LONDON: The risk of developing side effects such as blood clots is much higher after infection with the SARS-COV-2 virus rather than after immunization with the Pfizer and Astrazeneca Covid-19 vaccine, according to a large British study published in the British medical journal (BMJ) on Friday .
The team led by researchers at the University of Oxford in the UK conducted research on thrombocytopenia – a condition with low platelet counts – and thromboembolism or blood clots followed the vaccination of covid-astrazeneca and pfizer-bionech.
Some of these events have caused the use of limited Oxford-Astrazeneca vaccines, known as Covishield in India, in a number of countries.
The researchers compared the level of bad events after vaccination with the same level of events after the positive SARS-COV-2 test results using data from more than 29 million people in the UK who received the first dose of both vaccines.
They concluded that with these two vaccines, for a short time interval after the first dose, there was an increased risk of several side effects related to blood that led to hospitalization or death.
“People must be aware of this increased risk after vaccination Covid-19 and immediately seek medical attention if they develop symptoms, but also aware that the risk is much higher and longer time period if they are infected with SARS-COV-2,” said Julia Hippisley-Cox, professor at Oxford University, and leads the writer of research papers.
The authors note that the risk of this poor incident is substantially higher and for a longer period of time, after the infection of the Coronavirus SARS-COV-2 rather than after the vaccine.
All Coronavirus vaccines are currently used have been tested in randomized clinical trials, which cannot be large enough to detect very rare side effects, they said.
When rare events are open, the regulator conducts risk-benefit analysis of the drug, to compare the risk of bad events if vaccinated versus the benefits of avoidance of diseases – in this case, Covid-19.
This study uses electronic health records collected routinely to evaluate short-term risks (within 28 days) of hospital receipts with thrombocytopenia, venous thromboemboli (VTE) and arterial thromboembolism (eating), using data collected from all over the United Kingdom between December 1, 2020 and April 24, 2021.
Other results studied were cerebral venous sinus thrombosis (CVST), ischemic stroke, myocardial infarction and other rare artery thrombotic events.
“This great study, using data on more than 29 million people who are vaccinated, have shown that there is a very small blob risk and other blood disorders after the first dose vaccination of Covid-19,” said Aziz Sheikh, a professor at Edinburgh University, and colleagues Paper writer.
“Even though it’s serious, this risk of the same results is much higher after the SARS-COV-2 infection,” Sheikh said.
The team consists of researchers based in the UK from Oxford, University of Leicester, Guys and St Thomas’ NHS Foundation Trust, National Research & Research Center Intensive Care, London School of Hygiene and Tropical Medicine, The University of Cambridge, University of Indonesia Edinburgh and Nottingham University .
The authors show some limitations for their research, including limiting the analysis for the first vaccine dose, windows exposure to short vaccination, and the potential error classification of results or exposure to acceptance where the patient is still in the hospital.
However, they believe that bias, if any, the possibility does not change with respect to each vaccine, so the comparison between vaccines cannot be affected.
“This research is important because many other studies, while useful, have been limited by small amounts and potential biases,” said Hippisley-Cox.
“Electronic health care records, which contain detailed recording vaccinations, infections, results and confuses, have given us a rich source of data to conduct a strong evaluation of this vaccine, and compared to the risks associated with Covid-19 infection,” he added.
This study underlines the importance of getting vaccinations to reduce the risk of freezing and the results of this bleeding in individuals, and because of the substantial public health benefits offered by Covid-19 vaccination, the researchers added.