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COVID-19 Resources

COVID-19 and Sickle Cell Disease: Frequently Asked Questions

(Version 3.0; last updated May 1, 2020)

Input from Drs. Arun Shet, Ken Ataga, Ted Wun, Matthew Hseih, Allison King, Rakhi Naik, Alexis Thompson, Michael DeBaun

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. Data are being collected by the international COVID-19 sickle cell disease registry and by the ASH Registry, and providers are encouraged to report their SCD patients with COVID-19.

The Sickle Cell Disease Association of America updates its recommendations weekly 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 pneumonia or ACS. These findings are not always distinct and all possibilities should remain in the differential. Often automated exchange transfusion is the only effective therapy for respiratory failure due to ACS, and transfer to another facility with this capability may be required. Simple transfusion can be given in the interim, with avoidance of hyperviscosity. Whether reducing HbS via transfusion improves outcome in COVID-19 respiratory failure is unknown, but decreased sickling in this setting as in ACS is desirable.

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

For acute stroke presentation or transient ischemic attack (TIA), we recommend dropping the percent hemoglobin S level to approximately 15% via exchange transfusion. This strategy provides sustained hemoglobin S levels less than 30% for approximately 4 weeks and is consistent with the ASH CNS guidelines recommendations for management of acute strokes and TIAs.

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?

At present, transfusion practices in children and adults with SCD are being modified on a case by case basis as determined by individual physicians and practice groups. Some providers are electing to relax exchange transfusion endpoints (i.e. allowing 40% HbS) or switching to simple exchange transfusion (for an interim period) to minimize unit consumption.

In areas where severe blood shortages are expected, some providers are initiating hydroxyurea in patients on routine blood transfusions because the transition to maximum tolerated dose of hydroxyurea may require up to 6 months to be fully effective. Based on efficacy of hydroxyurea for primary and secondary stroke prevention when compared to no red blood cell transfusion, after discussion with the family and the local blood bank personnel, we would consider starting low dose hydroxyurea in children with an indication for primary or secondary stroke prevention, if blood transfusion services are likely to be interrupted1 Randomized controlled trial data are not available, but a similar strategy for secondary prevention of stroke is plausible for adults.

The evidence for transfusion and secondary prevention of ACS, pain and priapism has not been evaluated in a randomized controlled trial, but rather as secondary analyses from stroke prevention randomized controlled trials. Collectively, these data, along with extensive clinical experience, suggest regular blood transfusion does decrease the incidence rate of acute chest syndrome, acute pain episodes and priapism events, and thus transfusion therapy should be continued on an individualized basis if possible for these indications.

Should we alter approaches to transfusion triggers and blood use in children and adults with SCD?

In anticipation of blood shortages, the transfusion trigger for common clinical situations i.e., severe anemia, VOC, priapism, etc. may need adjustment. In some institutions, the decision to suspend elective surgeries may explain why these shortages have not occurred. Transfusions should be given for symptoms arising from severe anemia or acute complications (e.g. ACS or stroke) and not based solely on preestablished hemoglobin thresholds.

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

To reduce exposure to COVID-19 patients, shift as many patients as feasible to receive intravenous narcotics in the day hospital (if day hospital is available and has implemented appropriate distancing and isolation practices) rather than the emergency department. Minimizing the provider cross coverage between outpatient/day hospital and inpatient units is desirable. Where possible, consider telemedicine patient contact and optimize use of oral opioids.

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

No, they should receive only prophylactic doses, or “intermediate intensity” dosing (0.5mg/kg enoxaparin twice daily) per institutional ICU practice or as part of a clinical trial, unless there is an indication for full anticoagulation.2 For additional details, please see the COVID-19 VTE/anticoagulation FAQs.

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

Most transplant and gene therapy programs are deferring non-emergent treatments including transplantation and gene therapy.

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

If possible and consistent with good medical practice, maintain the goal of using antigen-matched units to prevent alloimmunization unless blood transfusion is life-saving. In patients with a history of delayed hemolytic transfusion reaction, prophylactic immunosuppressive therapy is advised. For additional information, see the ASH transfusion guidelines in SCD.

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 threat or if they become infected. To decrease clinic and pharmacy visits, consider increasing the supply of medication to 90 days as allowed, with telemedicine check-ins.

What is the role of recently approved disease-modifying drugs, voxelotor and crizanlizumab, during the COVID-19 pandemic?

Patients on these medications should be continued. If not yet started, and in light of orders to shelter in place in many locations and minimize non-essential movement and medical visits, consider delaying new drug initiation.

For patients with symptomatic baseline low hemoglobin levels or patients that are difficult to transfuse because of alloantibodies, volextotor, 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 and likelihood of impending decreased blood supply.


  1. 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.
  2. Connors, J and Levy, J. COVID-19 and its implications for thrombosis and anticoagulation. Blood 2020.

For additional information, see:

View All COVID-19 FAQs

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