A meta-analysis on the efficacy of BCG vaccination against tuberculosis (TB).
A data frame with 13 observations on the following 7 variables.
an identifier of the study.
the number of subjects suffering from TB after a BCG vaccination.
the number of subjects with BCG vaccination.
the number of subjects suffering from TB without BCG vaccination.
the total number of subjects without BCG vaccination.
geographic position of the place the study was undertaken.
the year the study was undertaken.
Bacille Calmette Guerin (BCG) is the most widely used vaccination in the world. Developed in the 1930s and made of a live, weakened strain of Mycobacterium bovis, the BCG is the only vaccination available against tuberculosis today. Colditz et al. (1994) report data from 13 clinical trials of BCG vaccine each investigating its efficacy in the treatment of tuberculosis. The number of subjects suffering from TB with or without BCG vaccination are given here. In addition, the data contains the values of two other variables for each study, namely, the geographic latitude of the place where the study was undertaken and the year of publication. These two variables will be used to investigate and perhaps explain any heterogeneity among the studies.
G. A. Colditz, T. F. Brewer, C. S. Berkey, M. E. Wilson, E. Burdick, H. V. Fineberg and F. Mosteller (1994), Efficacy of BCG vaccine in the prevention of tuberculosis. Meta-analysis of the published literature. Journal of the American Medical Association, 271(2), 698–702.
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data("BCG", package = "HSAUR3") ### sort studies w.r.t. sample size BCG <- BCG[order(rowSums(BCG[,2:5])),] ### to long format BCGlong <- with(BCG, data.frame(Freq = c(BCGTB, BCGVacc - BCGTB, NoVaccTB, NoVacc - NoVaccTB), infected = rep(rep(factor(c("yes", "no")), rep(nrow(BCG), 2)), 2), vaccined = rep(factor(c("yes", "no")), rep(nrow(BCG) * 2, 2)), study = rep(factor(Study, levels = as.character(Study)), 4))) ### doubledecker plot library("vcd") doubledecker(xtabs(Freq ~ study + vaccined + infected, data = BCGlong))