Figure 3From: The association of HPV-16 seropositivity and natural immunity to reinfection: insights from compartmental models SIRS models: SIRS 1 (top left), SIRS 2 (top right), SIRS 3 (bottom left) and SIRS 4 (bottom right); “+” and “-” denote seropositivity and seronegativity, respectively. Back to article page