rld (version 1.0)

calcVEt: Calculate Vaccine Efficacy Before or At the Time of Challenge t

Description

This function estimates the vaccine efficacy before or at the time of challenge t. VE(t)>0 indicates that the vaccine is effective in reducing the risk of infection before or at time t, whereas VE(t)

Usage

calcVEt(object, nexposure, newdata, CIlevel = 0.95)

Arguments

object

a fitted object of class inheriting from "rld".

nexposure

a vector of challenges or exposures for all dose levels for predicting VE(t).

newdata

a data list for predicting vaccine efficacy where "contrgroup" and "refgroup" list names must be included.

CIlevel

the confidence level. The default is 0.95.

Value

Details

Vaccine efficacy for preventing infection before or at the time of challenge t, VE(t), is defined as the relative reduction in the risk of infection before or at time t for the vaccine group compared to the placebo group. Please refer to Kang et al.(2015) for more details.

References

Kang, C., Huang, Y., and Miller, C. (2015). A discrete-time survival model with random effects for designing and analyzing repeated low-dose challenge experiments. Biostatistics, 16(2): 295-310.

See Also

calcVEk, calcpk

Examples

data(SampleData)
augdata <- transdata(data = SampleData, ndlevel = 3, nexposure = c(10, 10, 2))
fitout <- rld(formula = survival::Surv(time, delta)~factor(dose)+trt+I(I(dose==3)*trt),
              data = augdata, frailty = TRUE)

contrgroup <- 1
refgroup <- 0
predata <- list(contrgroup, refgroup)
names(predata) <- c("contrgroup", "refgroup")
names(predata$contrgroup) <- c("trt")
names(predata$refgroup) <- c("trt")

VEtout <- calcVEt(object = fitout, nexposure = c(10, 10, 2), newdata = predata,
                  CIlevel = 0.95)
summary(VEtout)