Almost half of vaccines end up in the bin. “Let’s think of it as an egg”

Some vaccines (including those against COVID-19) require a specific storage temperature and have a relatively short shelf life. This means that the preparations can go to waste. The number of disposal is likely to be reduced – the hydrogel technology is expected to help.

1. The storage conditions of some vaccines are quite restrictive – the preparations require a very low temperature
2. This applies in particular to mRNA vaccines against COVID-19, i.e. Pfizer and Moderna
3. When the preparation is subjected to a higher temperature, it is no longer usable and must be disposed of
4. More current information can be found on the Onet homepage.

Almost half of the vaccines produced in the world are wasted

Almost half of all vaccines produced in the world are wasted. This is mainly due to logistical obstacles related to transport across the globe. Most vaccines need to be stored at a strictly defined temperature: from production, through transport and storage, to injection into the human arm. Maintaining such a cold chain is quite a challenge. For example, in sub-Saharan Africa and other developing regions, limited infrastructure and unreliable electricity systems often prevent the correct and effective delivery of preparations to consumers.

To meet the challenge, scientists from Macromolecular Engineering and Organic Chemistry Labs at ETH Zurich and specialists from Nanoly Bioscience in Colorado have developed a safe and comprehensive platform to increase the thermal stability of vaccines. Their goal was to significantly improve vaccine distribution and reduce the economic costs of maintaining the cold chain.

“Let’s think of it as an egg,” says Bruno Marco-Dufort, a PhD student involved in the study. – At room temperature or in the refrigerator, the egg retains its protein structure, but when it enters boiling water or a frying pan, this structure changes permanently. The same is true of proteins in a vaccine – when exposed to certain temperatures, they stick together and re-cooling cannot reverse this denaturation. Just like it is impossible to “boil” the “eggs”.

Hydrogel will solve the problem?

So, instead of changing mother nature, Marco-Dufort and his colleagues developed a new type of hydrogel based on a biocompatible synthetic polymer PEG (polyethylene glycol) that serves as a protective “cloak” for very large, although invisible to the naked eye, complex molecules such as just proteins in vaccines, but also antibodies, etc.

The packaging of particles in such a hydrogel acts like a plastic container for storing food – it encapsulates proteins and keeps them separate, preventing them from sticking together even at unfavorable temperatures.

As a result, proteins withstand greater fluctuations in temperature. Instead of the traditional range from +2 to +8 degrees C, such hermetic separation allows them to survive unchanged even at temperatures of 25-65 degrees C. start up quickly just before serving.

In addition to extending the lifetime of vaccines, this technology has the potential to provide enormous economic benefits. “In 2020, the overall market for cold chain services (from production to distribution) amounted to $ 17,2 billion, and this amount is forecast to increase” – emphasize the authors of the publication. Rising costs have potentially dire consequences for public health.

«Most vaccines are sensitive to heat and cold. This creates a big barrier to global vaccination campaigns as the distribution of formulations and administrative costs often outweigh production costs, explains Marco-Dufort. – Encapsulation offers an effective and fairly inexpensive solution, and the money saved can be used to produce more vaccines, thus saving more lives ».

However, before hydrogels can reach vaccine manufacturers and distributors, they must undergo a series of safety tests and clinical trials.

The authors of the idea hope that their solution can also be used to transport heat-sensitive enzymes, for example used in cancer research, or protein molecules for laboratory research (PAP).

Katarzyna Czechowicz

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