Question explored with the scientific record
Conversation so far
- 1 Was the Astra Zeneca covid vaccine actually withdrawn due to evidence of it causing blood clots?
- 2 How many people got VITT per million doses in each country?
Answered on this page ↓
How many people got VITT per million doses in each country?
The short version: the evidence you provided does not contain per-country VITT incidence rates per million doses. The question cannot be answered from these records.
The evidence you gave me covers the mechanism of VITT, case reports, and a comparison of two adenoviral vaccines, but it does not include a single table or study that reports VITT incidence per million doses broken down by country. The previous answer in this conversation cited rates from Norway (1 in 26,500), the UK (1 in 70,000), and Germany (1 in 90,800), but those figures came from the earlier retrieval, not from the records in front of me now. I cannot carry them forward. The only incidence-like numbers in this retrieval are from a UK nationwide analysis that found a small increase in venous thromboembolism 8 to 14 days after ChAdOx1 vaccination (incidence rate ratio 1.10, 95% CI 1.02-1.18) [11], but that is not a VITT-specific rate and it is not broken down by country.
The 2025 comparison study of 86 Ad26.COV2.S and 220 ChAdOx1 VITT cases [5] gives detailed clinical characteristics but no denominator. It tells you what VITT looks like when it happens, not how often it happens per dose in any country. The case reports [1, 2, 3, 4, 6, 7, 8, 9, 10] describe individual patients but contribute nothing to population incidence.
What this means for you: the per-country VITT rates you are asking about exist in the published literature (the UK Medicines and Healthcare products Regulatory Agency, the European Medicines Agency, and national health authorities all published them), but this particular retrieval did not surface them. The question is answerable from public health surveillance data, just not from the records I was given.
My call: I cannot give you the per-country VITT incidence rates because the evidence provided does not contain them. Confidence: high that the records do not answer this question.
Sources used 11
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Venous Thromboembolism and Mild Thrombocytopenia after ChAdOx1 nCoV-19 Vaccination
This study reports two cases of vaccine-induced immune thrombotic thrombocytopenia (VITT) presenting with mild thrombocytopenia and venous thromboembolism following ChAdOx1 nCoV-19 vaccination, highlighting the spectrum of VITT severity and the importance of recognizing delayed …
DOI: 10.1055/a-1585-6182 -
Complicated Long Term Vaccine Induced Thrombotic Immune Thrombocytopenia—A Case Report
This case report details the complicated long-term course of a patient with vaccine-induced thrombotic thrombocytopenia (VITT) following COVID-19 vaccination, highlighting persistent high titers of anti-platelet factor 4 antibodies and recurrent thrombocytopenia despite treatmen…
DOI: 10.3390/vaccines9111344 -
Adaptation of ISTH Guidelines on Vaccine Induced Thrombocytopenic Thrombosis to Clinical Practice and Analysis of Patient Cases
Ten AstraZeneca vaccine-associated VITT cases were analyzed against ISTH guidelines, revealing universal PF4 positivity and significant abnormalities in platelets and D-Dimer, with IVIG and non-heparin anticoagulants used, supporting practical adaptation of ISTH guidance in clin…
DOI: 10.23880/hij-16000197 -
Thrombosis with thrombocytopenia after first dose of ChAdOx1 nCoV-19 vaccine: a case report
Cerebral venous sinus thrombosis with severe thrombocytopenia (VITT) occurred after the first dose of ChAdOx1 nCoV-19 vaccine, was diagnosed via anti-PF4 antibodies, and was managed with IVIG, steroids, non-heparin anticoagulation (apixaban), platelet-sparing strategies, and dec…
DOI: 10.29014/ns.2021.32 -
Comparison of vaccine-induced immune thrombocytopenia and thrombosis cases following two adenovirus-vectored COVID-19 vaccines
A descriptive comparison of 86 Ad26.COV2.S and 220 ChAdOx1 nCoV-19 VITT cases found no strong evidence of a clinically relevant difference in patient characteristics or outcomes, with observed differences attributed to vaccination demographics and reporting or detection differen…
DOI: 10.1038/s43856-025-00891-x -
Arterial intracranial thrombosis as the first manifestation of vaccine-induced immune thrombotic thrombocytopenia (VITT): a case report
This case report describes a severe instance of vaccine-induced immune thrombotic thrombocytopenia (VITT) leading to massive ischemic stroke in a 42-year-old woman following her first dose of the ChAdOx1 nCoV-19 vaccine.
DOI: 10.1007/s10072-021-05800-3 -
A Case Report of Thrombotic Thrombocytopenia After ChAdOx1 nCov-19 Vaccination and Heparin Use During Hemodialysis
This case report describes a 70-year-old male who developed thrombotic thrombocytopenia after receiving the ChAdOx1 COVID-19 vaccine and undergoing hemodialysis with heparin, highlighting the challenges in distinguishing between vaccine-induced immune thrombotic thrombocytopenia…
DOI: 10.3346/jkms.2022.37.e75 -
Portal Vein Thrombosis due to Vaccine-Induced Immune Thrombotic Thrombocytopenia (VITT) after Covid Vaccination with ChAdOx1 nCoV-19
This case report describes a 29-year-old male who developed portal vein thrombosis due to vaccine-induced immune thrombotic thrombocytopenia (VITT) following vaccination with the AstraZeneca COVID-19 vaccine, highlighting the importance of early diagnosis and treatment.
DOI: 10.1055/a-1579-9303 -
Immediate high-dose intravenous immunoglobulins followed by direct thrombin-inhibitor treatment is crucial for survival in Sars-Covid-19-adenoviral vector vaccine-induced immune thrombotic thrombocytopenia VITT with cerebral sinus venous and portal vein thrombosis
This case report describes a 29-year-old male who developed vaccine-induced immune thrombotic thrombocytopenia (VITT) after receiving the AstraZeneca COVID-19 vaccine, highlighting the critical role of immediate high-dose intravenous immunoglobulins and direct thrombin inhibitor…
DOI: 10.1007/s00415-021-10599-2 -
SARS-CoV-2 Vaccine-Induced Immune Thrombotic Thrombocytopenia with Venous Thrombosis, Pulmonary Embolism, and Adrenal Haemorrhage: A Case Report with Literature Review
This case report describes a 39-year-old patient who developed vaccine-induced immune thrombotic thrombocytopenia (VITT) with severe complications including venous thrombosis, pulmonary embolism, and adrenal hemorrhage following vaccination with the Johnson & Johnson COVID-19 va…
DOI: 10.3390/vaccines10040595 -
COVID-19 vaccination–related cardiovascular complications
This narrative review finds COVID-19 vaccination is associated with rare cardiovascular complications, especially mRNA vaccine myocarditis in young men and adenoviral vaccine VITT/VTE, but myocarditis and thrombosis are more common after SARS-CoV-2 infection and benefits outweig…
DOI: 10.36011/cpp.2023.5.e17