The number of new infections with the Sars-Cov-2 coronavirus continues to decline, according to the Robert Koch Institute in Berlin. But researchers warn of false security. As long as there is no vaccine, further waves of infection are conceivable. This is known from the so-called "Spanish flu". Between 1918 and 1920 it raged in several phases of different degrees.
To avoid this, numerous laboratories around the world are working on vaccines. The Paul Ehrlich Institute in Langen has now given the green light for a combined phase 1 and phase 2 study to investigate RNA vaccines in healthy people. RNA stands for ribonucleic acids, i.e. molecules that carry genetic information.
Combine clinical studies from phases 1 and 2
Background: vaccines are first tested in animal experiments. If there are no concerns, follow phase 1 studies with a small number of subjects. This is all about security. The aim of phase 2 is to find the ideal dose of a vaccine. Attention is increasingly paid to side effects. Phase 3 then includes a larger number of participants. This can be several hundred to a thousand people. Ideally, it provides evidence of the desired effect and provides data for marketing authorizations.
In order to save time in the face of the pandemic, phases 1 and 2 are now combined. Scientists are investigating several RNA vaccines from the Mainz-based biotechnology company BioNTech in 200 healthy volunteers between the ages of 18 and 55 (phase 1). After a waiting period, other people are included who also belong to risk groups (phase 2).
RNA vaccines: Immunologically relevant proteins are created in the body
Different RNA vaccines are used. The molecules carry genetic information about all or part of the spike protein. These proteins are located on the outside of the corona virus shell and look like the spikes of a crown. They gave their names to pathogens. It is now known that spike proteins are required for the virus to infect cells at all.
The vaccine contains genetic data for the blueprint of these proteins. After spraying, cells begin to use this information to produce spike proteins without causing a disease. These proteins build up a protective immune response against Sars-Cov-2.
Some advantages of the RNA vaccine are known today from laboratory data and from animal experiments. These can be quickly produced in large quantities. You do not need high safety precautions and living material like in the production of flu vaccines in chicken eggs. In addition, RNA vaccines lead to a strong immune response. And last but not least, the tolerance of this vaccine is good.
Further approaches take time
So far there are no RNA vaccines on the market. Manufacturers are breaking new ground here. At the same time, other companies are examining established vaccine development structures. However, these strategies cost more time.
With live vaccines, patients receive small amounts of a coronavirus. This pathogen is derived from circulating Sars-Cov-2 pathogens. However, it was manipulated in such a way that illnesses no longer occur. Well-known examples of live vaccines are the vaccine against mumps, measles, rubella or varicella (chickenpox).
Chemically killed viruses also generate an immune response if they carry biologically active proteins on the surface: a principle known from flu viruses. The possibility of injecting only immunologically relevant fragments of the virus is also being researched. In both cases, infections do not occur.
Vector-based vaccines are an innovative strategy. They are made from viruses that are harmless to humans. These include the modified Measles Virus Ankara (MVA), the Vesicular Stomatitis Virus (VSV) or the Adenovirus (Ad). In the next step, parts of the Sars-Cov-2 genome are brought into this vector. It produces the associated protein in the body, for example the spike protein. The human immune system reacts to this. There are no approved vaccines based on this principle.
When does the vaccine come?
Manufacturers expect to produce the first RNA vaccines in six to 18 months. The level of uncertainty is great because it is not yet known how much a patient needs for the immune system to build up the necessary protection.
But that won't be enough. After all, all people worldwide should be vaccinated. No company will handle this alone; Cooperation is required. And Klaus Reinhardt, President of the German Medical Association, is calling for suitable concepts for staggered distribution to be developed now.
Artical:Ingenieur
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