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COVID-19 Resources

COVID-19 and Sickle Cell Disease: Frequently Asked Questions

(Version 6.1; last updated May 28, 2021)

Input from Arun Shet, MD, PhD; Ken Ataga, MD; Ted Wun, MD; Matthew Hseih, MD; Allison King, MD, MPH, PhD; Rakhi Naik, MD; Alexis Thompson, MD; and Michael DeBaun, MD.

Note: Please review ASH's disclaimer regarding the use of the following information.

How do people with sickle cell disease (SCD) do with COVID-19?

Patients with SCD often have underlying cardiopulmonary co-morbidities that may predispose them to poor outcomes if they become infected with SARS-CoV-2.

A large study of electronic health record data identified 312 patients with COVID-19 and SCD between January 20, 2020, to September 20, 2020.1 After propensity score matching, patients with COVID-19 and SCD remained at a higher risk of hospitalization (relative risk [RR], 2.0; 95% CI, 1.5-2.7), development of pneumonia (RR, 2.4; 95% CI, 1.6-3.4), and pain (RR, 3.4; 95% CI, 2.5-4.8) compared with Black individuals without SCD. Case fatality rates for SCD patients were not significantly different from those of Black individuals without SCD.

A smaller study from four major metropolitan cities in the United States identified indivduals with SCD with the following risk factors for higher incidence of death from COVID-19: pre-existing cardiopulmonary illness, renal disease, and/or stroke; not receiving hydroxyurea; presenting with high serum creatinine, lactate dehydrogenase, and/or D-dimer levels.2

SCD patients infected with SARS-CoV-2 should be followed very closely, applying a low threshold for admission and frequent outpatient check-ins via telemedicine or in person as appropriate, particularly following hospital discharge.

The Sickle Cell Disease Association of America updates its recommendations frequently about best practices for the care of SCD patients in the era of COVID-19. Below, we address FAQs that arise most commonly from providers less familiar with SCD.

How should I evaluate respiratory symptoms in children and adults with an active COVID-19 infection?

There is significant overlap in presenting symptoms between COVID-19, acute chest syndrome (ACS) and other infectious causes of pneumonia. Providers should test for COVID-19 and other infectious pathogens and have a low threshold for imaging. COVID-19 most commonly presents with a more diffuse ground glass appearance, versus more localized infiltrates consistent with consolidation. These findings are not always distinct, and all possibilities should remain in the differential. A detailed checklist for evaluating SCD patients with these symptoms in the emergency department has been developed by ASH in collaboration with ED physicians.

Often transfusion therapy is the only effective intervention for respiratory failure due to ACS, with a goal to reduce the hemoglobin S (HbS) level to approximately 15% via exchange transfusion, in order to ensure that HbS levels remain less than 30% for approximately 4 weeks. Whether reducing HbS via transfusion improves outcome in COVID-19 respiratory failure is unknown, but decreased sickling in this setting as in ACS would seem desirable. Whether reduction of HbS to < 15% should be pursued will be based on the patient's clinical acuity, availability of appropriate red blood cell units, and feasibility of RBC exchange apheresis at the local facility. Fllowing automated exchange transfusion, a hemoglobin between 10 and 12g/dL should be targeted to maximize oxygen carrying capacity.

Transfer to another facility should be strongly considered early after presentation if automated exchange transfusion therapy cannot be performed. Simple transfusion can be given in the interim, with avoidance of hyperviscosity by targeting a post transfusion Hb of less than 10g/dL.

Should I change my use of exchange transfusion for neurological acute symptoms suggesting a stroke or transient ischemic attack?

For acute stroke or transient ischemic attack (TIA) occurring during the pandemic, we recommend reducing the percent HbS level to approximately 15% via exchange transfusion. This strategy provides sustained HbS levels less than 30% for approximately 4 weeks, and is consistent with the ASH CNS guidelines recommendations for management of acute strokes and TIAs. Early reduction in HbS has been associated with better outcomes after stroke. Simple transfusion can be given while preparing for exchange transfusion, with avoidance of hyperviscosity by targeting a post infusion Hb less than 10g/dL.

Should I change my use of exchange transfusion or regular blood transfusion for primary and secondary stroke prevention, secondary prevention of ACS, pain or priapism?

If there is no blood supply shortage, there should be no change in the use of exchange transfusion or regular blood transfusions for primary and secondary stroke prevention or prevention of ACS, pain, or priapism in individual SCD patients.

If a blood supply shortage occurs again or has not abated in selected areas, and if the patient requires regular blood transfusion therapy for prevention of organ damage, we would consider starting low-dose hydroxyurea (10 mg/kg/day). Low-dose hydroxyurea is started in the event that the patient may have to skip a scheduled blood transfusion for primary or secondary stroke prevention. For prevention of ACS, pain, or priapism, hydroxyurea, crizanlizumab, or both can be used. In addition, there should be consideration of L-glutamine with or without hydroxyurea.

My patient usually receives antigen-matched red cells. Should I use non-matched units if there is a blood shortage?

