Convalescent Plasma and Other Antibody Therapies for Infectious Diseases-Lessons Learned from COVID-19 and Future Prospects.

Antiviral passive antibody therapy includes convalescent plasma, hyperimmune globulin, and monoclonal antibodies. Passive antibodies have proven effective in reducing morbidity and mortality for SARS-CoV-2 and other infectious diseases when given early in the disease course with sufficiently high specific total and neutralizing antibody levels. Convalescent plasma can be delivered to patients before vaccination implementation or novel drug production. Carefully designed and executed randomized controlled trials near the pandemic outset are important for regulatory bodies, healthcare workers, guideline committees, the public, and the government. Unfortunately, many otherwise well-designed antibody-based clinical trials in COVID-19 were futile, either because they intervened too late in the disease or provided plasma with insufficient antibodies. The need for early treatment mandates outpatient clinical trials in parallel with inpatient trials. Early outpatient COVID-19 convalescent plasma transfusion with high antibody content within 9 days of symptom onset has proven effective in blunting disease progression and reducing hospitalization, thus reducing hospital overcrowding in a pandemic. Convalescent plasma offers the opportunity for hope by enabling community participation in outpatient curative therapy while monoclonal therapies, vaccines, and drugs are being developed. Maintaining the appropriate infrastructure for antibody infusion in both outpatient and inpatient facilities is critical for future pandemic readiness.