Design of field trials for the evaluation of transmissible vaccines in animal populations
Fig 3
Required sample sizes, NT*, for overall protection estimand (Δ1(5)) will depend on the transmissible vaccine’s protective strength, as well as on the trial design.
Our approximate formula reveals that as the R0 of the vaccine increases (left panel) or number sampled in each cluster, s, increases (middle panel), NT* for trials that measure the overall protection that transmissible vaccines confer relative to traditional vaccines will decrease. NT* will increase as the between-cluster variance in the final size proportion increases. All other parameters are set at R0,v = 1.1, number sampled from each cluster, s = 100, between cluster variance = 0.01, R0,w = 2, proportion initially recovered = 0, vaccine efficacy = 80%, initial vaccinated proportion, α = 5%.