Assessing Case Fatality on Cases of Thrombosis With Concurrent Thrombocytopenia Following COVID-19 Vaccine AstraZeneca (Vaxzevria) in the United Kingdom: A Review of Spontaneously Reported Data

12 Pages Posted: 11 Aug 2021 Last revised: 29 Jun 2022

See all articles by Samantha Lane

Samantha Lane

Drug Safety Research Unit; School of Pharmacy and Biomedical Sciences, University of Portsmouth

Saad Shakir

Drug Safety Research Unit

Date Written: June 21, 2022

Abstract

Introduction: Events of thrombotic thrombocytopenia syndrome (TTS) were reported very rarely following COVID-19 Vaccine AstraZeneca (Vaxzevria). Clinical and demographic characteristics of the affected people including the outcomes of TTS events need to be examined using available information to better understand aspects of this association.

Aim: To analyse clinical and demographic information of TTS events including calculating the case fatality of reported cases of TTS by age and sex, using spontaneously reported data from the United Kingdom’s (UK’s) Yellow Card spontaneous reporting system of suspected adverse drug reactions.

Methods: TTS events reported to the Yellow Card scheme were extracted at weekly time points between 12 May 2021 and 25 May 2022. Cumulative numbers of TTS cases and deaths were recorded for each weekly interval, overall and stratified by age, sex, and vaccine dose.

Results: Up to 25 May 2022, 443 cases (81 fatal; 18.28%) had been reported in the UK. Events more frequently occurred following the first vaccine dose. No trends were observed for case fatality overall, or by age or sex.

Conclusion: In the UK, case fatality of TTS events reported to the MHRA following Vaxzevria has been approximately 17-18% since May 2021. There were no statistical differences in fatality based on age or sex. Most reports followed the first vaccine dose; none have been reported following a third dose to date, though Vaxzervia was not recommended for third dose of COVID-19 vaccine in the UK. TTS remains very rare, and benefits of vaccination outweigh the risks.

Note: Funding: No external funding was received for the completion of this study.

Declaration of Interests: All authors have completed the Unified Competing Interest form (available on request from the corresponding author) and declare: The Drug Safety Research Unit (DSRU) is a registered independent charity (No. 327206) associated with the University of Portsmouth. The DSRU receives donations and grants from pharmaceutical companies; however, the companies have no control over the conduct or publication of its studies. The DSRU has received grants to conduct unconditional studies on the Oxford/AstraZeneca COVID-19 vaccine and is in negotiations to receiving grants for conducting CPRD studies for Pfizer, Moderna, and Janssen COVID-19 vaccines. The DSRU has conducted benefit-risk studies on products for COVID-19, including remdesivir, lopinavir/ritonavir, chloroquine and hydroxychloroquine, and convalescent plasma. Professor Shakir is the principal investigator for an active surveillance study for the Oxford/AstraZeneca vaccine, but this assessment is unrelated to this study. Professor Shakir has been a member of Data Safety Monitoring Boards for Ipsen, Biogen, and Diurnal. None of these companies have any involvement with COVID-19 vaccines. Professor Shakir was invited by AstraZeneca to advise on the events of thrombosis with thrombocytopenia with the COVID-19 vaccine and to be a member of an advisory committee on a safety study of the Oxford/AstraZeneca vaccine in Europe. Samantha Lane has no conflicts of interest with regard to this study.

Keywords: COVID-19, vaccination, adverse events, thrombotic thrombocytopenia syndrome, treatment

Suggested Citation

Lane, Samantha and Shakir, Saad, Assessing Case Fatality on Cases of Thrombosis With Concurrent Thrombocytopenia Following COVID-19 Vaccine AstraZeneca (Vaxzevria) in the United Kingdom: A Review of Spontaneously Reported Data (June 21, 2022). Available at SSRN: https://ssrn.com/abstract=3899805 or http://dx.doi.org/10.2139/ssrn.3899805

Samantha Lane (Contact Author)

Drug Safety Research Unit ( email )

Bursledon Hall
Blundell Lane
Southampton, Hampshire SO31 1AA
United Kingdom

School of Pharmacy and Biomedical Sciences, University of Portsmouth ( email )

Portsmouth
Hampshire
United Kingdom

Saad Shakir

Drug Safety Research Unit ( email )

Bursledon Hall
Blundell Lane
Southampton, Hampshire SO31 1AA
United Kingdom

Do you have a job opening that you would like to promote on SSRN?

Paper statistics

Downloads
78
Abstract Views
533
Rank
575,499
PlumX Metrics