Figure 3From: Human papillomavirus (HPV) types 16, 18, 31, 45 DNA loads and HPV-16 integration in persistent and transient infections in young women Cumulative positivity rate for infections with HPV types 16, 18, 31, and 45 according to tertiles of cumulative viral load for these 4 types. Unit of analysis is an individual infection episode, which makes observations not independent as a subject may contribute multiple episodes. Dotted line: upper tertile; dashed line: middle; solid line: lower tertile viral load.Back to article page