Figure 1.

Sample selection criteria for analyses of incident HPV 6, 11, 16 and 18 infections. The final samples of women with incident HPV infections eligible for each type-specific analysis are represented within the bottom box, labeled by HPV type. These were comprised of placebo arm women with incident type-specific infections who were negative on PCR testing for the relevant HPV type on the first two trial endo/ecto-cervical swabs and any intervening cervical biopsies.