Introduction
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel
virus first detected in Wuhan in December 2019. Few months later, the
World Health Organization (WHO) declared a worldwide pandemic. This
virus may cause severe viral pneumonia with acute respiratory distress
syndrome causing millions of deaths.1,2 Currently,
there is no effective treatment for
coronavirus disease 2019
(COVID-19).3 However, several vaccines have been
developed worldwide to reduce COVID-19 mortality and
morbidity.4 Those vaccines have obtained emergency use
approval by the WHO in several countries increasing the risk of vaccine
safety issues and some adverse events have been
reported.5–7 Most frequent were
injection site reactions or
systemic effects (eg, fatigue, headache, body pain, fever), with rare
serious adverse events (eg,
anaphylaxis, Guillain-Barré, thrombosis with thrombocytopenia
Syndrome).8–10 Several cases of Thrombotic
Thrombocytopenic Purpura (TTP)
induced by COVID-19 vaccination
have been reported in the literature.11–14 TTP is a
rare hematologic disorder classically characterized by the pentad of
fever, hemolytic anemia, thrombocytopenia, renal failure, and neurologic
dysfunction. However, most patients do not have the entire
pentad.15 This disease is caused by a severe decrease
in the activity of the von Willebrand factor-cleaving protease ADAMTS-13
which can be either congenital or acquired due to anti-ADAMTS-13
autoantibodies.11 Various events may initiate the
production of those antibodies such viral infections, medication,
pregnancy, malignancies and occasionally
vaccinations.16 Here, we report two cases of acquired
TTP after two inactivated COVID-19 vaccines: BBIBP-CorV vaccine known as
the Sinopharm COVID-19 vaccine and CoronaVac known as the Sinovac
vaccine. To the best of our knowledge, the present cases are the first
reported cases of acquired TTP after inactivated virus COVID-19
vaccines.