Top 5 Vaccine Temperature Logging Devices

May 19, 2024

Why Vaccine Temperature Logging is Important

Continuous monitoring of vaccine storage temperature with a temperature monitoring device is critical to ensuring vaccination efficacy. Exposure to inappropriate storage temperatures can degrade vaccine potency, putting both products and patients at risk. 

Vaccines licensed for refrigerator storage often need to be kept in temperature ranges of just 2°C to 8°C. [1] With such a narrow range, it is simply too easy for temperature excursions to go undetected without the use of a continuous temperature logging system. Because cumulative exposure to out-of-range temperatures degrades vaccine potency over time, a few degrees can make all the difference to the shelf life of stored vaccines.

This is why continuous temperature monitoring is so important, and why since 2012, the CDC has recommended the use of digital temperature data loggers for recording vaccine storage temperatures. This recommendation became a requirement for Vaccines for Children (VFC) program participants in 2018. Additionally, the CDC’s Vaccine Storage and Handling Toolkit [2] outlines minimum specifications and requirements for data loggers used in vaccine temperature monitoring.

What is a Digital Data Logger?

Digital Data Loggers (DDLs)—also known as Temperature Monitoring Devices (TMDs)—are electronic devices that automatically and continuously monitor and record changes in temperature. Digital data loggers typically use an external probe which measures refrigerator or freezer temperatures, and a base unit which either stores and/or transmits the data.

Temperature monitoring devices can be single, standalone units or be made up of multiple, discreet components. 

Most digital data loggers intended for use in primary care settings utilize a buffered temperature probe—the most accurate way of measuring the temperatures actually being experienced by vaccines—since air temperature is not a good reflection of the temperatures of the vials/pre-filled syringes themselves.

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VFC Requirements for Digital Data Loggers

Providers enrolled in the Vaccines for Children (VFC) program are required to use a temperature monitoring device [3] for each vaccine storage refrigerator and/or freezer.

Data from these temperature monitoring devices should be kept on hand for at least as long as state regulations require, with recommendations for a minimum record length coming in at 3 years. An additional benefit of these requirements is the data analysis they enable, which can easily uncover potential issues with your storage unit(s).

Temperature Monitoring Devices must also meet the following VFC requirements:
Digital data loggers must be accurate in their readings +/-1.0°F (+/-0.5°C), must be capable of taking readings at least once every 30 minutes, must store at least 4000 readings, must utilize a buffered temperature probe of solid material (aluminum or Teflon), liquid up to 60 mL (ethanol, glycol, or glycerin), or loose media (glass, sand, or glass bead), must have an external display, must have a clear low-battery indicator, and finally, should also have an audible or visual alarm for out-of-range temperatures.

Calibration Testing
Providers enrolled in the VFC program are required to use a VFC-compliant data logger in any freezer or refrigerator they use to store VFC vaccines. They must also have a backup available in case the primary device fails or must be sent for repair or recalibration. 

Because digital data loggers can experience a loss in accuracy over time, it is recommended that calibration testing be performed regularly according to the manufacturer of your temperature monitoring device.

All VFC data loggers must have a current certificate of calibration and should be recalibrated 3 months before their calibration is set to expire.

Features to Look for in a Digital Data Logger

No matter which temperature monitoring device you end up selecting, make sure your digital data logger has the following features at a minimum:

  • A display that indicates the current temperature as well as min/max temperatures
  • The display should be visible from the outside of the vaccine refrigerator/freezer
  • The data logger should be able to produce a downloadable set of temperature records (minimum interval of 30 minutes)
  • The accuracy of the data logger should be within at least +/- 1-degree Fahrenheit
  • A buffered temperature probe
  • An out-of-range temperature alarm
  • A low-battery signal (if applicable)

Note: changing the battery may affect accuracy—after swapping in fresh batteries, you should check the device against another data logger which you know to be accurate.

Our Top Picks for Vaccine Temperature Logging

The Onset InTemp CX402-VFC digital data logger.

