Table 2 Parameter estimates for the viral dynamic model

From: Randomized controlled trial of molnupiravir SARS-CoV-2 viral and antibody response in at-risk adult outpatients

Parameter

Estimate (95%CI)

IIV (%CV)

δ (d-1)

0.96 (0.93, 0.993)

12.4

V(0) (log10 cp/mL)

7.189 (7.081, 7.298)

74.7

Additive error (log10 cp/mL)

1.002

–

βmol_on

1.766 (1.653, 1.888)

–

βmol_off

0.422 (0.354, 0.502)

–

βsex

1.248 (1.113, 1.398)

–

βage

0.833 (0.492, 1.173)

–

βab

−1.109 (−1.622, −0.654)

–

βsym

−0.870 (−1.113, −0.626)

–

  1. The slope, δ, is the first-order decline rate in viral load, whereas the intercept (V(0)) the baseline viral load. Inter-individual variability (IIV) was assumed to follow a log-normal distribution for δ and log10 for V(0). Additive error is the variance of the residual error term. The following covariates all significantly (p < 0.01) improved model fit: βmol_on refers to the fractional change in delta when on molnupiravir, βmol_off refers to the fractional change in delta in the post-molnupiravir treatment period. βsex is the change in baseline viral load in males. βage is the allometric exponent relating age with V(0). βab is the allometric exponent for the inverse relationship of V(0) load and spike antibody. βsym is the allometric exponent for the inverse relationship between V(0) and time since symptom onset. The final model describing viral load with time (V(t)) was therefore: \({{{{{\rm{V}}}}}}({{{{{\rm{t}}}}}})={{{{{\rm{V}}}}}}(0){\beta }_{{{{{{\rm{sex}}}}}}}{{{{{{\rm{I}}}}}}}_{{{{{{\rm{male}}}}}}}{({{{{{{\rm{age}}}}}}}_{{{{{{\rm{i}}}}}}}/{{{{{{\rm{age}}}}}}}_{{{{{{\rm{median}}}}}}})}^{\beta {{{{{\rm{age}}}}}}}{({{{{{\rm{A}}}}}}{(0)}_{{{{{{\rm{i}}}}}}}/{{{{{\rm{A}}}}}}{(0)}_{{{{{{\rm{median}}}}}}})}^{\beta {{{{{\rm{ab}}}}}}}{({{{{{{\rm{tsym}}}}}}}_{{{{{{\rm{i}}}}}}}/{{{{{{\rm{tsym}}}}}}}_{{{{{{\rm{median}}}}}}})}^{\beta {{{{{\rm{sym}}}}}}}\exp \{-{{{\delta}}}\,{{{{{\rm{t}}}}}}\,{{{{{{\rm{I}}}}}}}_{{{{{{\rm{mol}}}}}}1}{\beta }_{{{{{{\rm{mol}}}}}}\_{{{{{\rm{on}}}}}}}{{{{{{\rm{I}}}}}}}_{{{{{{\rm{mol}}}}}}2}{\beta }_{{{{{{\rm{mol}}}}}}\_{{{{{\rm{off}}}}}}}\}\) where Imale is an indicator for male participants; age, A(0) and tsym are the individual and population median age in years, log10 spike antibody baseline and tsym time since symptom onset respectively; Imol1 and Imol2 are time-varying indicators for the molnupiravir arm during and post-treatment.
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