Vaccine storage and handling

For frequently asked questions and more information, click here.

*Please refer to the full online version of the CDC Vaccine Storage & Handling Toolkit for more information and to verify you have the most current information.

Recommendations from:
U.S. Department of Health and Human Services
Center for Disease Control and Prevention (June 2016)

Excerpts for Animal Hospitals

  1. Refrigerated vaccines should be stored at temperatures between 2° C and 8° C (36° F and 46° F). The thermostat should be set at midrange to achieve a temperature of about 5° C (40° F), which will decrease the likelihood of temperature excursions.
  2. For specific, detailed storage and handling protocols for individual vaccines always refer to the manufacturers’ product information and package inserts, or contact the manufacturer directly.
  3. While exposure to any inappropriate conditions can affect potency of refrigerated vaccines, a single exposure to freezing temperatures (0° C [32° F] or colder) will destroy some. Liquid vaccines that contain an aluminum adjuvant can permanently lose potency when exposed to freezing temperatures.
  4. Vaccine appearance is not a reliable indicator that vaccines have been stored in appropriate conditions. For example, inactivated vaccines, even when exposed to freezing temperatures, may not appear frozen, giving no indication of reduced or lost potency.

Staff training

All staff members who receive deliveries and/or handle or administer vaccines should be familiar with storage and handling policies and procedures at your facility. Keep standard operating procedures (SOPs) for storage and handling near storage units and make sure staff knows where to find them.

CDC recommends that storage and handling training should be done:

  • As part of new employee orientation
  • Annually as a refresher for all staff involved in immunization activities
  • Whenever new vaccines are added to inventory
  • Whenever recommendations are updated

CDC offers an online training module, “You Call the Shots: Vaccine Storage and Handling”

Vaccine coordinator

Designate a person to be the primary vaccine coordinator for your facility. This person will be responsible for ensuring all vaccines are stored and handled correctly. Appoint a second staff member to serve as an alternate in the absence of the primary coordinator (this is particularly important in case of after-hour emergencies). Both coordinators should be fully trained in routine and emergency policies and procedures.

Coordinator responsibilities include:

  • Ordering vaccines
  • Overseeing proper receipt and storage of vaccine deliveries
  • Documenting vaccine inventory information
  • Organizing vaccines within storage units
  • Setting up temperature monitoring devices
  • Reading and recording storage unit temperatures a minimum of two times each workday
  • Reading and recording minimum/maximum temperatures from a digital data logger one time each workday, preferably each morning
  • Reviewing and analyzing temperature data at least weekly for any shifts in temperature trends
  • Rotating stock at least weekly so vaccines with the earliest expiration dates are used first
  • Removing expired vaccine from storage units
  • Responding to out-of-range temperatures (temperature excursion)
  • Maintaining all documentation, such as inventory and temperature logs
  • Ensuring staff is properly trained
  • Monitoring operation of storage equipment and systems
  • Overseeing proper vaccine transport (when necessary)
    • Overseeing emergency preparations
    • Ensuring appropriate handling of vaccines during a disaster or power outage

Refrigerator storage units

Refrigerators typically used for vaccine storage are available in different grades (household and purpose-built) and types (stand-alone and combination refrigerator/freezer). Purpose-built units are sometimes referred to as “pharmaceutical grade” and are designed specifically for storage of biologics.

These units often have:

  • Microprocessor-based temperature control with a digital temperature sensor (thermocouple, resistance temperature detector, or thermistor)
  • Fan-forced air circulation with powerful fans or multiple cool air vents inside the unit that promote uniform temperature and fast temperature recovery

CDC makes the following recommendations for vaccine storage units:

Use purpose-built units designed to either refrigerate or freeze (can be compact, under-the counter-style or large units).

If a purpose-built unit is not available, use a stand-alone household unit.