Onset InTemp CX402-VFC


The InTemp CX402-VFC data logger monitors temperatures in refrigerators and freezers where vaccines are stored. It communicates wirelessly via Bluetooth Low Energy to mobile devices. The loggers are set up and data is viewed using the InTemp app where you can easily view data, check the logger status, set alarms, and create and share secure PDF reports for maintaining regulatory compliance. The logger features a display to view the current temperature, the daily high/low, visual alarms (with audible components), and the ambient temperature. 

Additionally, the CX402-VFC series of loggers are unique in that they offer different-sized glycol buffer bottles allowing you to use a buffer that best mimics the size of the vaccine vials you are monitoring.

The LogTag TRED30 digital data logger.

LogTag TRED30


The VAC-TRED30 vaccine temperature monitor is capable of covering everything needed to comply with CDC recommendations for safe vaccine storage and handling. Each logger comes calibrated for use in both refrigerator and freezer applications and can serve as either a primary or backup device. 

The logger is set up and configured with the free-to-download LogTag Analyzer 3 software. The software offers advanced options such as automation (e.g. when the logger is inserted into its docking station it downloads the data, emails it as a PDF, and reconfigures the logger for its next deployment). This is just one example of the many advanced features.

Also available is the LogTag CP110 Smart Probe which allows you to swap out pre-calibrated probes without having to send the logger back for re-calibration.

The MadgeTech VTMS digital data logger.

MadgeTech VTMS


The VTMS is a wireless temperature data logging system specifically designed to continuously monitor temperature-sensitive vaccines in refrigerators, freezers and coolers. 

This device features an LCD screen for instant access to current readings, minimum, maximum and average statistics. Equipped with user-programmable alarms, the VTMS will alert or notify users via email or text when thresholds are breached, allowing users to take immediate action. 

The VTMS is compatible with the latest MadgeTech 4 software and also comes ready for MadgeTech Cloud Services for the ability to monitor data remotely on any smartphone or internet-connected device.

The Lascar EasyLog EL-WiFi-VACX digital data logger.

Lascar EasyLog EL-WiFi-VACX


The Lascar EasyLog is a Wi-Fi-enabled digital data logger designed specifically for vaccine monitoring in refrigerators and freezers. Its bright LED and audible alarm ensure no temperature excursions go unnoticed. Additionally, it connects to your PC, mobile device, or the EasyLog Cloud wirelessly via your existing Wi-Fi network. When used with the optional EasyLog Cloud service you can set it to send email alerts in the event of an alarm.

The Berlinger FridgeTag 2L digital data logger.

Berlinger FridgeTag 2L Vaccine Monitor


The Berlinger Fridge-Tag2L is a simple digital data logger built specifically for monitoring stored vaccines in a refrigerator (a freezer version is also available). The Fridge-Tag2L doesn’t require any software, with all setup handled by two face buttons. When connected to a computer using the integrated USB plug the logger automatically creates a PDF data report showing up to 56 days of temperature data. 

You can also view up to 30 days of highs, lows, and any alarms as well as their duration on the device itself. In addition to a visual indicator, the unit also has an audible alarm. The Fridge-Tag2L uses a flat ribbon sensor cable that minimizes air gaps. This logger uses a non-replaceable battery with a typical battery life of 3 years.


[1] (2024, May 20). Storage and Handling of Immunobiologics (CDC). https://www.cdc.gov/vaccines/hcp/acip-recs/general-recs/storage.html
[2] (2024, May 20). Vaccine Storage and Handling Toolkit (CDC). https://www.cdc.gov/vaccines/hcp/admin/storage/toolkit/index.html
[3] (2024, May 20). Vaccine Storage and Handling (CDC). https://www.cdc.gov/vaccines/pubs/pinkbook/vac-storage.html
[4] (2024, May 20). Vaccine Storage and Handling Resources (CDC). https://www.cdc.gov/vaccines/hcp/admin/storage/index.html

Additional Resources
For more information on vaccine management and healthcare compliance, including best practices, training opportunities, and relevant updates on immunization programs, we recommend:

World Health Organization (WHO): https://www.who.int/immunization/diseases/en/
Centers for Disease Control and Prevention (CDC): https://www.cdc.gov/vaccines/
Immunize.org: https://www.immunize.org/

May 19, 2024