COVID-19 omicron variant outbreak in a hematopoietic stem cell transplant unit

Abstract

Recommendations and guidelines for management of SARS-COV-2 infection in hematologic patients were developed in the very difficult context of dealing with novel viral variants from one pandemic wave to another, with different susceptibility to available drugs and vaccines. Moreover, the largest SARS-COV-2 case series in patients treated for hematologic malignancies, including stem cell transplant recipients, was published before the Omicron surge, and refers mainly to Alpha and Delta viral variants. These infections had very high mortality, in a period when antivirals and monoclonal antibodies were mostly unavailable. Here, we report for the first time a SARS-COV-2 Omicron variant outbreak inside a Bone Marrow Transplant (BMT) Unit, describing the characteristics, clinical course, and infection outcomes shortly before and shortly after myeloablative transplantation. We detail how infections were treated off-label and managed inside the BMT ward, to guarantee the best possible outcomes while avoiding risks for non-infected inpatients. The positive outcomes observed suggest that it may not be absolutely necessary to obtain SARS-CoV-2 PCR negativity before BMT in hematologic patients after treated infection, in cases with long-term PCR positivity and high-risk hematologic disease.

Keywords: COVID-19; SARS-CoV-2; Stem cell transplant.

Fig. 1

Transplant timeline of patient 1. The x axis represents days before and after transplant, stem cell infusion is on day “0”. In the upper part: white blood cell count (WBC/ul, blue line) and SARS-CoV-2 IgG title (dark orange line), with temporal representation in days or interval of administration of granulocyte-colony stimulating factor (GCSF) and anti-HSV1 and anti-CMV therapies (acyclovir high dose: 10 mg/kg/8 h; ganciclovir: 5 mg/kg/12 h; foscarnet: 90 mg/kg/12 h). In the lower part: SARS-CoV-2 PCR amplification cycles on nasal swab (light orange line), SARS-CoV-2 RNAemia on peripheral blood and CD4 + T cells counts (cells/ul, green line), with temporal representation in days or interval of administration of conditioning therapy, GVHD prophylaxis, antiviral, and monoclonal antibodies used to treat SARS-CoV-2. TBI: total body irradiation (1200 cGy total dose, 200 cGy/fraction). Cy: cyclophosphamide 60 mg/kg/d for 2 days. ATG: anti-T-lymphocyte globulin “Grafalon”, 40 mg/kg total dose. MTX 10-10-10-10: methotrexate 10 mg/sm (days 1, 3, 6, 11). BAU: binding antibody unit