Do not store any vaccine in a dormitory-style or bar-style combined refrigerator/freezer unit under any circumstances. These units have a single exterior door and an evaporator plate/cooling coil, usually located in an icemaker/freezer compartment. These units have been shown to pose a significant risk of freezing vaccines, even when used for temporary storage. (Note: Not all small storage units are dormitory- or bar-style units. Compact purpose-built units for biologics can be used to store vaccines.)

Make sure the storage unit has enough space to store the largest inventory you might have at the busiest point in the year without crowding.

Remove any deli, fruit, and vegetable drawers from refrigerator units. This provides extra space for water bottles to help maintain stable temperatures and prevents use of the drawers for storing food, beverages, or vaccines.

Use safeguards to ensure the doors of the unit remain closed (for example, self-closing door hinges, door alarms, door locks, etc.).

Temperature monitoring equipment (digital data loggers)

An accurate temperature history that reflects actual vaccine temperatures is critical for protecting your vaccines. Every vaccine storage unit must have a temperature monitoring device, and investing in reliable devices is less expensive than replacing vaccines wasted due to inaccurate temperature readings.

CDC recommends the use of a continuous monitoring and recording digital data logger (DDL) with a current and valid Certificate of Calibration Testing (also known as a Report of Calibration), set at a minimum recording interval of at least every 30 min. Unlike a simple minimum/maximum thermometer, which only shows the warmest and coldest temperatures reached in a unit, continuous monitoring and recording DDLs provide detailed information on all temperatures recorded at preset intervals. 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 instead to reflect air temperature. DDLs provide the most accurate storage unit temperature information, including details on how long a unit has been operating outside the recommended temperature range (referred to as a temperature excursion).

CDC recommends DDLs with the following characteristics:

  • Detachable probe in a thermal buffered material (e.g., glycol, glass beads, sand, Teflon®)
  • Alarm for out-of-range temperatures
  • Low-battery indicator‡
  • Current, minimum, and maximum temperature indicator
  • Recommended uncertainty of +/-0.5° C (+/-1° F)
  • Logging interval (or reading rate) that can be programmed by the user

Temperature data from a DDL can 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 is critical for vaccine safety, so it is important to decide whether independent software or a website program will work best for your facility.

CDC recommends that a DDL’s current and valid Certificate of Calibration Testing (Report of Calibration) should include:

  • Model/device name or number
  • Serial number
  • Date of calibration (report or issue date)
  • Confirmation that the instrument passed testing (or instrument in tolerance)
  • Recommended uncertainty of +/-0.5° C (+/-1° F) or less

Certain types of temperature monitoring devices have significant limitations and should not be used to measure temperatures in a vaccine storage unit. These devices can be difficult to read and, because they only show the temperature at the exact time they are read, may fail to detect temperatures outside the recommended range.

Specifically, CDC does not recommend the following temperature monitoring devices:

  • Alcohol or mercury thermometers, even if placed in a fluid-filled biosafe liquid vial
  • Bi-metal stem temperature monitoring devices
  • Food temperature monitoring devices
  • Chart recorders
  • Infrared temperature monitoring devices
  • Temperature monitoring devices that do not have a current and valid Certificate of Calibration Testing

Devices sold in hardware and appliance stores are generally designed to monitor temperatures for household food storage. They are neither calibrated nor accurate enough to ensure vaccines are stored within the correct temperature range.

Best practices for storing vaccine and diluent in a refrigerated unit include:

