Clinical outcomes of COVID-19 in patients with sickle cell disease and sickle cell trait: A critical appraisal of the literature

• Published in: Blood reviews Vol. 53; p. 100911
• Main Authors: Hoogenboom, Wouter S., Alamuri, Tharun T., McMahon, Daniel M., Balanchivadze, Nino, Dabak, Vrushali, Mitchell, William B., Morrone, Kerry B., Manwani, Deepa, Duong, Tim Q.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.05.2022
• Subjects: Adult; Anemia, Sickle Cell - drug therapy; Anemia, Sickle Cell - therapy; Child; COVID-19; COVID-19 - therapy; Hemoglobinopathies; Humans; Hydroxyurea - adverse effects; Red blood cell disorder; Review; SARS-CoV-2; Sickle cell disease; Sickle cell trait; Sickle Cell Trait - chemically induced; Sickle Cell Trait - complications; Sickle Cell Trait - drug therapy; COVID-19; Sickle cell trait; SARS-CoV-2; Hemoglobinopathies; Red blood cell disorder; Sickle cell disease
• ISSN: 0268-960X; 1532-1681
• DOI: 10.1016/j.blre.2021.100911

Individuals with sickle cell disease (SCD) and sickle cell trait (SCT) have many risk factors that could make them more susceptible to COVID-19 critical illness and death compared to the general population. With a growing body of literature in this field, a comprehensive review is needed. We reviewed 71 COVID-19-related studies conducted in 15 countries and published between January 1, 2020, and October 15, 2021, including a combined total of over 2000 patients with SCD and nearly 2000 patients with SCT. Adults with SCD typically have a mild to moderate COVID-19 disease course, but also a 2- to 7-fold increased risk of COVID-19-related hospitalization and a 1.2-fold increased risk of COVID-19-related death as compared to adults without SCD, but not compared to controls with similar comorbidities and end-organ damage. There is some evidence that persons with SCT have increased risk of COVID-19-related hospitalization and death although more studies with risk-stratification and properly matched controls are needed to confirm these findings. While the literature suggests that most children with SCD and COVID-19 have mild disease and low risk of death, some children with SCD, especially those with SCD-related comorbidities, are more likely to be hospitalized and require escalated care than children without SCD. However, children with SCD are less likely to experience COVID-19-related severe illness and death compared to adults with or without SCD. SCD-directed therapies such as transfusion and hydroxyurea may be associated with better COVID-19 outcomes, but prospective studies are needed for confirmation. While some studies have reported favorable short-term outcomes for COVID-19 patients with SCD and SCT, the long-term effects of SARS-CoV-2 infection are unknown and may affect individuals with SCD and SCT differently from the general population. Important focus areas for future research should include multi-center studies with larger sample sizes, assessment of hemoglobin genotype and SCD-modifying therapies on COVID-19 outcomes, inclusion of case-matched controls that account for the unique sample characteristics of SCD and SCT populations, and longitudinal assessment of post-COVID-19 symptoms.