Risk of venous thromboembolism after SARS‐CoV‐2 vaccination—Evidence from genome‐wide association study and population‐based observational study

AIM: We aimed to investigate whether genetic variation is associated with venous thromboembolism after immunization with SARS-CoV-2 vaccines. METHODS: We conducted a genome-wide association study (GWAS) on cases of venous thromboembolism within 42 days after SARS-CoV-2 vaccination, recruited from reports of adverse drug reactions sent to the Swedish Medical Products Agency. Two hundred one cases (43% women, 91% Swedish) were compared with 4891 Swedish population controls. Analyses were performed on two candidate variants in coagulation factor II (rs1799963) and coagulation factor V (rs6025), on 14 prespecified candidate genes and across the whole genome. To support the findings, we conducted an observational register study of the Swedish general population with/without a diagnosis of thrombophilia and the risks of venous thromboembolism after SARS-CoV-2 vaccination. RESULTS: In the GWAS, the main findings were that the candidate variants of coagulation factors II rs1799963 and V rs6025 were significantly associated with venous thromboembolism (odds ratio [OR] 2.4 [95% confidence interval (CI) 1.2-4.8], p = .015 and OR 1.8 [95% CI 1.3-2.6], p = .0022). No genetic marker passed the significance threshold in the candidate gene analysis or the full genome-wide analysis. In the register study, people with a thrombophilia diagnosis had a five-fold elevated risk of venous thromboembolism within 42 days after vaccination, adjusted for potential confounders, OR 5.06 [95% CI 3.98-6.44]. CONCLUSION: Well-characterized genetic variants in the genes of coagulation factors II and V were associated with thromboembolism after SARS-CoV-2 immunization. Further research is recommended to elucidate their potential role in vaccine-related thromboembolic events.