Figure 6. Predicted effect of vaccination on probability of recurrence (SORI model).

Simplest design to measure vaccine effectiveness with 50:50 mix of control and vaccinated herds and a target coverage of either 50 or 100% for a 3-year trial period. We explore a range of assumed vaccine-induced reductions in susceptibility (A,B) ${\mathit{\epsilon }}_{\mathit{S}}=60\mathit{\%}$(C,D) ${\displaystyle {\mathit{\epsilon }}_{\mathit{S}}=60\mathbf{\%}}$(E,F) ${\displaystyle {\mathit{\epsilon }}_{\mathit{S}}=90\mathrm{\%}}$ and infectiousness (${\displaystyle {\mathit{\epsilon }}_{\mathit{I}}}$ = 0, 30, 60, 90%). For an assumed vaccine efficacy of 90% (reduction in susceptibility), the SORI model predicts a ~ 15% reduction in prolonged breakdowns (defined as the proportion of herds that take more than 1 short interval test to clear restrictions) for 100% vaccination coverage and ~ 5% for 50%. For this effect size, ~ 500 herds would be required to achieve the target 80% trial power for whole herd vaccination. In excess of 2000 herds (the upper range considered) would be required for a 50% within herd target coverage.

Figure 6—figure supplement 1. Posterior predictive distribution for effect size of vaccination on probability of recurrence (SORI model).

Posterior predictive distribution of the % difference in the probability of a recurrent breakdown (effect size) between vaccinated and control herds for a 3-year trial duration for the SORI model plotted against herd size. Median value is plotted as a solid line, with shaded region illustrating 95% credible intervals for 100% within-herd target coverage of vaccination (black) and 50% target coverage (orange). Plotted distributions are for an assumed reduction in susceptibility of ${\displaystyle {\mathit{\epsilon }}_{\mathit{S}}=90\mathrm{\%}}$ and the reduction in infectiousness ${\displaystyle {\mathit{\epsilon }}_{\mathit{I}}}$ as indicated in the heading of each panel.

Figure 6—figure supplement 2. Predicted effect of vaccination on probability of recurrence (SOR model).

Simplest design to measure vaccine effectiveness with 50:50 mix of control and vaccinated herds and a target coverage of either 50 or 100% for a 3-year trial period. We explore a range of assumed vaccine-induced reductions in susceptibility (A,B) ${\mathit{\epsilon }}_{\mathit{S}}=60\mathit{\%}$(C,D) ${\displaystyle {\mathit{\epsilon }}_{\mathit{S}}=60\mathbf{\%}}$(E,F) ${\displaystyle {\mathit{\epsilon }}_{\mathit{S}}=90\mathrm{\%}}$ and infectiousness (${\displaystyle {\mathit{\epsilon }}_{\mathit{I}}}$ = 0, 30, 60, 90%). For an assumed vaccine efficacy of 90% (reduction in susceptibility), the SOR model predicts a ~ 15% reduction in prolonged breakdowns (defined as the proportion of herds that take more than 1 short interval test to clear restrictions) for 100% vaccination coverage and ~ 5% for 50%. For this effect size, ~ 300 herds would be required to achieve the target 80% trial power for whole herd vaccination. In excess of 2000 herds (the upper range considered) would be required for a 50% within herd target coverage.

Figure 6—figure supplement 3. Posterior predictive distribution for effect size of vaccination on probability of recurrence (SOR model).

Posterior predictive distribution of the % difference in the probability of a prolonged breakdown (effect size) between vaccinated and control herds for a 3-year trial duration for the SOR model plotted against herd size. Median value is plotted as a solid line, with shaded region illustrating 95% credible intervals for 100% within-herd target coverage of vaccination (black) and 50% target coverage (orange). Plotted distributions are for an assumed reduction in susceptibility of ${\displaystyle {\mathit{\epsilon }}_{\mathit{S}}=90\mathrm{\%}}$ and the reduction in infectiousness ${\displaystyle {\mathit{\epsilon }}_{\mathit{I}}}$as indicated in the heading of each panel.