Acquired aplastic anemia following SARS-CoV-2 vaccination.

COVID-19 is a potential life-threatening viral disease caused by SARS-CoV-2 and was declared a pandemic by the WHO in March 2020. mRNA-based SARS-CoV-2 vaccines are routinely recommended in immune-compromised patients, including patients with AA, as these patients are at increased risk of contracting COVID-19 and developing a more severe course of disease. Between March 2021 and November 2021 relapse of AA occurred in four (age [median]: 53 years, range 30-84 years) out of 135 patients currently registered at our department and two de novo cases of AA in temporal context to vaccination against SARS-CoV-2, were documented. Median time after first COVID-19 vaccination and relapse of AA was 77 days. All relapsed patients were vaccinated with the mRNA-based vaccine Comirnaty®. Relapse in two out of the four patients was refractory to CsA/eltrombopag, favoring IST with hATG/CsA or BMT, respectively. Our observations should prompt clinicians to take vaccine-induced relapse of AA or de novo AA after SARS-CoV-2 vaccination into account. Furthermore, careful clinical monitoring and vigilance for signs or symptoms that may indicate relapse of AA (e.g., bleeding complications) are indicated.