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A health worker (C) is preparing a dose of Pfizer-BioNTech Covid-19 vaccine at a vaccination clinic set up on 31 March 2021 at the Derby Arena in Pride Park in Derby, England.
Oli Scarff / AFP via Getty Images
The risk of developing blood clots is about the same
Pfizer
‘s and Moderna’s Covid – 19 vaccines as in
AstraZeneca
‘s, according to a study released Thursday.
Researchers at Oxford University, the same university that helped develop the medicine business
AstraZeneca
vaccine, found that the rare blood clot, known as cerebral venous thrombosis, occurred in four out of every million people who received the vaccines from the drug company.
Pfizer
and biotechnology
Modern.
That equates to five out of a million people after the first dose of AstraZeneca-Oxford vaccine, they said.
In both cases, the risk of blood clots is much higher in those who contract the Covid-19 virus. CVT occurred in 39 out of a million patients, the researchers said.
‘We have reached two important conclusions. First, Covid-19 significantly increases the risk of CVT and adds it to the list of blood clotting problems that cause this infection. Second, the Covid-19 risk is higher than what we see with current vaccinations, even for those under 30; something that needs to be considered when considering the balance between risks and benefits for vaccination, ‘said Paul Harrison, professor of psychiatry and head of the translation neurobiology group at the University of Oxford.
The study has major implications, given the way regulators respond to blood clot disorders. In Europe, AstraZeneca has restricted the use of vaccines, and the US is now reviewing the pharmaceutical vaccine
Johnson & Johnson,
which is manufactured using a similar process as the AstraZeneca vaccine, and also caused blood clots.
Both the Pfizer and Moderna vaccines are produced by the mRNA process, using the molecules in cells that control protein production to teach the immune system to make coronavirus antibodies.