For the transport and storage of vaccines. 2°C to 8°C are the critical temperatures. In fact, vaccines are still viable below 2°C but once some vaccines freeze they are no longer viable. So 0°C is actually the super critical vaccine temperature and 2°C provides a buffer zone to take into account inaccuracies and other sources of variations.
Higher temperatures will shorten the shelf life of a vaccine. It is similar to storing milk – the warmer it is, the shorter the time it will last. The “Strive for 5”C” campaign is focused on providing an optimum temperature to aim for. It moves the focus away from the negative and to an ideal.
If you want more information, you may be interested in our new website on Vaccine Temperature and Vaccine storage.