Mission Rabies field teams in Malawi used adhesive temperature monitors during a four week mass vaccination drive. Two different Timestrip temperature monitors were used to alert the teams to the critical temperature thresholds of 0°C and 30°C. As freezing rapidly damages vaccines, each vaccine box was labelled with a monitor that indicates the immediate crossing of the lower threshold through a clear colour change. At the high temperature end, as damage is related to both the temperature achieved and the time of exposure, each cooler box was equipped with a monitor that showed the crossing of the upper threshold over time.
The World Health Organisation stresses the importance of maintaining the cold chain for temperature sensitive vaccines, and in the case of rabies vaccines, storage should be between 2° and 8° Celsius. However, achieving this tolerance in canine mass vaccination projects is difficult as cold chain management remains one of the most significant logistical hurdles project managers have to overcome.
In the initial trials, one third of the vaccination teams participating reported an exposure of the vaccines to temperatures above 30°C for more than 4 hours, and on nine occasions, the teams reported a temperature drop to 0°C or below. These temperature breaches are the result of proximity to ice packs and exposure to high outside temperatures, and highlight the importance of continuous monitoring of temperature throughout the supply chain.
The use of Timestrip temperature indicators gives early visual clues and raises awareness of storage conditions among field workers. Work continues to optimise the indicators for such applications.
Timestrip CEO Reuben Isbitsky said: “We are delighted that our practical, cost effective temperature and time monitoring technology has been put to such a worthwhile use in this application. We are confident that many similar applications exist, and will fully support any such initiatives.”