Scientists have discovered a link between a complication of the COVID-19 vaccine and the complication caused by a rare ‘cold blood disease’.
The research, led by Flinders University and international experts, deepens our understanding of vaccine-induced immune thrombocytopenia and thrombosis (known as VITT).
Following the first waves of the COVID-19 pandemic in 2020, governments around the world implemented a range of infection control measures, including a mass vaccination program.
Since then, more than 13.5 billion doses of Covid vaccines have been administered worldwide, saving more than a million lives in Europe alone, a recent World Health Organization study found.
Although effective at reducing the severity of COVID-19 infection, in 2021 it was found that a vanishingly small percentage of individuals who received adenoviral vector-based vaccines, which use a harmless virus as the delivery system, experienced vaccine-induced immune thrombocytopenia and thrombosis (VITT). ).
VITT is characterized by life-threatening thrombosis, or blood clotting, in multiple body sites.
VITT turned out to be caused by an unusually dangerous autoantibody in the blood, directed against a protein called platelet factor 4 (or PF4).
In separate 2023 research, researchers from Canada, North America, Germany and Italy described a nearly identical condition involving the same PF4 antibody that was fatal in some cases following a natural infection with the adenovirus (common cold).
Flinders University researchers Doctor Jing Jing Wang and Flinders Professor Tom Gordon, head of immunology at SA Pathology in South Australia, led an earlier study in 2022, cracking the molecular code of the PF4 antibody and identifying a genetic risk factor linked to an antibody gene called IGLV3.21*02.
Now the Flinders group has collaborated with this international group of researchers to discover that the PF4 antibodies in both adenovirus infection-associated VITT and classical adenoviral vector VITT share identical molecular fingerprints or signatures.
The research will also have implications for improving vaccine development, says Flinders University researcher Doctor Wang, first author of the new paper published in the New England Journal of Medicine.
“These findings, using a completely new blood antibody targeting approach developed at Flinders University, indicate a common trigger factor on virus and vaccine structures that initiates the pathological pF4 antibodies,” Professor Gordon explains.
The research will also have implications for improving vaccine development, the researcher says
FATHER
“Indeed, the pathways of lethal antibody production in these conditions should be virtually identical and have similar genetic risk factors.
“Our findings have the important clinical implication that lessons learned from VITT apply to rare cases of blood clotting after adenovirus infections (a common cold), and that they also have implications for vaccine development,” he said.
The opinion of the editors
The finding is important for understanding the impact of the global vaccination campaign, but it should be emphasized how extremely rare complications from the vaccine are.
Numerous studies suggest that the benefits of vaccination far outweigh the risks for the majority of people.
In Britain, the safety of vaccines in both adults and children has been extensively assessed by the independent Medicines and Healthcare products Regulatory Agency (MHRA).
And Covid is here to stay.
NHS England is urging high-risk groups to get vaccinated against COVID-19 this spring.
People at increased risk of severe disease can receive the vaccine, including people who are 75 years or older (as of June 30, 2024), people with weakened immune systems or who live in a care home for the elderly.