Thalassemia and COVID-19: Susceptibility and Severity

Abstract

Context: COVID-19 results in an imbalance between procoagulant and anticoagulant homeostatic mechanisms that could be complicated with thrombotic events. In β-thalassemia patients, the presence of comorbidities, iron overload, adrenal hypofunction, splenectomy, and chronic hypercoagulable state might increase the susceptibility to COVID-19 and its severity. Evidence Acquisition: The search was conducted in PubMed, Web of Science, and Scopus databases for the key terms of β-thalassemia/thalassemia and COVID-19 until July 2021. Results: The survey of published observational studies (mostly multicenter and case reports) indicated a lower prevalence of COVID-19 in β-thalassemia patients compared with the general population, as well as mild to moderate COVID-19 in these patients, especially in those without comorbidity. β-Thalassemia children were susceptible to COVID-19 but with less severity compared to adults. There is no report of pulmonary embolism and thrombotic events in β-thalassemia patients with COVID-19; however, coagulation abnormality and pulmonary microembolism have been found in these patients. Conclusions: Findings could be interpreted by the presence of high hemoglobin F (HbF) levels, the advantage of hydroxyurea (HU) therapy, splenectomy, and iron chelation therapy in these patients. However, due to the low sample size and studying mainly young patients, the results should be interpreted with caution, and it still needs more studies with a larger sample size to confirm these findings.

Comparing serum ferritin levels during COVID-19 infection and recovery period in pediatric patients with transfusion-dependent thalassemia, a single-center study

“…Several studies showed that the susceptibility to severe disease and mortality were more profound in non-TDT patients ( 7 , 8 , 20 ). Thus, patients with TDT were associated with less severe disease and improved outcomes ( 27 ). These patients regularly received blood transfusions which could decrease the occurrence of anemia-related complications and compensation for bone marrow expansion.…”

“…These patients regularly received blood transfusions which could decrease the occurrence of anemia-related complications and compensation for bone marrow expansion. Iron chelation therapy also reduces iron overload related to multiple transfusions ( 27 ). Severe diseases of COVID-19 in TDT patients are shown to be due to the coexistence of organ damage associated with iron overload including cardiomyopathy and heart failure ( 5 , 28 ).…”

“…During SAR-CoV-2 infection, the beta chain of Hb was attacked, resulting separation of iron from the porphyrin ring, and impairing the oxygen transfer process. It could be that the viral protein competes with iron to bind to this porphyrin ring, interfering the normal heme anabolic pathway ( 27 , 29 ). A study had suggested that some proteins of this coronavirus attacked the heme on the beta chain of hemoglobin, both oxygenated and deoxygenated hemoglobin.…”