We had previously written about the cold chain for fresh flowers taking them from harvest to market.
This PDF looks at the vaccine cold chain. The operating temperature range is 2 deg C to 8 deg C. So we are not really looking at sub zero numbers. Just lightly chilled.
This quote introduces the general requirements. It is worth noting the importance of controlling exposure to strong light as well as to temperatures outside the recommended ranges:
Manufacturers recommend that temperatures must be kept below 8°C whenever vaccines are
transported between storage sites and clinics. All vaccines are sensitive to some extent to
heat and cold. Although most vaccines may be less sensitive to heat their potency and
effectiveness cannot be guaranteed unless they have been stored between +2o
C and +8o
Freezing may cause increased reactogenicity and loss of potency rendering the vaccine
useless. It can also cause hairline cracks in the container, leading to contamination of the
contents. Do not freeze.
Vaccines are also very sensitive to strong light, and exposure to ultraviolet light will cause loss
of potency, so they must always be protected against light.
The vaccine cold chain in a diagram
One of the key elements of the vaccine cold chain is the monitoring of temperature changes and a digital thermometer set up like this is one solution