A coronavirus infection presents a much higher risk of developing a blood clot than a first dose of either the AstraZeneca or the Pfizer jab, a study has found.
The research used findings from more than 29 million people who were vaccinated with first doses of either jab.
The study showed although there was an increased risk of having a blood clot after having the first doses of either vaccine, it was much greater in someone who had tested positive for COVID-19.
The researchers are fully independent from the University of Oxford team that worked with AstraZeneca to develop that particular vaccine.
Fears over blood clots have led to the restricted use of the Oxford AstraZeneca vaccine in a number of countries.
Advertisement
The researchers, writing in the British Medical Journal, found for short time intervals after the first does there are increased risks of some blood, or blood-vessel, related events leading to hospitalisation or death.
However, they also wrote that that the risk of these adverse events is substantially higher and for a longer period of time, following infection from coronavirus.
More on Covid-19
Julia Hippisley-Cox, professor of clinical epidemiology and general practice at the University of Oxford, lead author of the paper, said: “People should be aware of these increased risks after COVID-19 vaccination and seek medical attention promptly if they develop symptoms, but also be aware that the risks are considerably higher and over longer periods of time if they become infected with SARS-CoV-2.”
All of the coronavirus vaccines currently in use have been tested in randomised clinical trials, which are unlikely to be large enough to detect very rare adverse events.
When rare events are uncovered, regulators perform a risk-benefit analysis of the medicine to compare the risk of the adverse reaction, such as a blood clot, against the benefits of avoiding the disease – in this case COVID-19.
For this paper, the researchers used routinely collected electronic health records to evaluate the short-term risks (within 28 days) of hospital admission from blood clots.
They used data collected from across England between 1 December 2020 and 24 April 2021.
Professor Hippisley-Cox said: “This research is important as many other studies, while useful, have been limited by small numbers and potential biases. Electronic healthcare records, which contain detailed recording of vaccinations, infections, outcomes and confounders, have provided us with a rich source of data with which to perform a robust evaluation of these vaccines, and compare to risks associated with COVID-19 infection.”
The research was carried out by a team from the University of Oxford, University of Leicester, Guys and St Thomas’ NHS Foundation Trust, the Intensive Care National Audit & Research Centre, the London School of Hygiene and Tropical Medicine, the University of Cambridge, the University of Edinburgh and the University of Nottingham.
A 76-year-old man has been arrested on suspicion of administering poison at a summer camp which led to eight children being taken to hospital, police said.
Police received reports of children feeling unwell at a summer camp in Canal Lane, Stathern, Leicestershire, on Monday.
Paramedics assessed eight children, who were taken to hospital as a precaution and have all now been discharged.
The suspect was arrested at the camp and remains in custody on suspicion of administering poison with intent to injure/aggrieve/annoy.
Detective Inspector Neil Holden said: “We understand the concern this incident will have caused to parents, guardians and the surrounding community.
“We are in contact with the parents and guardians of all children concerned.
“Please be reassured that we have several dedicated resources deployed and are working with partner agencies including children’s services to ensure full safeguarding is provided to the children involved.
More from UK
“We also remain at the scene to carry out enquiries into the circumstances of what has happened and to continue to provide advice and support in the area.
“This is a complex and sensitive investigation and we will continue to provide updates to both parents and guardians and the public as and when we can.”
The force said it has referred itself to the Independent Office for Police Conduct (IOPC) over what it said was the “circumstances of the initial police response”.
There is no evidence that malign activity was responsible for yesterday’s outage of air traffic control systems, the transport secretary has said.
Heidi Alexander said she has spoken with the chief executive of National Air Traffic Service (NATS), Martin Rolfe, and added that what happened was an isolated incident.
NATS has apologised for the IT problems after thousands of passengers suffered extensive travel disruption during one of the busiest times of the year.
The technical glitch led to more than 150 flight cancellations, leaving airlines reacting furiously.
Image: Transport Secretary Heidi Alexander
Ms Alexander wrote on X: “I have spoken with NATS CEO Martin Rolfe who provided further detail on yesterday’s technical fault.
“This was an isolated event and there is no evidence of malign activity.
“I know that any disruption is frustrating for passengers.
“Flights are now resumed and I am grateful to airlines who are working hard to get people to where they need to be.
“I will continue to receive regular updates. Passengers should check with airlines before travelling.”
Officials said a “radar-related issue” caused the air traffic control failure.
