccine should be used. Vaccines may be used up to and including this date unless otherwise stated in the manufacturer's product information. The expiration date is based on the assumption that the vaccine has been properly handled and that it has not become contaminated.
Some vaccines expire within a certain time after opening or after reconstitution. Multidose vials that contain bacteriostatic agents that prevent the growth of bacteria and may be used until the expiration date printed on the vial unless they become contaminated. Single-dose vials and manufacturer-filled syringes do not contain bacteriostatic agents. Once the cap has been removed or the sterile seal has been broken on these vaccines, they should be administered. Lyophilized (freeze-dried) vaccine must be used within a specified time frame after it has been reconstituted. You may find IAC's educational piece titled Vaccines with Diluents: How to Use Them helpful. It's available at www.immunize.org/catg.d/p3040.pdf.
What should I do with expired vaccines?
First and foremost rotate your vaccine supply so expensive vaccine does not expire in your refrigerator. If you discover expired vaccine, remove it from the refrigerator or freezer so that it is not inadvertently given to a patient. Expired vaccines and diluents should NEVER be administered, even if it is only 1 day past the expiration date. Contact your immunization program, vaccine supplier, or vaccine manufacturer for specific policies about disposing expired vaccines.
Is it acceptable to write the expiration date (the "Beyond Use Date") of an opened vaccine multidose vial on the box rather than the vial or must it be written on the vial?
It is acceptable to put the Beyond Use Date (BUD) on the packaging; this may help when reviewing inventory. But a provider should always read the label on the vial before administering a vaccine. It is possible for a vial to be placed in the wrong box. So the vial label is the safest place to put the BUD. Vial labels are small and it may require putting an extra sticky label on the vial.
What should we do if a dose of expired vaccine is given to a patient?
The dose should be repeated. If the error was detected on the same clinic day, you can repeat the dose that day. If the error is detected more than one day later and if the expired dose is a live virus vaccine, you must wait at least 28 days after the previous (expired) dose was given before repeating it. If the expired dose is not a live vaccine, the dose should be repeated as soon as possible. An exception to this is for recombinant zoster vaccine (Shingrix, GlaxoSmithKline); the repeat dose should be given 4 weeks after the invalid dose. If you prefer, you can perform serologic testing to check for immunity for certain vaccinations (e.g., measles, rubella, hepatitis A, diphtheria, varicella, and tetanus).
Some manufacturers' package inserts state that a vaccine should be used immediately after reconstitution. In the context of reconstitution and administration of vaccines, how does CDC define "immediately"?
There are various requirements for the use of vaccines after reconstitution. Some manufacturers' package inserts require that the vaccine be used or discarded in varying time frames ranging from 24 hours after reconstitution to immediately after reconstitution. While the specific timeframes are simple to interpret, there can be some confusion as to what the requirement of "immediately" actually means.
CDC considers "immediately" to be the reasonable time it takes to prepare and transport the vaccine to the patient to be administered. This would include any limited documentation that may be related to this process. It is up to the judgment of a provider to determine if a vaccine has not been used in the appropriate time. Some manufacturers have indicated to providers that "immediately" can be up to 30 minutes. The definition of "immediately" varies from manufacturer to manufacturer. Some do not have the data to put forth a general timeframe as to what "immediately" means. CDC recommends that the provider contact the manufacturer if any question arises about whether or not a vaccine dose has been used in the appropriate timeframe.
Where can I get the most up-to-date information about vaccine storage and handling?
CDC publishes and routinely updates a comprehensive Vaccine Storage and Handling Toolkit covering topics such as vaccine storage units, temperature monitoring devices, and inventory management, vaccine transport and emergency vaccine storage and handling. The toolkit also contains troubleshooting guides to assist with vaccine storage unit issues or temperature excursions. This terrific resource is available online at www.cdc.gov/vaccines/hcp/admin/storage/toolkit/storage-handling-toolkit.pdf.
In addition, IAC maintains many free, downloadable materials at www.immunize.org/handouts/vaccine-storage-handling.asp.
Our clinic needs to buy new equipment to be in compliance with these updated recommendations. How do we know what are the best products to purchase?
The CDC Storage and Handling Toolkit, available at www.cdc.gov/vaccines/hcp/admin/storage/toolkit/storage-handling-toolkit.pdf, contains information about recommended features to look for when selecting a temperature monitoring device or storage unit. If you store Vaccines for Children (VFC) or other federally-purchased vaccines, you may contact your state immunization manager or Vaccines for Children (VFC) coordinator for additional information on their recommendations or requirements. Contact information can be found here: www.immunize.org/coordinators.
