TABLE 2.
Select randomized controlled trials of COVID-19 convalescent plasma
| Antibody titer threshold | Conclusion | |
|---|---|---|
| Adults hospitalized with severe COVID-19 pneumonia | ||
| Li et al.25 | 1:640 or greater anti-RBD | No effect on clinical improvement within 28 days |
| Simonovich et al.26 | >1:400 anti-spike | No effect on 30 day mortality |
| Agarwal et al.27 | None | No effect on progression or mortality at 28 days |
| RECOVERY group28 | ≥1:100 neutralizinga | No effect on 28 day mortality |
| Adults with early COVID-19 disease | ||
| Libster et al.29 | >1:1000 anti-spike | 0.20–0.81 relative risk reduction for severe respiratory disease |
Abbreviations: ELISA, enzyme-linked immunosorbed assay; RBD, receptor binding domain.
a
IgG ELISA with sample to cutoff ratio of ≥6.0, previously shown to be associated with neutralizing antibody titers ≥1:100.