Vaccine development Will the oral vaccination against Covid-19 come soon?
Scientists from the University of Würzburg and the biopharmaceutical company Aeterna Zentaris are working on the development of an oral vaccination against Covid-19. Preclinical development, which should pave the way for the first clinical studies in humans, has already started.
Company on the subject
Würzburg – If Professor Thomas Rudel and the biopharmaceutical company Aeterna Zentaris have their way, there could possibly be significant reinforcements in the fight against the global corona pandemic in the future: a vaccination that is not administered with a syringe, but in the form of a capsule, which can easily be swallowed.
Thomas Rudel holds the chair for microbiology at the Julius Maximilians University of Würzburg (JMU). A year ago he had the idea for the oral vaccination. His approach has been used millions of times as protection against typhoid infection for many years. The oral typhoid vaccine is based on a special strain of bacteria, Salmonella Typhi Ty21a.
Rudel and the scientists in his laboratory are now working with the same strain of bacteria. However, with one major modification: “We programmed the bacteria to produce Sars-Cov-2 antigens,” explains the microbiologist. Rudel was supported by the microbiologist Dr. Birgit Bergmann. Protected from gastric acid attack in a capsule, the bacteria are supposed to develop their effect in the human small intestine after they have passed through the stomach. The scientific approach assumes that the bacteria can present the antigens to the immune system there.
Special cells in the intestinal wall are supposed to ensure that bacteria and the antigens are absorbed by immune cells and transported further into lymphoid tissue. There they could in turn activate other cells of the immune system – so-called B and T cells – and set an immune response in motion. Rudel hopes that, if successful, this immune response will be so strong that all human mucous membranes will be put on alert and, as a result, coronaviruses will be prevented from entering the body there.
Built-in safety anchor
There is a simple reason why the bacteria developed by Rudel’s team should not produce one, but two antigens: As has been shown in recent months, Sars-Cov-2 often mutates. This could mean that an antigen is only weakly effective if the virus should have changed accordingly. The second antigen could therefore serve as a “safety anchor”: It is based on a gene that has been shown to mutate only rarely.
Comparatively cheap to manufacture, easy to administer and relatively stable even at normal temperatures: These are a few advantageous properties that such a new type of vaccine could have once it is ready for the market. If successful, this would also make it attractive for use in countries in which it is difficult to guarantee a cold chain with temperatures as low as minus 70 ° C without interruption.
Experience from previous vaccine development
Thomas Rudel and his team are developing the vaccine strains with financial support from Aeterna Zentaris and will carry out preclinical work; after successful completion of the preclinical phase, the pharmaceutical company would be responsible for the subsequent clinical tests. Rudel is confident that the necessary permits could be obtained relatively quickly. A few years ago, Aeterna Zentaris had been working with a similar process on a vaccine against prostate cancer, which was about to start clinical trials and had been officially approved for clinical examination. The team can now build on this experience.
Despite all the euphoria: There is no guarantee that an oral vaccination against Covid-19 will soon be available in pharmacies, warns Rudel. After all, many active ingredients have failed even at a late stage of development because they were not sufficiently effective or had unexpected and undesirable effects. That risk always exists. Rudel will be waiting all the more eagerly for the coming months.