According to a study, mRNA vaccines can lead to the formation of unwanted proteins to a very small extent. So far, however, there is no evidence that negative effects have occurred with the mRNA vaccines already used against Corona, write researchers led by Anne Willis from the British University of Oxford in the journal “Nature”.
Nevertheless, the phenomenon should be avoided in future vaccines, as it could potentially lead to negative effects such as reduced effectiveness or side effects.
No reason to worry
German experts speak of interesting results, but see no reason for concern. “The effect described, if true, is not dangerous or worrying and most likely has nothing to do with general vaccination reactions or with the side effects of mRNA vaccines,” said Julian Schulze zur Wiesch from the University Hospital Hamburg-Eppendorf (UKE). Overall, the mRNA vaccines are safe.
His colleague Marina Rodnina from the Max Planck Institute for Multidisciplinary Natural Sciences in Göttingen sees it similarly: There is currently no evidence that such protein pieces produced by vaccination are associated with undesirable effects in humans. However, if production can be adjusted to avoid the phenomenon, "this should definitely happen for the future use of mRNA technology."
mRNA vaccines contain the building instructions - the so-called mRNA - for a component of the virus against which humans are to be protected. A type of machine for protein construction (ribosomes) reads these mRNA molecules in the human cells and, on this basis, assembles a virus protein. This then stimulates the immune system to produce antibodies against the virus.
In order to be particularly effective, the mRNA in the vaccines is slightly modified by the manufacturer, as Anne Willis and her team write in "Nature". These changes can cause the protein construction machine to slip slightly when reading the mRNA blueprint, resulting in unwanted proteins being created.
Willis' team was able to show in mice for the Corona vaccine from Biontech (BNT162b2) that an immune response occurs against such unwanted proteins. The researchers also observed such an immune response to a small extent in a third of 21 human volunteers, without any of them complaining of side effects. The research team was also able to show how such unintended effects can be avoided in the future.