Three years after the freeze-free concept was reported at the September 2014 meeting of the WHO PQS Committee, the current expectation of availability remains ‘sometime next year’ and it appears that no product has passed the pre-qualification (E004/VC02-VP.1) testing yet.
The current status of this product was presented at the last Technet Conference by WHO/PQS. During the resulting discussion, I noted five issues that seem to require attention:
- The outside dimensions and weight of the current prototype products are greater than the carriers used for forty years. We should see comparative data on dimensions, weight of the new and existing carriers because health workers will carry them, often for long distances. Evidence that the increased weight and bulk is operationally feasible should be confirmed by field testing.
- Freeze-protection in current carrier designs employs a built-in thermal buffer between icepacks and vaccines. The vaccine carrier including the thermal buffer begins the PQS test at +43C when the vaccine load is added at +5C. Evidence was not shared at the Technet meeting that in fact the new products can cool down the test load to below +10C within 8 hours and what is the maximum temperature during cool down?
- WHO mentioned, in the context of fixed thermostat refrigerators, that replacement of existing equipment by new models will proceed at a ‘natural’ replacement rate under GAVI CCEOP. If this method of replacement is also followed for vaccine carriers that often survive for 10 years, the renewal process will be too slow to avoid a considerable rate of freezing damage.
- One question raised at Technet has been raised without a satisfactory answer many times in the last 3 years: “Why is the freeze-free carrier the only solution pursued by global stakeholders”. For example, freezers that deliver their frozen icepacks at a few degrees below zero instead of -20C are feasible, but not explored. Phase change materials as a substitute for water/icepacks have been rejected by PQS without clear evidence.
- The current PQS focus on passive cooling vaccine carriers with icepacks is likely to be overtaken by active-cooled solutions based on adsorption or thermoelectric technology. This solution, in the form of Global Good’s ‘Indigo’ product, gives outreach teams 5 days or more autonomy and streamlines the process of daily short range activities by switching cooling on and off. In spite of these benefits the product has no specification nor pre-qualification test in PQS because it is an active cooler, not passive. The current process for establishing a new product is said to be more than two years.
These questions among others reveal a weakness in the way that the global immunization community handles technology changes for immunization services. Innovation and optimization are treated as ‘solutions hunting for a problem’ instead of operational challenges to the development and growth of immunization – that call for new or improved technologies. Your opinions on how WHO/PQS might strengthen and accelerate this process will be, i I am sure, very welcome !