UCSF

The coronavirus disease 2019 (COVID-19) pandemic remains one of the largest global health crises of the last century. Fortunately, COVID-19 vaccines have proven to be one of the most promising options in halting the progression of the pandemic. As more and more people receive COVID-19 vaccines, the medical community has learned a great deal about their efficacy and the occurrence of very rare adverse effects. While the number of thromboembolic events post-adenoviral vaccines has been well-documented in the medical literature, there has been limited information regarding thrombosis development after receiving a messenger RNA (mRNA)-based vaccine. This case series highlights four different patients who received an mRNA-based COVID-19 vaccine and subsequently developed venous thromboembolism. Therefore, we hope that after reviewing this article, physicians will be more aware of thrombosis-related developments following mRNA vaccine administration for COVID-19. Fortunately, with early diagnosis and prompt treatment, patients can still expect full recovery from any vaccine thrombosis-associated complications, and the benefits of receiving an mRNA-based COVID-19 vaccine still outweigh the risks of post-vaccination complications.