Why Monitor vaccines temperature?
The World Health Organisation (WHO) recommendations on the
storage of vaccines and maintenance of the 'cold chain', stipulate
that vaccines should be transported and stored according to the
manufacturers' recommended temperature range of +2 to +8°C until
the point of administration. Heat speeds up the decline in potency
of most vaccines and freezing may cause increased reactogenicity
and loss of potency. Pharmaceutical distributors and manufacturers
will not accept any vaccine for return once it has left their
control, so vaccines may be wasted.
Failure to monitor and record temperatures accurately can mean
that health professionals may be unaware of these potential effects
on the vaccines, and of course their recipients. Problems can
arise, for example, due to a faulty fridge, the door having been
left ajar, the wrong temperature set, or even variations in
temperature between the top and bottom of the fridge.
Why use a Data Logger?
The WHO recommendation is for the temperature of vaccine
refrigerators to be continually monitored and for a record to be
taken at least once per day and documented on a chart.
Historically, a min/max thermometer would be used for this purpose.
However, this is laborious and prone to human error, so a small
data logger that sits next to the vaccines is an easier, more
Tinytag data loggers record data which is then downloaded to a
PC for analysis. The loggers can provide a comprehensive record of
a fridge's temperature history in a clear and simple graph. Many
data loggers feature indicators to show when the temperature
reaches unacceptable levels. Our medical data logger for example
has been designed to incorporate a red flashing LED, which is
triggered if the temperature falls outside a user-defined temperate
range. In this way it is immediately apparent to an observer if
there is a problem.
Data loggers in the Tinytag range are suitable for use in
medical freezers and cool boxes, as well as vaccine fridges.
Vaccine Monitoring Useful Tips
- Data loggers should be positioned alongside the vaccines,
preferably in the middle of a fridge where the temperature is most
- Ice build-up should be avoided because this reduces the
effectiveness of the refrigerator.
- During defrosting, an alternative refrigerator or an approved
cool box (also monitored with a data logger) should be used to
temporarily store the vaccines.
- When packaging and transporting vaccines to outlying clinics,
validated cool boxes and ice packs from a recognised medical
company should be used.
- Vaccines must be kept in the original packaging, wrapped in
bubble wrap or other insulation material and placed in a cool box
with cool packs as recommended by the manufacturers'
Calibration to Maintain Accuracy
The WHO recommends annual calibration checks. Gemini Data
Loggers offers a calibration service where data loggers can be
returned for a new battery and a traceable certificate of
World Health Organisation (2006) Temperature Sensitivity of