A new PQS freeze protected vaccine carrier has been approved. The incorporation of this new carrier would solve a serious problem but at a considerable cost. PATH estimates that 2 million carriers would have to be replaced.
Several years ago we had been working on a freeze protection method which incorporated water as a phase change barrier between the stored vaccines and the ice packs. This appears to be the same freeze protection mechanism incorporated in the PQS approved carrier. The water barrier in our freeze protection method was created by a water pack which would have the same height and width as a .6 liter pack however it would be much thinner, only about 5 mm thick. When the ice packs are loaded the barrier packs would be clipped against the frozen ice packs. In the carrier the barrier would sit between the stored vaccines and the cold ice packs. The barrier packs would be stored at room temperature.
As a consequence of not having to replace the carrier this technique would be much less costly to implement. Using water pack barriers also offers the flexibility of working with different sized carriers. In addition it would reduce the amount of plastic waste produced with replacement.
Sun Frost did not go further with the commercialization of this technique because we did not have the funds for implementation at that time. We would be glad to consult with any company interested in implementing this technique.
Larry Schlussler Phd