Convalescent Plasma Not Effective for COVID-19 Treatment

In the absence of other effective therapies, convalescent plasma — first tested against diphtheria and tetanus in the late 19th century — has been tested for COVID-19. Observational reports and small studies have had variable results so far. Now, researchers have published the first randomized open-label trial of convalescent plasma for treatment of moderate COVID-19 (PaO₂/FiO₂ between 200 and 300 mm Hg or respiratory rate >24/min and oxygen saturation ≤93% on room air) involving 464 adults in 39 tertiary care hospitals across India. All patients received antiviral agents, antibiotics, and immunomodulators or corticosteroids. In addition, 235 were assigned to two doses of 200-mL convalescent plasma, one at randomization and one 24 hours thereafter. The plasma was donated by 262 individuals (94% with mild disease) a median of 41 days after reverse transcription–polymerase chain reaction confirmation of COVID-19. Of the donors, 64% had neutralizing antibody titers >1:20 (median titer, 1:40).

Demographics, comorbidities, and comedications were well balanced between the groups. Neutralizing antibodies were present in 83% of participants at enrollment. Antibody titers in the intervention and control groups did not differ through day 7. Progression to severe disease (PaO₂/FiO₂ <100 mm Hg; 19% vs. 18%) or 28-day mortality (15% vs. 14%) was similar between the groups, as were inflammation markers and severity-of-disease scores. Neutralizing antibody titers in the plasma preparations did not affect outcomes. Only resolution of shortness of breath and fatigue, and conversion to SARS-CoV-2 RNA negativity at day 7, occurred more frequently among plasma recipients.