COVID-19 convalescent plasma administered late in the course of disease has not shown clear benefits, but some studies suggest that early transfusion may be efficacious. In order to determine if convalescent plasma administered soon after infection may help to prevent severe disease in older patients, researchers in Argentina randomized 160 patients aged 65 or older to receive either convalescent plasma (N=80) or placebo (N=80) within 72 hours of symptom onset. Patients were followed for 15 days. Only 13 of 80 patients (16%) who received convalescent plasma developed severe respiratory disease (defined as a respiratory rate of at least 30 breaths/minute and/or an oxygen saturation of less than 93% while patient was breathing ambient air) compared to 25 of 80 patients (31%) who received placebo, which reduced the risk by 48% (relative risk, 0.52; 95% C.I., 0.29 to 0.94; P=0.03). Furthermore, a dose-dependent effect was observed for SARS-CoV-2 IgG titers in convalescent plasma to treat patients; plasma with IgG titers 1:3200 or higher reduced the risk of developing severe respiratory disease by 73.3% compared to patients treated with placebo. Convalescent plasma administered early may help save lives.
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