A spokesperson for NATS said: “This was a radar-related issue which was resolved by quickly switching to the back-up system during which time we reduced traffic to ensure safety.
“There is no evidence that this was cyber related.”
The problem occurred at NATS’ control centre in Swanwick, Hampshire, and affected the vast majority of England and Wales.
Aviation analytics company Cirium said 84 departures and 71 arrivals were cancelled to or from UK airports up to 10pm on Wednesday, with several flights diverted to other European airports.
Please use Chrome browser for a more accessible video player
5:06
Travel expert Paul Charles: This is a major outage
There was limited disruption on Thursday, with a handful of British Airways flights cancelled because aircraft and crew were out of position.
Heathrow and Gatwick airports said they had resumed normal operations.
Affected passengers are unlikely to be entitled to compensation as the disruption was outside of airlines’ control, but they will be able to claim expenses for a reasonable amount of food and drink, a means to communicate and overnight accommodation if required.
Image: Martin Rolfe in 2023. Pic: PA
Ryanair has called on Mr Rolfe to resign, claiming “no lessons have been learnt” since a similar systems outage in August 2023.
The airline’s chief operating officer Neal McMahon said: “It is outrageous that passengers are once again being hit with delays and disruption due to Martin Rolfe’s continued mismanagement of Nats.”
Airlines have reacted furiously after a technical glitch in air traffic control systems led to more than 150 flight cancellations.
The National Air Traffic Service (NATS) has apologised for the IT problems – and said systems were back up and running 20 minutes after the “radar-related issue” was detected at 4.05pm.
But with thousands of passengers suffering extensive travel disruption, during one of the busiest times of the year, airline executives have warned this isn’t good enough.
Please use Chrome browser for a more accessible video player
1:01
Departures resume after ATC problem
Ryanair’s chief operating officer Neal McMahon has called for NATS chief executive Martin Rolfe to resign – and claimed Wednesday’s incident was “utterly unacceptable”.
He said: “It is outrageous that passengers are once again being hit with delays and disruption due to Martin Rolfe’s continued mismanagement of NATS.
“It is clear that no lessons have been learnt since the August 2023 NATS system outage, and passengers continue to suffer as a result of Martin Rolfe’s incompetence.”
Mr McMahon was referring to a glitch that affected more than 700,000 passengers two years ago – and said that, if Mr Rolfe refuses to step down, the government should intervene.
“Heidi Alexander must act without delay to remove Martin Rolfe and deliver urgent reform of NATS’ shambolic ATC service, so that airlines and passengers are no longer forced to endure these preventable delays caused by persistent NATS failures,” he added.
The Department for Transport says Ms Alexander does not have any direct control over NATS – and no powers over staffing decisions at the service.
Image: Martin Rolfe in 2023. Pic: PA
EasyJet’s chief operating officer David Morgan added: “It’s extremely disappointing to see an ATC failure once again causing disruption to our customers at this busy and important time of year for travel.
“While our priority today is supporting our customers, we will want to understand from NATS what steps they are taking to ensure issues don’t continue.”
NATS is yet to comment on the calls for Mr Rolfe’s resignation – but has stressed that the glitch is not believed to be “cyber related”.
“This was a radar-related issue which was resolved by quickly switching to the back-up system during which time we reduced traffic to ensure safety,” a spokesperson had said.
Departures at airports across the country have now resumed – but passengers are being urged to check with their airline before heading to terminals.
Please use Chrome browser for a more accessible video player
5:06
Travel expert: This is a major outage
John Carr, from Stourbridge, was on his way from Heathrow to Norway to help arrange his brother’s wedding when he discovered his flight was cancelled after checking in.
“I’m pretty gutted,” he said. “We’ve got loads of stuff in the suitcases to set up the venue, because we’re obviously flying to Norway. We’ve got the wedding rehearsal to do. It’s quite stressful.”
Liberal Democrat leader Sir Ed Davey called for an urgent investigation and also referred to the “utterly unacceptable” disruption two years earlier.
“With thousands of families preparing to go on a well-earned break, this just isn’t good enough. The public deserve to have full confidence in such a vital piece of national infrastructure.”
Follow The World
Listen to The World with Richard Engel and Yalda Hakim every Wednesday
Airlines may have to provide compensation, although there are exemptions for “extraordinary circumstances”, according to the UK’s Civil Aviation Authority.