2°C and 8°C are the official limits that a vaccine must be stored between.
Of the two temperatures, the lower one is the more critical. At 0°C certain vaccines freeze and become useless. This is important to keep in mind when dealing with the issue.
The higher temperature is less rigid because warm vaccines age faster, they don’t suddenly become ineffective. It’s similar to leaving milk out and having it go off faster. If it is kept refrigerated it will last weeks but leave it out in summer and it won’t last a couple of hours.
Losing power to a vaccine fridge obviously means you are losing the ability for the fridge to cool down. The speed at which it heats up is determined by a number of factors:
If you know that you are going to have a power outage in advance then there are a couple of simple things you can do:
Once the power fails there are a couple of things that you can try to do to minimise the temperature change:
A couple of the tips involve the use of ice. This poses a more significant risk if done incorrectly.
Vaccines must NOT come in direct contact with the ice.
The temperature can not drop below 0°. Using an eski filled with ice is the most likely cause, but packing a fridge with ice will also potentially cause freezing.
There are ways of avoiding direct contact with ice such as using cardboard or material to act as a barrier. Don’t use too much or it will insulate the ice.
Check the maximum temperature of the fridge and if possible record how long it has been since the power failed.
A better solution is to have used a temperature logger which will provide not only the maximum temperature, but a detailed history as to when it exceeded 8°, for how long, and how warm the fridge actually became. This information is then better used to determine if the vaccines have been compromised. OnSolution can provide advice on the best temperature logger for your needs.
You may need to notify the authority to determine if the vaccine is still viable, or if it needs to be disposed of. If in doubt, do not use the vaccines until this check has been completed.
Latency, when it comes to temperature logging, refers to the delay between a change in temperature and when that change is detected and recorded by the logger. This delay can be due to the sensor’s design, the materials it’s placed in, or the logging interval. While it might sound like a disadvantage, latency can actually serve a useful purpose in certain environments—particularly where short-term temperature spikes are common but not harmful.
For example, in a busy commercial fridge, the temperature may briefly rise every time the door is opened. A logger with high latency won’t immediately react to these short fluctuations, helping to avoid unnecessary alarms or false data indicating a problem when there isn’t one. In these cases, a slight delay in response acts like a filter, focusing attention on real issues—such as prolonged exposure to unsafe temperatures—while ignoring the everyday ups and downs that don’t affect product quality or safety.
Depending on the type of logger you have, connecting your logger to your PC means either:
First Generation LogTags use a separate Reader (sometimes called a dock) for configuration and for downloading recorded data.
The Second Generation loggers only require a USB port or cable. Apart from saving the cost of the Reader, this makes them much better suited for shipping, because the recipient doesn’t need a LogTag Reader to download a report about the shipment’s journey.
