University College London Hospitals (UCLH) NHS FT have taken part in a national study, which has enhanced the understanding of the novel vaccine-induced immune thrombocytopenia and thrombosis (VITT), associated with the Oxford/AstraZeneca vaccine. It has allowed researchers to understand the symptoms, signs and outcomes of these patients even more.
Consultant Haematologist Professor Marie Scully, and Dr Will Lester from University Hospitals Birmingham NHS FT, first identified VITT in the UK. Dr Sue Pavord at Oxford University Hospitals (OUH) NHS FT led the research paper, which reported on the first 220 cases of definite and probable VITT in the UK.
Recent research shows that the overall mortality rate of those presenting to hospitals with definite or probable VITT was 23%. Almost all patients who had their first vaccine, experienced VITT within five and 30 days after their vaccine. This didn’t change for someone’s sex, and 41% had no previous medical diagnoses, with 85% being less than 60 years old. Overall incidence in those under 50 was estimated to be 1 in 50,000 – which was consistent with reports from other countries.
Professor Scully, who is also Professor of Haemostasis and Thrombosis at UCL Institute of Cardiovascular Science, said: “As a new condition we are still learning about how best to diagnose and manage VITT, but as time goes on, we have been able to refine our treatment approaches and improve rates of survival and chance of recovery. This continuous learning in real time has been made possible thanks to collaboration between colleagues across the UK.”
They found that the chance of death was increased to 73% in patients with a very low platelet count and intracranial haemorrhage, following blood clots in the brain.
Researchers also found evidence that non-heparin-based blood thinners should be used to tackle blood clotting in cases of VITT, and that use of intravenous immunoglobin was associated with better outcomes.
Dr Pavord, a Consultant Haematologist at OUH, said: “We have worked relentlessly to understand and manage this new condition, so that the hugely successful vaccine roll out can continue, which is the most viable solution to the global pandemic.
“It’s important to stress that this kind of reaction to the Oxford-AstraZeneca vaccine is very rare. In those aged under 50, incidence is around one in 50,000 people who have received the vaccine.”
The new research paper is published in the New England Journal of Medicine, based on cases of VITT presented by 182 consultant haematologists from 96 NHS trusts. It follows on from the understanding of the condition published in an April 2021 NEJM paper, which was led by Professor Scully, reporting on 23 early cases of VITT.
UCLH’s Dr Richard Perry also published a study earlier this month in the Lancet on cases of cerebral venous thrombosis (CVT) when it is caused by VITT. CVT is the most common and severe manifestation of VITT.