  • Always store vaccines in their original packaging with lids closed until ready for administration. This protects them from light and provides additional thermal protection/stability. Never store loose vials outside of their packaging. This increases the risk of administration errors, exposes vaccine to light, and makes it more difficult to track expiration dates and manage inventory.
  • Place water bottles on the top shelf, floor, and in the door racks. Putting water bottles in the unit can help maintain stable temperatures caused by frequently opening and closing unit doors or a power failure. It can also prevent vaccines from being stored in areas where there is a greater risk of out-of-range temperatures (such as the top shelf, floor, and door). Place water bottles carefully so they cannot dislodge, preventing the door from closing securely or weighing the door down so the seals are not tight. Label all water bottles “DO NOT DRINK.”
  • Whenever possible, store diluent with the corresponding refrigerated vaccine.
  • To maintain proper temperatures in the refrigerator, leave the freezer on at the factory-set or midpoint temperature setting.
  • It may take 2 to 7 days to stabilize the temperature in a newly installed or repaired refrigerator. Before using a unit to store vaccines, check and record temperatures a minimum of two times each workday for 2 to 7 days.
  • Attach labels to shelves and containers to clearly identify where each type of vaccine and diluent is stored.
  • Store vaccines and diluents with similar packaging or names on different shelves to minimize the risk of administration errors.
  • Place vaccines and diluents in the center of the unit 2 to 3 inches away from walls, ceiling, floor, and door.
  • 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 (2° C to 5° C colder) or in shelves on the door. The instability of temperatures and air flow in these areas may expose them to inappropriate storage temperatures.
  • Do not store vaccines in deli, fruit, or vegetable drawers or in the door. Temperatures in these areas are not stable and can differ from those inside the main part of the unit.
  • Arrange vaccines and diluents in rows, allowing space between rows to promote air circulation. This helps each vaccine and diluent maintain a consistent temperature.
  • Place vaccines and diluents with the earliest expiration dates in front of those with later expiration dates.
  • Do not pack a storage unit too tightly. This can restrict air circulation and impact vaccine temperature.
  • If possible, no items other than vaccines, diluents, and water bottles should be placed or stored in the units.
  • Food and beverages should never be stored in the unit with vaccines. Doing so can lead to frequent opening of the door to access food, putting vaccines at risk of temperature fluctuations and excessive light exposure. It can also result in spills and contamination.
  • If other medications must be stored in the same unit as vaccines, never store these products in the same container with vaccines. Always store them below vaccines and on a different shelf. This prevents
  • contamination and reduces the likelihood of medication errors.
  • Check unit doors throughout the day and always at the end of the day to ensure they are tightly closed. A door left open not only affects temperature in the unit, but can also expose vaccines to light, putting them at risk of reduced potency.

Temperature monitoring device

Place the buffered probe of the digital data logger (DDL) in the center of the unit with the vaccines surrounding it. A device placed near the walls, floor, vent, ceiling, or door may indicate temperatures that are colder or warmer than the actual vaccine temperature.

Place the DDL’s active digital display outside the unit so temperatures can be read without opening the door and disturbing the probe.

DDL should be set to measure temperatures at least every 30 min.

CDC recommends on a twice daily basis:

Check and record storage unit temperature readings each workday—in the morning when you arrive and in the evening before leaving. This should be done even if there is a temperature alarm or a DDL temperature monitoring device.

A temperature monitoring log sheet should be placed on each storage unit door (or nearby), and the following information should be recorded:

  • Temperature
  • Date
  • Time
  • Initials of person recording the data

CDC recommends on a weekly basis:

  • Review storage unit temperature readings and review continuous DDL software or website information for changes in temperature trends that might require action (adjusting unit temperature or repairing/replacing storage or temperature monitoring equipment).
  • File this information so it can be analyzed for long-term trends and/or recurring problems. Temperature data should be kept for 3 yr.

Temperature monitoring device maintenance

Because all temperature monitoring devices experience “drift” over time that affects their accuracy, calibration testing should be done every 1 to 2 yr or according to the manufacturer’s suggested timeline.

If calibration testing indicates your temperature monitoring device is no longer accurate within ±.5° C (±1° F), it should be replaced. Adjustments to correct accuracy of the device are not recommended. You may prefer to replace the device rather than submitting it for calibration testing. Any new temperature data logger must have a current and valid Certificate of Calibration Testing (also known as Report of Calibration).

