Risks of blood clots from Covid "much higher" than from vaccine 1 year ago

Risks of blood clots from Covid "much higher" than from vaccine

The results are in.

A new study has found that the risk of a blood clot associated with the Covid vaccine is far less than the actual virus.


There is an increased risk of being admitted to hospital or dying from a blood clot by contracting the virus rather than if you have taken the vaccine.

The risk of this outcome from Covid is "much higher" than people who have had their first dose of AstraZeneca or Pfizer, researchers say.

The research looked at over 29 million people aged over 16 who had had their first dose in England between December and April, finding that the risk of a clot was nine times higher if they were to contract Covid.


Professor Aziz Sheikh, who was involved in the study, said that the increased risk of thrombocytopenia, which causes blood to clot, in this vaccine is similar to other vaccines commonly used across the UK, including the flu vaccine.

It is estimated that out of every 10 million people vaccinated with AstraZeneca, there would be 107 cases of thrombocytopenia in the 28 days post-vaccination.

For a person who contracts Covid, this risk rises to 934 cases.

There was also an association between those with the Pfizer jab and an increased risk of stroke, but again this was much higher if you were to get Covid, 10 times higher.


There have been an estimated 143 extra cases of ischaemic stroke per 10 million people with Pfizer, compared with 1,699 cases in those with Covid-19.

When it comes to blood clotting in a vein, there were around 66 more cases per 10 million people vaccinated with AstraZeneca, compared with around 12,614 diagnosed with Covid.

There were no associations with blood clots in an artery for either vaccine, but there were 5,000 cases of this associated with Covid.


Professor Julia Hippisley-Cox, professor of clinical epidemiology and general practice at the University of Oxford, said the increased risks they detected were only for a short time after vaccines, compared to a longer period if infected with the virus.

She said: "For stroke, with Pfizer it was just 15 to 21 days after vaccination that there was an increased risk.

"And for thrombocytopenia with the AstraZeneca it was eight to 14 days. So they were very specific, short periods of time, whereas the associations with infection appeared to be generally over a whole 28-day period after the infection."

BBC presenter Lisa Shaw died due to complications from the AstraZeneca vaccine, a coroner concluded on Thursday.


Shaw, who worked from BBC Radio Newcastle, died in May, just over three weeks after she was vaccinated.

The 44-year-old's death, MailOnline reported, is believed to be the first time a Covid jab has officially been ruled the underlying cause of death in the UK.