Johnson & Johnson covid vaccine
© AFP / PHILL MAGAKOE
In this file photo taken on February 18, 2021 a healthcare worker holds a dose of the Johnson & Johnson vaccine against the COVID-19 coronavirus at the Klerksdorp Hospital.
A group of German scientists claims to have found the cause of the rare blood clots linked to the Oxford/AstraZeneca and Johnson & Johnson coronavirus vaccines - and they say the jabs could be altered to prevent the problem

The research, led by Professor Rolf Marschalek from Goethe University, in Frankfurt, was published on Wednesday. It suggests the problem lies with the adenovirus vector technology used in the vaccines. Viral vector vaccines use a modified version of a different virus to deliver important instructions to the nucleus of cells so as to produce a spike protein and trigger an immune response in the body.

Dr Marschalek and his team believe some parts of the spike protein split apart and create 'mutant' versions that trigger the blood clots, in what the paper termed the "Vaccine-Induced Covid-19 Mimicry" syndrome. The study suggests vaccine manufacturers could alter the sequence of the spike protein to prevent unintended splitting and "increase the safety of these pharmaceutical products."

"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", Marschalek said in an interview with the Financial Times.

The researchers go on to suggest that all mRNA-based vaccines, such as those developed by BioNTech/Pfizer and Moderna "should represent safe products," because they use a different technology. Instead of putting a weakened or inactivated virus into the cells, mRNA vaccines teach them how to make a protein without it entering the cell nucleus.

The paper, published on preprint platform Research Square, has not yet been peer reviewed by a journal.

In recent months, the AstraZeneca and Johnson & Johnson vaccines have been linked to rare, but serious - and, in some cases, fatal - blood clots.

The first EU fatality linked to the Johnson & Johnson Covid-19 shot was registered in Belgium this week, where a 37-year-old woman died. The country has suspended vaccinations using the jab for anyone under the age of 41. More than 140 cases were recorded among those who received the AstraZeneca vaccine in the European Economic Area. The UK registered more than 300 cases and 56 deaths.

Nine instances of blood clots in patients administered the AstraZeneca vaccine have also been reported in the past week in Australia. In the US, the Centers for Disease Control and Prevention (CDC) announced earlier this month that a "plausible causal association" had been discovered between the Johnson & Johnson vaccine and 28 cases of blood clots.

A raft of countries across the world have suspended use of the jabs, while others have restricted their usage to older age groups.

Issues have also recently been reported with the mRNA-based vaccines. The CDC announced earlier this month that an investigation would be conducted into reports of heart issues in young, mostly male patients who had received either the Moderna or Pfizer-BioNTech vaccines. Three cases of hemophilia, a rare disorder affecting the blood's ability to clot, were also reported among recipients of Pfizer-BioNTech's Covid-19 vaccine in France.