Out-of-range Temperatures

Out-of-range storage temperatures or inappropriate conditions for any vaccine require immediate action. Any temperature reading outside ranges recommended in the manufacturers’ package inserts is considered a temperature excursion. In general, manufacturers analyze information about the magnitude of the temperature excursion and the total amount of time that temperatures were out of range, as well as information about the vaccine in question, to determine whether a vaccine is likely to be viable.

If there is any question about whether vaccines may have been exposed to a temperature excursion because the unit became too cold or too hot, CDC recommends the following steps:

  1. Any staff member who hears an alarm or notices a temperature excursion on the DDL should notify the primary or alternate vaccine coordinator immediately or report the problem to their supervisor.
  2. Label exposed vaccines “DO NOT USE,” and place them in a separate container apart from other vaccines in the storage unit (do not discard these vaccines).
  3. The vaccine coordinator, supervisor, or, if necessary, the person reporting the problem should begin to document the event:
    1. Date and time of the temperature excursion
    2. Storage unit temperature and room temperature, if available (including minimum/maximum temperatures during the time of the event, if available)
    3. Name of the person completing the report
    4. Description of the event: General description (i.e., what happened). If using a DDL, determine the length of time vaccine may have been affected.
    5. Inventory of affected vaccines.
    6. List items in the unit (including water bottles) other than vaccines.
    7. Any problems with the storage unit and/or affected vaccines before the event
    8. Other relevant information
  4. Contact your vaccine manufacturer(s) for further guidance on whether to use affected vaccines and for information about whether patients will need to be recalled for revaccination. Be prepared to provide documentation of the event (e.g., temperature log data) to ensure you receive the best guidance.
  5. Adjust unit temperature to the appropriate range. At a minimum, check the temperature monitoring device to make sure it is appropriately placed in the center of the vaccines.
  6. Complete your documentation of the event, including:
    1. Action taken
      1. What you did with vaccine and the time
      2. Whom you have contacted and instructions received
      3. What you have done to prevent a similar future event
    2. Results
      1. What happened to affected vaccines
      2. Other comments

Adjusting storage unit temperatures

Storage unit temperatures will likely need to be adjusted over time. In some situations, thermostats may need to be reset in summer and winter, depending on room temperature.

Remember that temperatures within any storage unit will vary at least slightly, even with normal use. Therefore, before making any adjustment:

  • Confirm the unit is securely plugged into a power source.
  • Check the temperature inside the storage unit.
  • Wait 30 min, without opening the door, to allow the temperature to stabilize, and check
  • it again to verify the thermostat should be adjusted. If you believe there could be an issue with your monitoring device, use your backup device to confirm the temperature. If you confirm that an adjustment is needed:
  • Refer to the owner’s manual for detailed instructions.
  • Turn the thermostat knob slowly to avoid going outside the correct temperature range, and make a small adjustment toward a warmer or colder setting as necessary.
  • Allow the temperature inside the unit to stabilize for 30 min without opening the door.
  • Recheck the temperature.
  • Repeat these steps as needed until the temperature has stabilized at around 5° C (40° F) for a refrigerator or between -50° C and -15° C (-58° F and +5° F) for a freezer.
  • Consider placing additional water bottles in the unit to help improve temperature stability. If you are using a combination storage unit, please note that adjustments to the freezer temperature can adversely affect the refrigerator compartment temperature, possibly resulting in frozen refrigerated vaccines.

Vaccine deliveries

Scheduling and receiving deliveries

All staff members who might receive vaccine deliveries must be aware of the importance of maintaining the cold chain. They should be trained to immediately notify the vaccine coordinator or alternate when deliveries arrive so that vaccines are checked in and stored quickly.

The person arranging for deliveries should know which staff member will be available to receive them, considering holidays, vacations, and any changes in the facility’s hours of operation. Ideally, the vaccine coordinator or alternate should be available to receive deliveries.

