Use of convalescent plasma in COVID-19: is clinical severity more important than the intervention?

Abstract

Background COVID-19 convalescent plasma (CCP) was used in the early period of the pandemic, but the effectivity of this treatment showed different results, especially because of the possible ineffectiveness of passive antibodies, when an inflammatory response is already established. Objectives: The aim of this study is to compare the outcomes of two different cohorts of COVID-19 patients that received CCP transfusion in the years 2020 and 2021. Design and setting: This is a retrospective study from a tertiary hospital in São Paulo, Brazil. Methods: We included a retrospective cohort of patients that received convalescent compassionate plasma and another group with patients from a previous clinical study. We collected clinical and laboratory data on the day of transfusion and five days later. Patients with hematological or immunological conditions were excluded. A p-value < 0·05 was considered significant.Results CCP did not show to interfere in the outcomes of severe COVID-19 patients, when comparing two different cohorts transfused with different volumes and titles of neutralizing antibodies. Despite the improvement in some laboratory parameters, there was not impact on clinical outcomes. Dialysis had a negative impact on the ICU stay, days of hospitalization and days of mechanical ventilation. Each higher point on the day 0 WHO scale reduced the probability of hospital and ICU discharge, and the risk of mechanical ventilation discontinuation. Conclusions: In conclusion, the use of dialysis and the assessed clinical severity represented by WHO scale on day 0 had influence on the outcomes, but not the CCP transfusion.