Rare but serious cases of blood clotting in people inoculated by the vector vaccines produced by AstraZeneca and Johnson&Johnson have been one obstacle to the international immunization campaigns against Covid-19.
Now researchers at the Goethe University in the western German city of Frankfurt think they may have identified the cause of the condition. In a preprint version of a scientific paper, a team led by Professor Rolf Marschalek said the problem resided in the vaccines’ spike protein penetrating the nucleus of cells of those inoculated. A “splice” or split in the protein, the team found, can lead to the extreme reaction.
With the m-RNA vaccines made by Pfizer/BioNTech and Moderna, proteins do not penetrate cell nuclei, which would explain why they have not been found to produce blood clotting.
“When these . . . virus genes are in the nucleus they can create some problems,” Marschalek told the Financial Times newspaper.
Reports of blood clotting after the administration of both AstraZeneca and Johnson & Johnson are very rare, but fears about side effects led many countries around the world to temporarily suspend rollouts of those vaccine. Johnson & Johnson is working with the Frankfurt researchers to correct the problem.
“[Johnson & Johnson] is trying to optimize its vaccine now,” Marchalek added. “With the data we have in our hands we can tell the companies how to mutate these sequences, coding for the spike protein in a way that prevents unintended splice reactions.”
Read the original pre-paper here