A father-of-two who claims he suffered a brain injury after receiving the AstraZeneca Covid-19 vaccine is bringing a High Court challenge against the pharmaceutical giant over allegations it was caused by a “defect” in the jab.

Lawyers for Jamie Scott claim he developed “vaccine-induced immune thrombotic thrombocytopenia” (VITT) – a rare blood-clotting condition – after being injected in April 2021.

The 47-year-old has been left with “very serious injuries including speech difficulties, reduced cognition, memory and processing” and is seeking compensation over the alleged impact of the vaccine, according to a court document.

AstraZeneca, which is understood to be defending against the claim, is also accused of having “vastly overstated” the efficacy of the jab developed with Oxford University.

The drugs giant said patient safety was its “highest priority” and that the UK’s medicines regulator had granted full marketing approval for the vaccine named Vaxzevria.

According to the court filing setting out details of Mr Scott’s claim, he was first vaccinated on April 23 2021 at a clinic in Warwickshire.

Ten days later he suffered from a headache, vomiting and impaired speech and was taken to hospital by ambulance, Mr Scott’s barrister Hugh Preston KC wrote.

He received “acute inpatient treatment”, including brain surgery, over the next few weeks and now requires “multi-disciplinary rehabilitation”, Mr Preston said.

The lawyer added: “He struggles to complete simple domestic tasks, he has symptoms on the right side and visual difficulties, he has concentration difficulties, and suffers fatigue.”

Mr Preston said Mr Scott was unable to independently care for his two young children for long periods of time and could not drive.

He said the AstraZeneca vaccine “did in fact expose recipients of the vaccine to the risk of VITT” and that “the defect in the product was the propensity of the product to cause VITT”.

The barrister added that Mr Scott suffered VITT “as a consequence of his receipt of the product”, which he said was no longer available in the UK.

The Oxford/AstraZeneca Covid-19 vaccine was approved in the UK in December 2020, and jabs were initially rolled out among the older and the most vulnerable in society.

The jab was developed on a not-for-profit basis, with some three billion doses being distributed worldwide.

On April 7 2021, the Medicines and Healthcare Products Regulatory Agency (MHRA) issued updated information on the “possible risk of extremely rare and unlikely to occur specific types of blood clots” following vaccination with the AstraZeneca jab.

The regulator said the benefits of vaccination “continue to outweigh any risks” but advised “careful consideration be given to people who are at higher risk of specific types of blood clots because of their medical condition”.

A spokeswoman for AstraZeneca said: “Patient safety is our highest priority and regulatory authorities have clear and stringent standards to ensure the safe use of all medicines, including vaccines.

“Our sympathy goes out to anyone who has lost loved ones or reported health problems.

“From the body of evidence in clinical trials and real-world data, Vaxzevria 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 Medicines and Healthcare products Regulatory Authority has granted full marketing approval for Vaxzevria for the UK based on the safety profile and efficacy of the vaccine.”