Log in to MyACC
AZD1222 and BNT162b2 Vaccines and VITT in Frontline Personnel
Quick Takes
- Receipt of AZD1222 COVID-19 vaccination was associated with a small increased risk of deep vein thrombosis among frontline healthcare workers.
- Receipt of AZD1222 COVID-19 vaccination had a small numerically (but not statistically) increased risk of cerebral sinus vein thrombosis and thrombocytopenia.
- Receipt of BNT162b2 COVID-19 vaccination was not associated with thromboembolic events or thrombocytopenia among frontline healthcare workers.
Study Questions:
What is the risk of thrombosis and thrombocytopenia syndrome (TTS; also known as vaccine-induced thrombotic thrombocytopenia, VITT) following AZD1222 (Oxford-AstraZeneca) or BNT162b2 (Pfizer-BioNTech) coronavirus disease 2019 (COVID-19) vaccination?
Methods:
The authors identified 255,209 Danish frontline personnel who received COVID-19 vaccination between December 2020–April 2021. Using Danish linkable registers on vaccination, hospitalizations, occupation, and other covariates, they identified study outcomes of cerebral venous sinus thrombosis, splanchnic vein thrombosis, pulmonary embolism, deep vein thrombosis, arterial thrombosis, thrombocytopenia, and death. The cumulative incidence of the study outcomes was calculated within 28 days of vaccination and compared to unvaccinated time periods using adjusted survival curves.
Results:
Among 355,209 Danish frontline personnel, vaccination with AZD1222 versus no vaccination was associated with a significant risk difference at day 28 for deep vein thrombosis (8.35 per 100,000 vaccinations; 95% confidence interval, 0.21-16.49) but no significant risk difference for cerebral venous sinus thrombosis or thrombocytopenia. There were no significant associations seen for BNT162b2 vaccination and the study outcomes.
Conclusions:
The authors concluded that receipt of the AZD1222 vaccine was associated with a small excess risk for deep vein thrombosis. The authors also concluded that there was no statistically significant increased risk of thromboembolic events or thrombocytopenia within 28 days following BNT162b2 vaccination.
Perspective:
Since March 2021, there has been significant concern about the risk of unusual site thrombosis events associated with thrombocytopenia following the AZD1222 COVID-19 vaccine. Any association between thrombotic events and mRNA vaccination, including BNT162b2 COVID-19 vaccination remains to be assessed. This study of >350,000 Danish frontline healthcare personnel highlight that there is a small but measurable association between AZD1222 vaccine receipt and deep vein thrombosis risk. However, the study was unable to identify a specific risk with thrombocytopenia or unusual site thrombosis (e.g., cerebral sinus vein, splanchnic vein). This may be due to the very low (if any) increased risk of these rare events following AZD1222 vaccine receipt. In this study, both has numerically increased risk that did not achieve statistical significance, perhaps due to a limited sample size. Importantly, no thromboembolic risks were identified following BNT162b2 vaccine receipt. This study highlights the general safety of both the AZD1222 and BNT162b2 vaccines in regard to potential thromboembolic event risk and should be widely recommended to reduce the morbidity and mortality associated with COVID-19 infection.
Clinical Topics: Cardiovascular Care Team, COVID-19 Hub, Prevention, Vascular Medicine
Keywords: Allied Health Personnel, COVID-19, COVID-19 Vaccines, Embolism and Thrombosis, Mass Vaccination, Pulmonary Embolism, RNA, Messenger, Secondary Prevention, Thrombocytopenia, Thrombosis, Vaccination, Vascular Diseases, Venous Thrombosis
< Back to Listings
