@article{e9ffb682ad34449bac09eff3289e1bed,
title = "Second-dose ChAdOx1 and BNT162b2 COVID-19 vaccines and thrombocytopenic, thromboembolic and hemorrhagic events in Scotland",
abstract = "We investigated thrombocytopenic, thromboembolic and hemorrhagic events following a second dose of ChAdOx1 and BNT162b2 using a self-controlled case series analysis. We used a national prospective cohort with 2.0 million(m) adults vaccinated with two doses of ChAdOx or 1.6 m with BNT162b2. The incidence rate ratio (IRR) for idiopathic thrombocytopenic purpura (ITP) 14-20 days post-ChAdOx1 second dose was 2.14, 95% confidence interval (CI) 0.90-5.08. The incidence of ITP post-second dose ChAdOx1 was 0.59 (0.37-0.89) per 100,000 doses. No evidence of an increased risk of CVST was found for the 0-27 day risk period (IRR 0.83, 95% CI 0.16 to 4.26). However, few (≤5) events arose within this risk period. It is perhaps noteworthy that these events all clustered in the 7-13 day period (IRR 4.06, 95% CI 0.94 to 17.51). No other associations were found for second dose ChAdOx1, or any association for second dose BNT162b2 vaccination. Second dose ChAdOx1 vaccination was associated with increased borderline risks of ITP and CVST events. However, these events were rare thus providing reassurance about the safety of these vaccines. Further analyses including more cases are required to determine more precisely the risk profile for ITP and CVST after a second dose of ChAdOx1 vaccine.",
keywords = "Adult, BNT162 Vaccine/adverse effects, COVID-19/epidemiology, ChAdOx1 nCoV-19/adverse effects, Humans, Prospective Studies, Purpura, Thrombocytopenic, Idiopathic/chemically induced, Scotland, Thromboembolism/chemically induced, Vaccination/adverse effects",
author = "Simpson, {Colin R} and Steven Kerr and Katikireddi, {Srinivasa Vittal} and Colin McCowan and Ritchie, {Lewis D} and Jiafeng Pan and Stock, {Sarah J} and Igor Rudan and Tsang, {Ruby S M} and {de Lusignan}, Simon and Hobbs, {F D Richard} and Ashley Akbari and Lyons, {Ronan A} and Chris Robertson and Aziz Sheikh",
note = "Funding Information: A.S. is a member of the Scottish Government Chief Medical Officer{\textquoteright}s COVID-19 Advisory Group and its Standing Committee on Pandemics; the UK Government{\textquoteright}s New and Emerging Respiratory Virus Threats (NERVTAG) Risk Stratification Subgroup; and was a member of AstraZeneca{\textquoteright}s COVID-19 Thrombocytopenia Taskforce. All roles are remunerated to A.S. or his institution. C.R.S. declares funding from the MRC, NIHR, CSO, and New Zealand Ministry for Business, Innovation and Employment and Health Research Council during the conduct of this study. SVK is co-chair of the Scottish Government{\textquoteright}s Expert Reference Group on COVID-19 and ethnicity, is a member of the Scientific Advisory Group on Emergencies (SAGE) subgroup on ethnicity and acknowledges funding from a NRS Senior Clinical Fellowship (SCAF/15/02), MRC (MC_UU_00022/2) and CSO (SPHSU17). C.R. is a member of the Scottish Government Chief Medical Officer{\textquoteright}s COVID-19 Advisory Group, SPI-M, MHRA Vaccine Benefit and Risk Working Group. All other authors report no competing interests. Funding Information: EAVE II is funded by the Medical Research Council (MR/R008345/1) with the support of BREATHE—The Health Data Research Hub for Respiratory Health [MC_PC_19004], which is funded through the UK Research and Innovation Industrial Strategy Challenge Fund and delivered through Health Data Research UK. This research is part of the Data and Connectivity National Core Study, led by Health Data Research UK in partnership with the Office for National Statistics and funded by UK Research and Innovation (grant ref MC_PC_20058). Additional support has been provided through Public Health Scotland and Scottish Government DG Health and Social Care. FDRH acknowledges part support as Director of the NIHR Applied Research Collaboration (ARC) Oxford Thames Valley, and Theme Lead of the NIHR OUH BRC. We thank Dave Kelly from Albasoft Ltd for his support with making primary care data available and Frances Burns, Mathhew Thankur, Wendy Inglis-Humphrey, Vicky Hammersley, Dom Balharry and Laura Brook, Morag Edwards and Laura Gonzalez Rienda for their support with project management and administration. We thank the EAVE II Public Advisory Group. Our thanks to Prof. Jenni Quint, Prof. Rustam Al-Shahi Salman and Dr. Quentin Hill for their help with reviewing code lists. Publisher Copyright: {\textcopyright} 2022, The Author(s).",
year = "2022",
month = aug,
day = "15",
doi = "10.1038/s41467-022-32264-6",
language = "English",
volume = "13",
pages = "4800",
journal = "Nature Communications",
issn = "2041-1723",
publisher = "Nature Publishing Group",
number = "1",
}