Convalescent Plasma Therapy, Therapeutic Formulations of Repurposed Drugs in 20th Century Epidemics against COVID-19: A Systematic Review

Coronavirus 2019 disease (COVID-19) represents one of the largest pandemics the world has faced, and it is producing a global health crisis. To date, the availability of drugs to treat COVID-19 infections remains limited to supportive care although therapeutic options are being explored. Some of them are old strategies for treating infectious diseases. convalescent plasma (CP) therapy has been used successfully in other viral outbreaks in the 20th century. In this study, we systematically evaluated the effect and safety of CP therapy on hospitalized COVID-19 patients. A structured search was conducted following the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines using Medline (PubMed), SciELO, Cochrane Library Plus, Web of Science, and Scopus. The search included articles published up to January 2022 and was restricted to English- and Spanish-language publications. As such, investigators identified six randomized controlled trials that met the search criteria. The results determined that in hospitalized COVID-19 patients the administration of CP therapy with a volume between 200–500 mL and a single transfusion performed in 1–2 h, compared to the control group, decreased viral load, symptomatology, the period of infection, and mortality, without serious adverse effects. CP did influence clinical outcomes and may be a possible treatment option, although further studies will be necessary.