Fig. 3.

Prevalence differences reported in observational studies for V (a and b) and NV (c and d) high-risk genotypes by study design: post-vs.-prevaccine (a and c) and vaccinated-vs.-unvaccinated (b and d), according to vaccine coverage (colour gradient from yellow, low coverage to purple, high coverage) and sample size (dot size from small, low sample size to large, large sample size). Vertical intervals correspond to reported 95% confidence intervals while horizontal lines correspond to the time span covered.