You won't need a refrigerator

Vaccines quickly lose their properties when stored outside the refrigerator, so they are difficult to transport to remote regions. At temperatures above 8 °C, the proteins in the vaccines begin to break down, making them ineffective. As a result, millions of children around the world are left without vital vaccinations.

However, scientists have found a way to prevent the rapid decomposition of vaccine components. They placed protein molecules in a silicon dioxide shell – such a structure remains intact even when heated to 100 ° C or stored at room temperature for up to three years.

The technique developed by a group from the University of Bath in collaboration with the University of Newcastle, UK, was called "ensilication". It was first tested in the laboratory two years ago, and has now demonstrated its effectiveness in the real world.

In their new study, the authors mailed ensilicated and conventional tetanus vaccine samples from Bath to Newcastle (the distance between the cities is approximately 500 km, postal delivery usually takes one or two days). In Newcastle, the resulting vaccines were injected into mice and the immune response was evaluated. After the encylicated vaccine, an immune system reaction developed, demonstrating its activity. In mice injected with unprotected doses of the vaccine, no immune response was detected, which indicates the destruction of the drug during transportation.

The data obtained show that ensilication allows preserving not only the structure of vaccine proteins, but also the main function – immunogenicity.

This study was conducted using tetanus toxoid, which is part of the DPT vaccine (against diphtheria, tetanus and pertussis), which is administered three times to young children. Scientists plan to make and test a heat-resistant vaccine against diphtheria, and then whooping cough. The main goal is to create a silicate shell for the trivalent DPT vaccine in its entirety, so that every child in the world can receive it without having to rely on the cold chain. Currently, the cold supply chain requires that the vaccine be cooled all the time from the moment of production to the final destination.

Silicon dioxide is an inorganic non-toxic material, and, according to the authors, the ensilicated vaccines can be preserved and used for 5-15 years. They believe that the work will end with the adoption of a technology that allows silicon dioxide to protect the proteins of all childhood vaccines, as well as other protein-based drugs, such as antibodies and enzymes. Then vital drugs will become stable and more accessible, this will help to completely defeat the diseases that are prevented with the help of vaccines.

Currently, up to 50% of vaccine doses are disposed of, as they become unusable due to exposure to suboptimal temperatures. According to the World Health Organization, in 2018, 19.4 million children did not receive routine life-saving vaccinations.

Article A.Doekhie et al. Ensilicated tetanus antigen retains immunogenicity: in vivo study and time-resolved SAXS characterization published in the journal Scientific Reports.

Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru based on the materials of the University of Bath: Ground-breaking research makes childhood vaccines safe in all temperatures.