Use of Convalescent Plasma Therapy in Severe Coronavirus Disease 2019: The Yale-New Haven Health System Experience

Background: Coronavirus disease 2019 (COVID-19), a multi-system disorder resulting from infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has affected 5.0 million individuals in the United States (US) resulting in more than 160,000 deaths. There is currently no proven effective therapy for SARS-CoV-2 infection beyond supportive care. Convalescent plasma (CP), collected from individuals who have recovered from SARS-CoV-2 infection, has been safely used to transfer virus-neutralizing antibodies to patients hospitalized with COVID-19. Herein we report on the clinical course and outcomes of patients who received CP for the treatment of COVID-19 across our health system.Methods: Hospitalized patients ≥ 18 years of age at 5 hospitals in the Yale-New Haven Health System with confirmed SARS-CoV-2 infection and severe or life-threatening disease (Figure 1) were enrolled in the US COVID-19 Expanded Access Program (EAP) and transfused 1 unit of CP. Patient outcomes were assessed at 7, 14, and 28 days after CP transfusion. Furthermore, we sought to determine mortality predictors in this patient cohort.Results: 105 patients enrolled in the EAP were transfused CP from 4/12/2020 to 6/14/2020. Median age was 62 years (28-88 years). 62.9% of patients were male. Individuals of a non-white race comprised 56.2% of our cohort and 33.3% identified as Hispanic or Latinx. 47.6% of patients had a body mass index greater than 30, with 13.3% classified as extremely obese. Diabetes mellitus, hypertension, and hyperlipidemia were highly prevalent in our population. Concomitant therapy for COVID-19 included hydroxychloroquine (79.0%), tocilizumab (79.0%), and remdesivir (23.8%) (Table 1). 91 patients required the intensive care unit (ICU) during their hospital course, with 87 patients in the ICU at the time of CP transfusion. 42.9% of patients had an improvement in their World Health Organization (WHO) Ordinal Scale score by day 7 post-CP transfusion (median 4 days to improvement), while 9.5% demonstrated an increase in their WHO score indicating worsening oxygenation during the 7 days following CP (Figure 2). Mortality was 10.48% at 7 days, 20.95% at 14 days, and 28.57% at 28 days post-CP transfusion (Figure 2). Of the patients in the ICU at the time of CP, 56 (64.4%) de-escalated to non-ICU care after a median of 8 days from transfusion and 55 (63.2%) were ultimately discharged from the hospital. The median time from CP transfusion to discharge in survivors was 14 days (2-103 days), while median time from CP to death in non-survivors was 10 days (1-76 days). The mean time in days both from hospital admission to CP and from positive SARS-CoV-2 polymerase chain reaction (PCR) to CP trended slightly longer in non-survivors when compared to survivors (8.6 vs 6.9 days, p=0.218 and 9.7 vs 7.3 days, p=0.85, respectively). D-dimer levels >5 milligrams per liter fibrinogen equivalent units (mg/L FEU) were associated with increased mortality at 24 (OR 2.79, 95% CI 1.18-6.72), 48 (OR 3.64, 95% CI 1.44-9.70), and 72 hours (OR 2.99, 95% CI 1.23-7.66) post-CP transfusion (Figure 3). Twelve patients (11.4%) on prophylactic or intermediate dose anticoagulation were subsequently escalated to therapeutic dosing during the 7 days after CP transfusion. Furthermore, a ferritin level of >3000 nanograms per milliliter (ng/mL) on the day of CP was associated with increased mortality (OR 5.14, 95% CI 1.34-19.68).Conclusions: CP therapy was administered through the EAP to COVID-19 patients with severe disease and with advanced age, high frequency of obesity, and extensive co-morbidity. In this COVID-19 population with high expected mortality, 42.9% of patients improved by WHO Ordinal Scale score within 7 days of CP transfusion and 52.4% were alive and discharged at 28 days. Baseline ferritin and d-dimer levels at 24, 48, and 72 hours post-CP were predictors of mortality, the latter raising the possibility that the increased thrombotic risk associated with COVID-19 may be exacerbated by administration of blood products from donors pot ntially in a residual procoagulant state. Further studies by our group are underway to assess hemostatic balance in donor CP, to estimate associations with outcomes by comparing patients who received CP with a matched control cohort of COVID-19 patients who did not receive CP, and to evaluate efficacy of CP in a randomized, placebo-controlled clinical trial.