The researchers examined data on 29 million people in England, where concerns have risen following the death of a BBC presenter related to the vaccine.
The risk of blood clotting after receiving the first doses of AstraZeneca or Pfizer COVID-19 is much lower than that of the virus, according to a large-scale study by researchers at Oxford University.
Fears about rare cases of coagulation disease have led some countries to rule out or limit the launch of the AstraZeneca jab developed by Oxford, and the UK recommends that healthy people under the age of 40 have alternative vaccines.
The study published in the medical journal BMJ examined data on 29 million people in England vaccinated for the first time between December and April.
A very small increase in the risk of some clotting conditions was found that could lead to hospitalization or death shortly after the first doses of the AstraZeneca and Pfizer vaccines.
But it was concluded that the risks of most conditions were “substantially higher and longer” after COVID-19 infection.
The problem came to light this week when a coroner found on Thursday that a 44-year-old BBC presenter, Lisa Shaw, had died from a blood clot in her head as a rare complication of a first dose of ‘AstraZeneca.
The study’s lead scientist Julia Hippisley-Cox, a professor of clinical epidemiology at Oxford University, told BBC Radio 4 that Shaw’s death was “very sad”, but “these are very rare cases and the vast majority of patients will be absolutely fine with these vaccines. ”
Reports have focused on the link of the AstraZeneca jab to cerebral venous sinus thrombosis (CVST) or blood clots in the brain.
The study estimated that for 10 million people who received the AstraZeneca puncture, there were seven additional cases, compared with 20 in people with COVID infection.
For blood clotting in a vein (venous thromboembolism), the scientists estimated that there were 66 additional cases among 10 million who received the AstraZeneca puncture, but 12,614 among those who had the virus.
The study found that AstraZeneca sting was associated with excessive cases of thrombocytopenia or low levels of blood clotting platelets, with an additional 107 cases per 10 million people. But the number of those infected with the virus was 934.
The Pfizer vaccine was related to an excess of 143 strokes per 10 million, while COVID was related to 1,699 strokes in excess.
Hippisley-Cox stressed that the increase in risks associated with strokes was only short-term, while virus infection was associated with an increased risk throughout the 28-day period examined.
For example, Pfizer’s stroke increased the risk of stroke from 15 to 21 days, he said.
To date, the UK has reported 6.6 million confirmed cases of COVID, while 132,000 have died.
During the pandemic peaks, the country recorded about 1,000 COVID-related deaths a day.
Since a highly praised vaccination campaign that has resulted in the vaccination of more than 70% of people aged 16 and over, fewer people have succumbed to the virus, although a recent rise in infections and deaths is worrying.