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Digital Data Logging Is Essential for Temperature Monitoring for Vaccines

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A female clinician stands inside the open door of a vaccine storage unit equipped with a data logger.

Key Takeaways:

–   The CDC has required digital data loggers since 2018 for all VFC providers
–   The CDC also recommends using a digital data logger on every vaccine storage unit, no matter what the vaccine
–   Precise temperatures are required for the viability of the COVID-19 vaccine; the Pfizer vaccines in particular require ultra-cold temperatures prior to thawing
–   Only a digital data logger can assure that vaccines are kept at the required temperatures with unparalleled accuracy
–   Logs can be downloaded for analysis and digitally stored to meet CDC recording and reporting requirements

The COVID-19 vaccines highlighted the need for accurate and precise storage monitoring

Accurate and complete records of the history of vaccine temperatures are vital to preserving both the efficacy and safety of these drugs. Yet some vaccine providers fail to use a continuous temperature monitoring system in their refrigerators and freezers. A digital data logger (DDL) provides the most accurate data on the temperature of vaccines.

In fact, in their Vaccine Storage and Handling Toolkit, the Centers for Disease Control and Prevention (CDC) recommends using a digital data logger as the temperature monitoring device on every vaccine storage unit. This technology offers detailed information on every temperature recording at the preset intervals. This is far superior to a minimum/maximum thermometer, which is designed to show the coldest and warmest temperatures the unit has reached.

Temperature monitoring for vaccines is essential, and the more accurate, the better. DDLs use a buffered temperature probe that is more accurate than standard thermometers that measure air temperature. The data gathered by a DDL can be downloaded to a computer for review, removing the need for human-recorded temperatures and associated errors. Inaccurate temperature recording can lead to unnecessary disposal of vaccines or administration of compromised vaccines. A vaccine-specific data logger not only eliminates these problems but also keeps you in compliance with CDC guidelines. 

Maintaining vaccine temperatures requires data logging

In the days before digital data loggers, vaccine temperature was monitored by humans having to check the temperature on a pre-set schedule. If someone forgot to check, that was data lost, and whether the vaccine was kept at the proper temperature can’t be ascertained. And if the doors were left open, you face vaccine spoilage.

Temperature monitoring for vaccines today requires investment in a reliable DDL. These digital data loggers:

  • Provide detailed information on temperatures at preset intervals, something standard thermometers can’t do
  • Perform logging 24 hours a day, even when staff members are not present
  • Offer an accurate log of temperature data on a continuous basis
  • Display a visual alarm
  • Provide a continuous, active log of temperature data and alarming to demonstrate CDC compliance

The data logger you choose should have a local visual display of both the current and maximum and minimum temperatures and programmable logging intervals of a maximum of every 30 minutes. It also should be able to provide daily audits of correct temperature along with a calibration testing certificate.

The CDC requires digital temperature monitoring for vaccines for VFC providers

The CDC mandated DDLs in 2018 for providers in the Vaccine for Children (VFC) program. This is a publicly funded vaccine program at no cost for eligible children. These data loggers must meet all CDC  requirements, which include:

  • A temperature probe
  • An active temperature display that can be read from the exterior of the unit
  • The ability to continuously monitor temperatures
  • Provide record when data is routine downloaded

In addition, they recommend these additional DDL features:

  • An alarm for when temperatures are out of range
  • An indicator for the current, minimum, and maximum temperatures
  • A low-battery indicator
  • Accuracy of +/–0.5° C (+/–1° F)
  • Enough storage for at least 4,000 readings 
  • A detachable probe in a thermal buffered material

Continuous, monitored temperature control of vaccines is essential, and nothing illustrated this better than issues with the COVID-19 vaccines. These vaccines require temperatures far lower than most, and those without DDLs found it extremely hard to manage. By September 2021, more than 15 million doses of the vaccines had been thrown away just since March of the same year. 

The critical role of DDLs in COVID-19 vaccines

Temperature monitoring for vaccines is essential, no matter what disease they treat. But for COVID-19, ultra-cold storage is required, and temperature ranges are different before use and after it is opened. The storage requirements are strict:

  • The Pfizer vaccines, before thawing, must be stored in an ultra-cold freezer. The temperature range is –80° Celsius (C) to 60°C. That’s between –112° and –76° Fahrenheit. Once thawed, it can be stored in a refrigerator for up to five days at temps between 2°C and 25°C. Once the vial is first used, it can be stored at that same temperature for a maximum of six hours.
  • The Moderna vaccine requires storage prior to puncturing the vial at recommended temperatures between –25°C and –15°C or refrigerated for up to 30 days at –2°C and –8°C. It also can be unrefrigerated if used within 12 hours.  After first use, it must be stored between 2°C and 25°C for no longer than six hours. 
  • The Johnson & Johnson (Janssen) vaccine has less stringent requirements but must be refrigerated between 2°C and 8°C for no longer than three months when unopened or stored unrefrigerated at between 9°C and 25°C for no more than 12 hours. After first use, the same refrigeration temperatures are required, or it can be left at room temperature for two hours maximum.

Vaccine storage equipment requires monitoring to quickly identify temperature variations and excursions so fast action can be taken to correct them, preventing the loss of vaccines for patients who need them. 

Data logging provides higher efficiency and accuracy. While it can be performed by humans, it’s time-consuming, and there’s always the potential for human error. A data logger means that measurements are taken automatically and precisely at preset intervals that don’t require human intervention unless an alarm is indicated. 

Digital data loggers offer the means to download logs and perform a detailed analysis of just how well your vaccine storage units are operating. Logs can also be kept – electronically – for the three years mandated by the CDC or even longer if required by state regulations. 

Marathon Products: For Reliable, Efficient Vaccine Storage Data Logging

Marathon Products is a leading manufacturer and distributor of precision environmental monitoring devices for temperature, humidity, and vibration for the life sciences and semiconductor industries. Our sensors are highly reliable and can be used for low-temperature or high-temperature applications.

All of our devices are 100% tested to ensure reliability, are FDA 21cfr compliant, and we have a no-questions-asked return policy. We have monitoring devices for every cold supply chain need at competitive prices, so don’t ship without us! For more information, email us at or call us at 800-858-6872.

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