Fig. 2

a Forest plot for the risk of hepatitis C infection among needle exchange program participants. The black squares represent the risk of hepatitis C infection observed in each study with the 95% confidence intervals represented by the lines on each side of the squares. The diamond represents the pooled risk of hepatitis C infection with the 95% confidence interval indicated by the left and right extremes of the diamond. b Influence analysis for the risk of hepatitis C infection among needle exchange program participants. Influence analysis for point estimate changes in the risk of hepatitis C infection with each individual study deleted from the model once. c Cumulative meta-analysis for the risk of hepatitis C infection among needle exchange program participants. The results of each corresponding study, ordered by year of publication from oldest to newest, are pooled with all studies preceding it