The first approved vaccine against the SARS-CoV-2 coronavirus is the mRNA (or mRNA, messenger RNA) vaccine of the pharmaceutical company "Pfizer/Bionteck". The US Federal Medicines Agency (FDA) has approved it for use, vaccination has begun in Great Britain, and Bulgaria is preparing special refrigerators for the first 125,000 doses.
On the basis of the same technology, the "Moderna" vaccine was created, which has completed the last third phase of testing and is expected soon after that of "Pfizer".
Why these vaccines are approved for use and what is the mRNA technology, explained Prof. Dobroslav Kyurkchiev - head of the Laboratory of Clinical Immunology of UMBAL "St. Ivan Rilski", with a publication on the Facebook page of the Organization of patients with rheumatic diseases in Bulgaria.
Prof. Dobroslav Kyurkchiev
Both vaccines contain the so-called messenger RNA (mRNA). It is important to know that it is "non replicated", that is, it cannot be reproduced. This means that mRNA is a genetic element that does not come into contact with our DNA, cannot integrate into our genome, nor replicate in our cells. A few days after the vaccination, everything that was injected into us will be broken down by our cells. Also, mRNA introduces absolutely no viral matter into our body. That way there is really no chance of getting infected by anything.
The messenger RNA in both vaccines can only "create" one protein, which is part of the SARS-Cov-2 virus and is known as the S-protein. The messenger RNA is then degraded
As part of the vaccine, the mRNA is wrapped in a lipid bubble. It is in terms of the composition and structure of this lipid bubble that the main differences between the vaccines of the two companies.
I. The vaccine is injected subcutaneously, and from this there are several results: the lipid bubble merges with the membranes of the cells in the muscles and falls into them. Inside the cell it is broken down and the mRNA is detected and creates the S-protein. It is perceived as foreign and the cells display it on their surface to be seen by some of the cells of the immune system that act against it. Another part of the S-protein is thrown out. This is one of the most impressive properties of the mRNA used - to create protein S to be thrown out. This is a technological pride of "Moderna", enshrined in their patent. The same thing happens with the other vaccine.
II. Subcutaneous injection leads to the attraction of many specialized cells that actively take up the liposome as well as the S-protein released from the cells in the muscles. The ingested liposome has the same fate as the other vaccine. The ingested discarded S-protein is then processed and also displayed by these specialized cells, but in a different way, triggering other levels of the immune system. In addition, the specialized cells produce many substances with antiviral action (interferons).
The end result is that an immune response is triggered against this S-protein by both antibodies and T cells. When the virus carrying the S-protein arrives, the immune system is ready to destroy it.
“With these vaccines there is absolutely no risk of affecting the genes, not to mention nonsense like chipping by vaccination. We only have mRNA that just makes a protein and breaks it down. She could not serve for anything else. In my opinion, from an immunological point of view, the approach is simply admirable.
There is virtually no experience of the effects of these vaccines on people with autoimmune diseases. The only connection to practice is observations of how people with autoimmune diseases fared through COVID-19. It is generally believed that in autoimmune diseases the infection is not more severe and that patients with autoimmune diseases are not at risk. Therefore, it is logical that we have a similar situation with vaccines that mimic aspects of the disease.
On the other hand, however, autoimmune diseases are different, there are more than 80 of them and each one has its own characteristics. Furthermore, a disease progresses and affects individuals differently because some people have damaged organs and others do not. And here is the place for treating doctors to assess the benefit/risk ratio for each particular patient, because they know his disease. With any vaccination in people with autoimmune diseases, there are two dangers:
One is to give a boost to the disease. Autoimmune phenomena have been described in COVID-19, as in almost all infections. That is, it is possible. However, on the other hand, aluminum adjuvants, which the current two vaccines do not have, are usually to blame for the "boosts". But a cross-reaction of the immune system with the viral protein during immunization and a simultaneous reaction with its own proteins that resemble it is possible.
In general, it is believed that in about 10% of patients with autoimmune diseases, a "boost" of the disease can be observed during vaccination. Therefore, it is recommended that in this group, vaccination should be done with caution and should only be administered against "severe infectious diseases".
Immunosuppressive therapy, suppressing the immune response, can make the vaccine ineffective. For the flu vaccine, there is data that it does not work in 47% of immunized patients with autoimmune diseases.
I don't think that those who have had COVID-19 need to be vaccinated - at least not a few months after the illness. In my opinion, the danger of autoimmune impulses in this case would increase, writes the expert.