AstraZeneca has admitted for the first time in court documents that its Covid vaccine can cause a rare side effect, in an apparent about-turn that could pave the way for a multi-million pound legal payout.

The pharmaceutical giant is being sued in a class action over claims its vaccine, developed with the University of Oxford, caused death and serious injury in dozens of cases.

Lawyers argue the vaccine produced a side-effect which has had a devastating effect on a small number of families.

The first case was lodged last year by Jamie Scott, a father of two, who was left with a permanent brain injury after developing a blood clot and a bleed on the brain that has prevented him from working after he received the vaccine in April 2021.

The hospital called his wife three times to tell her that her husband was going to die.

AstraZeneca is contesting the claims but has accepted in a legal document submitted to the High Court in February that its Covid-19 vaccine “can, in very rare cases, cause TTS”.

TTS – which stands for Thrombosis with Thrombocytopenia Syndrome – causes people to have blood clots and a low blood platelet count.

Fifty one cases have been lodged in the High Court with victims and grieving relatives seeking damages estimated to be worth up to £100 million. AstraZeneca is contesting the claims.

AstraZeneca’s admission – made in a legal defence to Mr Scott’s High Court claim – follows intense legal wrangling.

It could lead to payouts if the drug firm accepts that the vaccine was the cause of serious illness and death in specific legal cases. The Government has pledged to underwrite AstraZeneca’s legal bills.

In a letter of response sent in May 2023, AstraZeneca told lawyers for Mr Scott that “we do not accept that TTS is caused by the vaccine at a generic level”.

But in a legal document submitted to the High Court in February this year, AstraZeneca said: “It is admitted that the AZ vaccine can, in very rare cases, cause TTS. The causal mechanism is not known.

“Further, TTS can also occur in the absence of the AZ vaccine (or any vaccine). Causation in any individual case will be a matter for expert evidence.”

Lawyers argue the AZ-Oxford vaccine is “defective” and that its efficacy has been “vastly overstated” – claims AstraZeneca strongly denies.

Scientists first identified a link between the vaccine and a new illness called vaccine-induced immune thrombocytopenia and thrombosis (VITT) as early as March 2021, shortly after the Covid-19 vaccine rollout began.

Lawyers for the claimants argue that VITT is a subset of TTS although AstraZeneca does not appear to recognise the term.

The Government has indemnified AstraZeneca against any legal action but has so far refused to intervene.

Kate Scott, Mr Scott’s wife, told the Telegraph: “The medical world has acknowledged for a long time that VITT was caused by the vaccine. It’s only AstraZeneca who have questioned whether Jamie’s condition was caused by the jab.

“It’s taken three years for this admission to come. It’s progress, but we would like to see more from them and the Government. It’s time for things to move more quickly.

“I hope their admission means we will be able to sort this out sooner rather than later. We need an apology, fair compensation for our family and other families who have been affected.

“We have the truth on our side and we are not going to give up.”

Sarah Moore, a partner at law firm Leigh Day who is bringing the legal claims, said: “It has taken AstraZeneca a year to formally admit that their vaccine can cause the devastating blood clots, when this fact has been widely accepted by the clinical community since the end of 2021.

“In that context, regrettably it seems that AZ, the Government and their lawyers are more keen to play strategic games and run up legal fees than to engage seriously with the devastating impact that their AZ vaccine has had upon our clients’ lives.”

In a statement AstraZeneca said: “Our sympathy goes out to anyone who has lost loved ones or reported health problems. Patient safety is our highest priority and regulatory authorities have clear and stringent standards to ensure the safe use of all medicines, including vaccines.

“From the body of evidence in clinical trials and real-world data, the AstraZeneca-Oxford vaccine has continuously been shown to have an acceptable safety profile and regulators around the world consistently state that the benefits of vaccination outweigh the risks of extremely rare potential side effects.”

The company is pointing out that product information relating to the vaccine was updated in April 2021, with the approval of the UK regulator, to include “the possibility that the AstraZeneca-Oxford vaccine is capable, in very rare cases, of being a trigger for” TTS.

The company does not recognise claims it has performed an about-turn in acknowledging the vaccine can cause TTS in court documents.

Independent studies show the AstraZeneca vaccine was incredibly effective in tackling the pandemic, saving more than six million lives globally in the first year of the rollout.

The World Health Organisation has said the vaccine was “safe and effective for all individuals aged 18 and above” and the adverse effect that has prompted the legal action was “very rare”.

The vaccine – heralded at its launch by Boris Johnson as a “triumph for British science” – is no longer used in the UK.

In the months after the rollout, the potentially serious side effect of the AstraZeneca jab was identified by scientists.

It was then recommended that under 40s be offered an alternative jab because the risk of the AstraZeneca vaccine outweighed the harm posed by Covid.

Lawyers representing families suing the drugs company argue that the vaccine was not as safe as individuals were entitled to expect. They are suing the pharmaceutical company, based in Cambridge, under the Consumer Protection Act 1987.

Mr Scott’s lawyers have argued that he suffered “personal injuries and consequential losses arising out of his sustaining vaccine induced immune thrombosis with thrombocytopenia (VITT) as a result of his vaccination on 23 April 2021, with the AstraZeneca Covid-19 vaccination”.

Official figures from the Medicines and Healthcare products Regulatory Agency (MHRA) show at least 81 deaths in the UK are suspected to have been linked to the adverse reaction that caused clotting in people who also had low blood platelets.

In total, almost one in five people who suffered from the condition died as a result, according to the MHRA’s own figures.

The Government runs its own vaccine compensation scheme but alleged victims claim the one-off payment of £120,000 is inadequate.

Figures obtained under a Freedom of Information request show that out of 163 payouts made by the Government, by February 2024, at least 158 went to recipients of the AstraZeneca vaccine.

The Vaccine Damage Payment Scheme gives compensation to those injured by vaccines or to bereaved next of kin.

Fewer than five people under the scheme received vaccines other than AstraZeneca.

AstraZeneca has previously argued in court papers that claims against the company are “confused” and “wrong in law”. 

In the defence filing, AstraZeneca said the benefit/risk profile of the vaccine was, and remains, positive.

AstraZeneca is the second largest publicly listed company in the UK with a market capitalisation of more than £170 billion.

Its chief executive, Sir Pascal Soriot, is the highest paid boss among FTSE 100 companies with earnings close to £19 million.

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