Although there are lots of potential vaccine candidates on the horizon, for the large majority of these vaccines there will be a requirement for very accurate temperature-controlled storage, shipment and handling methods. It appears that most prospective vaccines will require transportation and distribution well below freezer temperatures, the most promising candidates requiring close to -68 degrees C cryogenic conditions.

At present, even if the vaccine was made available tomorrow, the logistic support network does not exist to handle such distribution, even in developed countries.

This exact problem was faced during the Ebola crisis, in which the approved vaccine had to be shipped close to -68 degrees C levels. Across the African continent, there were limited options for dry-ice and a lack of extensive laboratory freezers. This presented a major logistical problem.

The world is facing a far bigger challenge than Ebola at present, and certainly simple reusable ice packs with water-based Eutectic solution between -50 degrees C and -68 degrees C could be a useful tool in order to help resolve this logistical challenge.

The ice packs can be recharged and used multiple times, hence eliminating the need for dry ice. This technology could represent a vital logistical tool in both storing and shipping the vaccine across the less developed world. It will also help in developed countries, as demand may well end up exceeding the current production capacity for dry-ice.

Utilising central distribution centres, such as airports and other suitable storage facilities / central distribution hubs, it may be possible to provide up to 48 hours safe transport and handling of any potential COVID-19 vaccines, even for the most remote locations.

The solution is in the form of the aforementioned custom-made water-based Eutectic -65 degree C ice packs and matching insulated boxes for distribution. The main aim of the Eutectic solutions is to enable users to freeze the ice packs in standard laboratory ULT freezers. In a similar manner to how a person may freeze standard water ice packs, in order to use them in a picnic basket or drinks cooler. This concept would allow for approved vaccines to be safely transported from main distribution centres.

As the solution is water-based, it represents no hazardous issues, which offers many advantages for both handling, as well as transportation. As the eutectic material is water based, any shape or configuration of ice pack design can be easily filled.

Another major issue that may be faced across several of the developing countries is unreliable electricity supply and power cuts. Using the eutectic solution inside of a standard ULT freezer can additionally provide a stand-by capability, if and when the power is lost. This stand-by capability can also aid in reducing the excessive refrigeration compressor start/stop penalties, hence allowing for improved reliability and energy savings. Most importantly, however, it offers a method to bridge the gap during power shortages to ensure that no valuable vaccine stock is lost.

The writer is with Phase Change Material Products Limited. He can be contacted at z.ure@pcmproducts.net