COVID-19 Convalescent Plasma and Clinical Trials: Understanding Conflicting Outcomes

Daniele Focosi, Massimo Franchini, Liise Anne Pirofski, Thierry Burnouf, Nigel Paneth, Michael J. Joyner, Arturo Casadevall

Research output: Contribution to journalReview articlepeer-review

Abstract

Convalescent plasma (CP) recurs as a frontline treatment in epidemics because it is available as soon as there are survivors. The COVID-19 pandemic represented the first large-scale opportunity to shed light on the mechanisms of action, safety, and efficacy of CP using modern evidence-based medicine approaches. Studies ranging from observational case series to randomized controlled trials (RCTs) have reported highly variable efficacy results for COVID-19 CP (CCP), resulting in uncertainty. We analyzed variables associated with efficacy, such as clinical settings, disease severity, CCP SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) antibody levels and function, dose, timing of administration (variously defined as time from onset of symptoms, molecular diagnosis, diagnosis of pneumonia, or hospitalization, or by serostatus), outcomes (defined as hospitalization, requirement for ventilation, clinical improvement, or mortality), CCP provenance and time for collection, and criteria for efficacy. The conflicting trial results, along with both recent WHO guidelines discouraging CCP usage and the recent expansion of the FDA emergency use authorization (EUA) to include outpatient use of CCP, create confusion for both clinicians and patients about the appropriate use of CCP. A review of 30 available RCTs demonstrated that signals of efficacy (including reductions in mortality) were more likely if the CCP neutralizing titer was >160 and the time to randomization was less than 9 days. The emergence of the Omicron variant also reminds us of the benefits of polyclonal antibody therapies, especially as a bridge to the development and availability of more specific therapies.

Original languageEnglish (US)
Pages (from-to)e0020021
JournalClinical Microbiology Reviews
Volume35
Issue number3
DOIs
StatePublished - Sep 21 2022

Keywords

  • convalescent plasma
  • COVID-19
  • neutralizing antibodies
  • propensity score-matched
  • randomized clinical trial
  • viral neutralization tests

ASJC Scopus subject areas

  • Epidemiology
  • Immunology and Microbiology(all)
  • Public Health, Environmental and Occupational Health
  • Microbiology (medical)
  • Infectious Diseases

Fingerprint

Dive into the research topics of 'COVID-19 Convalescent Plasma and Clinical Trials: Understanding Conflicting Outcomes'. Together they form a unique fingerprint.

Cite this