Breakthrough Could Extend Vaccine Shelf Life

Researchers in Switzerland report a new method to improve the thermal stability of vaccines, a breakthrough that may extend the shelf-life of life-saving inoculations.

Nearly half of all vaccines go to waste due to the logistical obstacles involved in transporting them to diverse regions of the world. Most vaccines require strict temperature regulation from the manufacturing line to human injection. But maintaining a constant temperature along the supply chain can be challenging, even more so in developing regions with limited transport infrastructure and unreliable electricity. 

But a recent collaboration between scientists from ETH Zurich’s Macromolecular Engineering and Organic Chemistry Labs and entrepreneurs from Colorado-based Nanoly Bioscience has resulted in a safe, versatile platform to increase the thermal stability of vaccines.

The team developed a new type of hydrogel, the details of which were just published in the journal Science Advances. The gel is based on a biocompatible, synthetic polymer known as PEG that serves as a protective, cloaking device for very large complex molecules such as the proteins found in vaccines, antibodies, or gene therapies. The packaging works kind of like a molecular Tupperware, encapsulating the proteins and keeping them separated. It enables the proteins to withstand a higher range of temperature fluctuations. Instead of the traditional +2 to +8 °C (35 to 45 °F) range for the cold chain, encapsulation allows for a range of 25 to 65 °C (75 to 150 °F). Most importantly, the encapsulated cargo is simply released by adding a sugar solution, enabling easy on-demand recovery of the vaccines at their point of use.

In addition to a higher rate of vaccine viability, the real game changer of this new biomedical hydrogel technology is the potential economic effect it could have on reducing costs and health risks associated with the cold chain. “In 2020, the overall market for cold chain services (from manufacturing to distribution) was $17.2 billion and forecasted to rise,” according to the paper. Rising costs pose potentially dire consequences for public health and public trust if vaccines arrive via a compromised cold chain.

“Most vaccines are sensitive to hot and cold. This creates a large barrier for global immunization campaigns, because vaccine distribution and administrative costs often exceed the costs of production,” says Bruno Marco-Dufort, a doctoral researcher in Professor Mark Tibbitt’s Macromolecular Engineering lab at ETH Zurich. While more investment will be needed to shore up the cold chain, encapsulation offers a cost-saving solution that could be put towards production of more vaccines and thus, save more lives.

Further research, safety studies, and clinical trials are necessary before the hydrogels can be implemented for vaccine distribution. Their more immediate use is for transporting heat-sensitive enzymes used in cancer research, for example, or protein molecules for research in lab settings.