Design of field trials for the evaluation of transmissible vaccines in animal populations
Table 4
Estimated overall protection from and required sample sizes, NT*, for anticipatory trials comparing a transmissible vaccine to a pure control group with no vaccination. Clusters are either vaccinated at a rate of α%=5% prior to the outbreak with a transmissible vaccine or do not receive any vaccination. The contact structure is Poisson distributed and trials are anticipatory. Δ1(5) is the overall protection. Vax. Eff. is the true direct efficacy of the vaccine to decrease susceptibility of vaccinated animals. R0,v refers to the R0 of the vaccine. Estimate protection is the mean estimate of the overall protection conferred by transmissible vaccines compared to traditional vaccines. <.> indicates the mean 95% confidence interval width. Req. sample size from simulation, NT*, is the number of clusters and number of animals required to estimate the effect in order to achieve at least 80% power. Power is the percentage of simulations with a p-value ≤ 5% across 1000 trial simulations. Type I error is the percentage of simulations with a p-value ≤ 5% across 3000 trial simulations for this sample size with a traditional vaccine.