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. 2023 Jul 28;14:4545. doi: 10.1038/s41467-023-40204-1

Fig. 3. Duration of protection against SARS-CoV-2 variants.

Fig. 3

Using the dose-response relationship of antibody concentration and protective efficacy in Fig. 2 and the estimated half-life of antibodies after treatment (28.9 days (95% CI: 26.6–31.6) for casirivimab/imdevimab, 94.7 days (95% CI: 83.5–109.4) for cilgavimab/tixagevimab and 134.4 days (95% CI: 132.6–136.3) for adintrevimab, see Figure S3 and Table S8), we predict the efficacy over time for these antibody combinations (black line, a–c). We also estimate the protection over time of these antibody combinations given different fold-increases in the 50% inhibitory concentration (IC50), which may be experienced toward new variants (colored lines). d For each hypothetical loss of potency of these antibodies (i.e., fold increase in IC50, x axis), we predict the number of days each antibody will remain above 50% protection. The shaded regions indicate the 95% confidence interval of the duration of protection (using the 95% CI for 50% protection: 32.4–285.2). We note that casirivimab/imdevimab, cilgavimab/tixagevimab and adintrevimab are predicted to tolerate up to a 143.8-, 56.5- and 61.1-fold drop in potency to a new variant (compared to the ancestral variant), respectively, and still be expected to maintain 30 days of >50% protective efficacy.