The advantage is that this thermostable corona vaccine can be stored and transported at room temperature; a solution, especially in warm low- and middle-income countries.

Things that are freeze-dried: food for astronauts. emergency rations. And, just maybe, some future corona vaccines. Researchers have succeeded in producing a freeze-dried specimen that resembles a mint green cotton candy. A vaccine with enormous potential.

What is freeze drying?
Freeze drying in a method of removing water from a product. The substance to be dried is first frozen, so that the water turns into ice. This ice is then extracted from the substance through a process called sublimation (the direct transition from solid to gaseous state).

In a new study Scientists report that they have successfully developed a freeze-dried corona vaccine. The vaccine is mint green in color and looks a bit like cotton candy. The vaccine consists of several ingredients, including water, specialized liposomes that carry a synthetically produced version of the coronavirus spike protein, and a small amount of sugar that protects the vaccine during freeze-drying.

Milestone

The research is quite a milestone. Although a vaccine using freeze-dried liposomes is still relatively far off, it does have enormous potential. If researchers succeed in developing this further, freeze-dried corona vaccines can be stored and transported at room temperature. This is particularly beneficial in warm low- and middle-income countries.

cold chain

Most of our current corona vaccines must be delivered refrigerated. This means that they must be stored and transported at low temperatures; otherwise they lose their efficacy. “When we started our project, the first COVID-19 vaccines were just being rolled out,” said researcher Jonathan Lovell. “It was regularly in the news that the vaccines had to be stored under cold conditions and that this was an enormous logistical challenge. Such a cold chain may not always be feasible, especially in low- and middle-income countries. And so we started to see if we could manufacture a thermostable corona vaccine.”

Indeed, the researchers seem to be on the right track. “After freeze-drying, the vaccine was stable at elevated temperatures,” says researcher Moustafa Mabrouk. “We have shown that it can withstand room temperature for at least a week and can tolerate even higher temperatures.”

Mice

The next step was to study the extent to which the corona vaccine still effectively protected against COVID-19. “We first reconstructed the vaccine by adding water,” explains Mabrouk. “When we then tested it in mice, it elicited a strong antibody response and provided protection against the coronavirus.”

A liposome-based corona vaccine is currently being tested on humans in South Korea. This vaccine, called EuCorVac-19, contains slightly different ingredients than the vaccine used in the current study. But the researchers do not rule out the possibility that EuCorVac-19 can also be freeze-dried. “While we haven’t tested this yet, I think EuCorVac-19 may be susceptible to this,” Lovell says. “In that case, we could make the vaccine thermostable; a particularly beneficial property.”