The efficacy of convalescent plasma for coronavirus disease 2019 (COVID-19) is unclear. Although most randomized controlled trials have shown negative results, uncontrolled studies have suggested that the antibody content could influence patient outcomes. We conducted an open-label, randomized controlled trial of convalescent plasma for adults with COVID-19 receiving oxygen within 12 d of respiratory symptom onset (NCT04348656). Patients were allocated 2:1 to 500 ml of convalescent plasma or standard of care. The composite primary outcome was intubation or death by 30 d. Exploratory analyses of the effect of convalescent plasma antibodies on the primary outcome was assessed by logistic regression. The trial was terminated at 78% of planned enrollment after meeting stopping criteria for futility. In total, 940 patients were randomized, and 921 patients were included in the intention-to-treat analysis. Intubation or death occurred in 199/614 (32.4%) patients in the convalescent plasma arm and 86/307 (28.0%) patients in the standard of care arm—relative risk (RR) = 1.16 (95% confidence interval (CI) 0.94–1.43, P = 0.18). Patients in the convalescent plasma arm had more serious adverse events (33.4% versus 26.4%; RR = 1.27, 95% CI 1.02–1.57, P = 0.034). The antibody content significantly modulated the therapeutic effect of convalescent plasma. In multivariate analysis, each standardized log increase in neutralization or antibody-dependent cellular cytotoxicity independently reduced the potential harmful effect of plasma (odds ratio (OR) = 0.74, 95% CI 0.57–0.95 and OR = 0.66, 95% CI 0.50–0.87, respectively), whereas IgG against the full transmembrane spike protein increased it (OR = 1.53, 95% CI 1.14–2.05). Convalescent plasma did not reduce the risk of intubation or death at 30 d in hospitalized patients with COVID-19. Transfusion of convalescent plasma with unfavorable antibody profiles could be associated with worse clinical outcomes compared to standard care.

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Although it was not universally effective and the mechanisms of its effects are unclear, AMT is a simple behavioral technique that may be useful in reducing reactions to blood donation.

To test the prediction that sweet taste modifies responses to cold induced pain, 72 young adults held sweet, bitter and water solutions in their mouths, in counterbalanced order, before and during a cold pain stimulus. To test whether or not blood pressure interacts with sweet taste analgesia, measurements of resting blood pressure were also obtained. A significant main effect of taste on pain tolerance was observed, as well as a significant interaction between resting mean arterial pressure (MAP) and taste on tolerance. Sweet taste was associated with a prolongation of tolerance compared to the bitter and water conditions. When participants were split along the median for MAP, sweet taste was associated with an 18.1% increase in pain tolerance compared with water for those with lower MAP. No significant impact of taste on pain sensitivity was observed among participants with higher MAP. Groupwise comparisons revealed a significant difference in pain tolerance between participants with higher and lower MAP in the water condition but not in the sweet condition, replicating previous findings of a reduced sensitivity to pain among those with higher blood pressure. The analgesic effects of sweet tasting solutions seen previously in human infants and children may also be present in adults. Individuals with higher blood pressure may not be as sensitive to the presumably opioid-mediated analgesic effects of sweet taste, perhaps due to opioid dysregulation.

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