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The Biontech / Pfizer and Moderna vaccines are considered effective agents against Sars-CoV-2. Both are based on mRNA technology, in which genetic material is funneled into human cells. Could this change the human genome? A fact check.
It seems too good to be true: a revolutionary biotechnology could save humanity from the coronavirus. The first Biontech / Pfizer vaccine approved in the West uses so-called mRNA. Before that, there was no approved vaccine of this type anywhere in the world. Not only was the vaccine developed in record time, but it is 95 percent so effective that many scientists did not expect. Moderna’s competitor product is equally effective and is also mRNA-based.
The abbreviation mRNA stands for messenger ribonucleic acid, which is also known as messenger RNA. The mRNA vaccines consist of the genetic information of one or more specific components of the virus, in the case of the coronavirus it is the spike protein or parts of it. During vaccination, this genetic information is channeled into human cells. Once the mRNA has reached human cells, thanks to the blueprint stored in it, they can recreate the virus protein and present it to the immune system. This triggers an immune response and ultimately the vaccinated person has a very low risk of developing Covid-19.
But the fact that Biontech / Pfizer’s BNT162b2 is a genetic vaccine causes some discomfort. Fears circulate on social media that the mRNA in the vaccine could alter the human genome, which is inactive as DNA in the cell nucleus. Some opponents of vaccination even use the mRNA vaccine compared to genetic engineering of plants.
Klaus Cichutek, president of the Paul Ehrlich Institute (PEI), responsible for vaccine safety, had already warned against “scare tactics” by vaccine opponents in this context. “The warnings about genetic damage are incorrect and cause unfounded fears,” Cichutek said in an interview with the “Neue Osnabrücker Zeitung.” Fears that new mRNA vaccines could change the genetic material of humans “would not correspond to the state of scientific knowledge.”
But what is this evaluation based on? An overview of the most important points:
The mRNA does not come into contact with human DNA.
An important point: everything that is important in vaccination happens in the cell, but it has nothing to do with the nucleus of the cell, there is only the human genome, stored in the form of DNA. “The mRNA has … almost no chance of reaching the DNA, which is isolated in the cell nucleus,” vaccine researcher Carlos Guzmán of the Helmholtz Center for Infection Research told “Zeit”. Inside the cell, the mRNA from the vaccine and the DNA from the genome do not come into contact with each other.
MRNA and DNA have different chemical structures.
There is another exclusion criterion: “The integration of RNA into DNA is not possible due to the different chemical structure, among other things,” writes the PEI. Due to chemical differences, the two biomolecules do not fit together and cannot form chains. The most important deviations: DNA consists of a double strand, RNA consists of a single strand. They both also use different sugar molecules as a framework. RNA and DNA also differentiate into one of the four organic bases that form the ladder-like “rungs” of biomolecules.
MRNA can be converted to DNA, but not so easily
But couldn’t mRNA also become DNA and then integrate into the genome? In fact, a conversion is possible, this is done by viruses such as the AIDS pathogen HIV, which transcribes its genetic material from RNA into DNA. To do this, the virus uses an enzyme called reverse transcriptase. However, this is not present in human cells. “There is also no evidence that mRNA taken up by cells in the body after vaccination is transcribed into DNA,” the PEI writes.
MRNA is a natural component of the human cell.
The mRNA contained in vaccines is not a foreign substance, but something that is used permanently in human cells. It is also crucial for the production of other proteins, as this part of the DNA in the cell nucleus is read and sent as messenger RNA to the cell’s protein factories. Since the mRNA only has a messenger function, it quickly breaks down again. It happens so fast that it was long doubted that mRNA could be used medicinally.
The virus also works on mRNA.
The mRNA vaccine only mimics what the virus would do on its own: when Sars-CoV-2 enters the cell, its genetic information stored as RNA (coronaviruses are RNA viruses) is also transmitted to the protein factories of the cells. where then the components of the virus are recreated. Including the aforementioned spike protein, the model of which is in the mRNA vaccine. Other viruses, such as cold viruses, also use the same principle.
There is already experience with mRNA vaccines
The Biontech BNT162b2 vaccine is the first mRNA vaccine to be approved. But research on the therapeutic use of mRNA has been going on for about three decades. In the past, mRNA vaccines have also been developed and investigated in clinical studies. The Tübingen-based company Curevac, for example, had previously tested an mRNA-based rabies vaccine in humans.
MRNA vaccines have advantages over DNA vaccines
However, there are also vaccines that are not based on mRNA, but on DNA, and are randomly integrated into the genetic makeup of the human cell. actually like “potential security risk “, as in the Pharmaceutical Directory The yellow list is. But the fact that this cannot happen with mRNA is what researchers Deborah Fuller and Peter Berglund evaluated as a “comparative advantage of mRNA (relative to DNA vaccines)”, as they write in their study on mRNA vaccines. published in June.
Conclusion: “There is no risk of mRNA integrating into the human genome”, judges the PEI. However, this does not mean that mRNA vaccines generally pose no risk. It is true that previous studies show that vaccines are well tolerated. According to the company, some of the vaccinated test persons experienced side effects such as fatigue, headache, and joint pain and redness at the injection site. Similar reactions are also known from other vaccines and they are also a sign that the vaccine is doing what it is supposed to do: activating the immune system. However, what is missing so far is information on rare, possibly serious side effects, as these only become apparent after vaccination of many people and a longer observation period.