Never leave a vaccine shipping container unpacked and unattended. If vaccines and diluents inside get too warm, they cannot be used. Be sure all staff members know that vaccine deliveries require immediate attention.

Unpacking Deliveries

Vaccines and diluents must be carefully unpacked, stored at recommended temperatures, and documented immediately after they arrive. Do not place an unopened and/or unpacked shipment box in a vaccine storage unit.

When unpacking deliveries:
Examine the shipping container and vaccines for signs of physical damage.
Check the contents against the packing list to be sure they match.

If the shipment includes lyophilized (freeze-dried) vaccines, make sure they came with the correct type and quantity of diluents.

Check both vaccine and diluent expiration dates to ensure you have not received any expired or soon-to-expire products.

Vaccine inventory accounting

Expiration dates

Understanding expiration dates is a key component of managing your vaccine inventory. Vaccine and diluent expiration dates indicate when the product must be discarded if it has not been used. These dates are printed on vials, manufacturer-filled syringes, and packages.

When the expiration date has only a month and year, the product may be used up to and including the last day of that month. If a day is included with the month and year, the product may only be used through the end of that day.

Stock rotation and removal

The vaccine coordinator (or other designated person) should rotate vaccine and diluent stock at least once a week, as well as each time your facility receives a vaccine delivery. Arrange stock in the storage unit so that for each vaccine type, doses with the earliest expiration dates are placed in front of those with later expiration dates.

Check expiration dates on vaccines and diluents at least once a week, and immediately remove any expired vaccines and diluents to avoid inadvertently administering them.

Preparing vaccine for administration

Vaccine preparation is the final step in the cold chain before administration. Handling vaccines with care is equally as important as storing them properly.

  • Vaccines should be prepared in a designated area away from any space where potentially contaminated items are placed.
  • Only prepare vaccines when you are ready to administer them. Always check expiration dates and confirm that you have selected the correct vaccine.
  • Only administer vaccines you have prepared. This is a quality control and patient safety issue and a best practice standard of medication administration. If vaccine is drawn up by one person but administered by another, the person administering the vaccine cannot be sure what is in the syringe and whether it is safe.

A single-dose vial (SDV) contains ONE dose and should be used ONE time for ONE patient.

  • Do not combine leftover vaccine from one SDV with another to obtain a dose.
  • Do not open an SDV until ready to use. Before you remove the protective cap, always check the vial to make sure you have the correct vaccine. Once you remove the cap, you must use the vaccine because it may not be possible to determine if the rubber seal has been punctured.
  • Discard any unused SDVs without a protective cap at the end of the workday.


Lyophilized (freeze-dried) vaccines may be in the form of a powder or pellet that must be mixed with a liquid (diluent) in a process known as “reconstitution” before being administered.

Liquid diluents vary in volume and composition and are specifically designed to meet volume, pH (acid/alkaline balance), and chemical requirements of their corresponding vaccine. Some diluents contain antigen.

Diluents are not interchangeable unless specified by the manufacturer. Even if the diluent is composed of sterile water or saline, use only the diluent supplied with the vaccine to reconstitute it. Never use a stock vial of sterile water or normal saline to reconstitute vaccines.

Predrawing vaccines

CDC recommends drawing up vaccines only at the time of administration. Once vaccines are inside syringes, it is difficult to tell them apart, which can lead to administration errors. Predrawing can also result in vaccine waste if more is drawn up than is needed.

General-use syringes are designed for immediate administration—not for storage. Contamination and growth of microorganisms can occur in syringes with predrawn vaccine that does not contain a preservative. In addition, vaccine components may interact with polymers in a plastic syringe over time, potentially reducing vaccine potency.

*Please refer to the full online version of the CDC Vaccine Storage & Handling Toolkit for more information and to verify you have the most current information.

These guidelines are supported by a generous educational grant from
Boehringer Ingelheim USA Inc., Merck Animal Health, and Zoetis.