If possible, continue to transfuse antigen-matched units to prevent alloimmunization, unless blood transfusion is life-saving and time sensitive and matched units are not immediately available. For patients with a history of delayed hemolytic transfusions, at a minimum the minor red cell antigens should be matched for Rh (C, E or C/c, E/e), and K, and should lack any antigens identified in the DHTR evaluation. Additional matching should be considered for Jka/Jkb, Fya/Fyb, and S/s. A conversation with the local or regional blood bank personnel should occur to optimize the best potentially matched units. Immunosuppressive therapy should be considered on a case-by-case basis for DHTR. In patients with a history of hyperhemolysis, prophylactic immunosuppressive therapy is advised. For more information on transfusion management see the ASH transfusion guidelines in SCD.

How should one balance risk of hospitalization for acute painful vaso-occlusive episode management vs. risk of exposure to COVID-19?

Where possible, consider telemedicine patient contact and optimize the use of oral opioids. To limit exposure to COVID-19, shift as many patients as feasible to receive intravenous narcotics in a day hospital, if available, rather than the emergency department. Minimizing provider cross coverage between outpatient/day hospital and inpatient units is desirable. However, in countries with high vaccination rates or low case prevalence and a medical system that is not overwhelmed, we would encourage in-person medical visits for assessment and laboratory studies.

Should a child or adult with severe COVID-19 infection receive therapeutic anticoagulation?

Hospitalized patients should receive prophylactic doses per institutional practice unless there is an indication for full anticoagulation. Therapeutic or higher than prophylactic dosing of anticoagulation should only be administered in the context of a clinical trial. For additional details please see the COVID-19 VTE/anticoagulation FAQs. To date, no prospective studies have specifically addressed the impact of anticoagulation in patients with SCD and COVID-19 infection.

Should children or adults with SCD and COVID-19 receive COVID-19 disease-ameliorating therapies?

In critically ill SCD patients with hypoxic respiratory failure due to COVID-19, the use of dexamethasone in addition to other routine treatments may limit severe lung injury. Rebound steroid-induced VOC can be managed symptomatically, should it occur.

For non-critically ill SCD patients with COVID-19 infection, dexamethasone can limit progression to severe disease. Baricitinib with remdesivir may have a role in patients who cannot receive dexamethasone. Monoclonal monoclonal antibody treatments (bamlanivimab and the combination casirivimab/imdevimab) or convalescent plasma under FDA emergency use authorizations may reduce the risk of hospitalization for COVID-19 patients at high risk of complications and mortality, but must be administered within several days of symptom onset, before progression to moderate to severe symptoms or hospitalization for benefit based on trials reported to date. Trials focused specifically on these therapies in SCD patients have not been reported, but consideration of these therapies to limit progression to more serious complications of COVID-19 appear warranted in SCD patients, given their very high risk of severe disease.

Is there any specific guidance you are giving patients that are considering stem cell transplantation or gene therapy for SCD?

Many programs have resumed nonemergent such as allogeneic transplantation and gene therapies for SCD, but the situation varies greatly by local pandemic status. Individuals should contact their primary hematologist or transplant center for updates. Patients and donors should be fully vaccinated prior to initiation of conditioning regimens.

Should I adjust doses of any SCD medications given the COVID-19 threat?

If a patient is doing well, there is no reason to change any SCD medications because of the COVID-19 pandemic or actual infection, including recently approved medications such as volexotor and crizanlizumab.

For patients with symptomatic baseline low hemoglobin levels or patients that are difficult to transfuse because of alloantibodies, voxelotor, a therapy designed to increase the baseline hemoglobin level, can be considered. The decision to begin this agent should be based on the relative benefits versus the risks.

If COVID-19 rates remain high in your area, to reduce frequency of clinic and pharmacy visits consider telemedicine visits and increasing the supply of medication to 90 days as allowed.

Should approved COVID-19 vaccines be administered to SCD patients?

The Centers for Disease Control and Prevention (CDC) has designated SCD among the medical conditions with high risk for severe COVID-19. The Advisory Committee on Immunization Practice (ACIP) recommends that SCD patients older than age 16 years be vaccinated. The FDA recently extended emergency use authorization for the Pfizer-BioNTech COVID-19 vaccine to include adolescents 12 through 15 years of age. Given the high levels of efficacy for vaccines and the low rates of vaccine-related adverse reactions, hematologists should encourage patients with SCD to receive COVID-19 vaccines. Trials studying vaccine efficacy rates in patients with SCD are ongoing. Based on experience with other vaccines, such as the flu vaccines, patients would be expected to respond to COVID-19 vaccines, but potentially with lower antibody titers and/or a shorter period of protection. Trusted providers can play key roles in overcoming vaccine hesitancy, particularly in vulnerable populations. For more information, see the ASH FAQ on COVID-19 vaccination in immunodeficient hematology patients.

If vaccination with the ChAdOx1 nCov-19 (AstraZeneca) or Johnson & Johnson vaccine is considered, clinicians should be aware of the potential for development of venous or arterial thrombosis accompanied by thrombocytopenia 4 to 30 days after vaccination.


  1. Singh et al, Blood Advances, 2021. 10.1182/bloodadvances.2020003741
  2. Minitti et al, Clinical predictors of poor outcomes in patients with sickle cell disease and COVID-19 infection. Blood Advances, 2021. 10.1182/bloodadvances.2020003456
  3. De Baun, M. Initiating adjunct low dose-hydroxyurea therapy for stroke prevention in children with SCA during the C0VID-19 pandemic. In press, Blood 2020.

For additional information, see:

View All COVID-19 FAQs