European scientists, together with foreign colleagues, found out why some people have immunity against COVID-19, despite the fact that they have never been sick with it.
What is the essence of the discovery?
The scientific group of Rostislav Bely is researching adjuvants - special substances that are part of modern vaccines. They enhance the action of the antigen (“pathogen”) contained in the vaccine, so that a sufficiently strong immune response occurs in the body, but vaccination remains safe. About three years ago, researchers set themselves the task of obtaining and testing antibodies against the pathogen MERS (Middle East Respiratory Syndrome), a coronavirus that is a relative of SARS-CoV-2. Scientists chose it, because MERS is considered one of the most dangerous infectious diseases - mortality from it reaches 35%. An outbreak of the previously unknown MERS began in 2012, but was extinguished.
The researchers obtained antibodies against the MERS pathogen in laboratory mice and rabbits. And when the COVID-19 pandemic began, they continued their research and recently published a preprint - a preliminary version of an article with new results, which has not yet been independently verified, and which may still be subject to certain changes. But the main author has no doubts that the article will be accepted and published in one of the scientific journals according to all the rules.
Scientists have found that one of the proteins on the surface of the SARS-CoV-2 virus has a specific region that is extremely similar to a similar region of the MERS pathogen, as well as the first SARS-CoV and other known coronaviruses. Scientists call these sites "conservative".
Previously, this area was not given special importance, since in a protein molecule it is, as it were, hidden inside and should not play any important role. But now it turned out that when the virus tries to get inside the cell, the structure of the protein changes, and it is this site that plays a key role. And it is to him that the human body produces antibodies - that is, immunity.
What does this mean in practice?
This means that a person who has had some kind of disease caused by one of the coronaviruses - or the very dangerous MERS-CoV, or another that causes a banal runny nose, has antibodies against the pathogen COVID-19. Scientists call this phenomenon "cross-immunity." The presence of such immunity does not mean that a person cannot get COVID-19, but, most likely, he will suffer it in a milder form than without cross-immunity. At the same time, it is important to understand that only part of ARVI is caused by coronaviruses, therefore, not every ARVI guarantees that a person will have immunity against COVID-19.
What does the vaccine have to do with it?
Another interesting takeaway from the work is that it is possible to create a vaccine that will be effective against all known coronaviruses. And perhaps even against those that will appear in the future. To do this, the vaccine must target exactly this antigen - common to all coronaviruses. However, if such a vaccine is created, then it, most likely, will not protect against the disease. But it will make it easier, at least it will not be fatal. If it targets a different region of the protein - a more variable one, then the vaccine will be "seasonal" - it will have to be updated annually, as is done with influenza vaccines.