28,198 healthcare staff exposed to PfizerBioNTech/Moderna (N = 11,689) or Oxford-AstraZeneca (N = 16,509) COVID-19 vaccines.

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50 (40 women and 10 men) had thrombocytopenia of 2,130 with post-vaccination platelets measured.

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Among 1,873 women, 3.0% exposed to Oxford-AstraZeneca versus 1.5% to PfizerBioNTech/Moderna had thrombocytopenia.

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This corresponds to an OR of 1.99 [95% CI 1.05–3.76]; among 257 men, the corresponding OR [95% CI] was 0.49 [0.14–1.79].

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Severe thrombocytopenia (platelets <50 × 109/L) was seen among Oxford-AstraZeneca-exposed patients only (3 women age 50–60).