Table 1.

Incidence rates of initial infection and of reinfection, overall and for grouped HPV types

HPV groupCategoriesInitial infectionReinfection
N*Women-monthsRate (95% CI)Nwith the same typewith a different type
Women-monthsRate (95% CI)Women-monthsRate (95% CI)
All types1,81483,6329.6 (9.0–10.3)56613,0621.5 (0.9–2.3)16,1559.7 (8.3–11.3)
Species32,129131,3042.1 (1.9–2.4)1614,1791.9 (1.0–3.8)4,4725.1 (3.4–7.7)
52,146135,5451.3 (1.1–1.5)1193,7470.8 (0.3–2.5)3,7371.1 (0.4–2.9)
62,123132,5961.7 (1.5–1.9)1464,5701.8 (0.9–3.5)4,4820.9 (0.3–2.4)
72,102129,8512.1 (1.8–2.3)1825,3221.3 (0.6–2.8)5,6002.9 (1.8–4.7)
92,047117,2083.9 (3.5–4.3)2988,2471.0 (0.5–1.9)9,1094.4 (3.2–6.0)
102,146136,7441.2 (1.0–1.4)1003,0201.7 (0.7–4.0)2,9390.7 (0.2–2.7)
Grouped species12,139134,5901.6 (1.4–1.8)1213,5951.4 (0.6–3.3)3,5351.1 (0.4–3.0)
21,91196,9697.0 (6.5–7.5)48412,5141.2 (0.7–2.0)14,5136.8 (5.5–8.2)
32,123130,0362.3 (2.1–2.6)1734,4381.8 (0.9–3.6)4,8345.4 (3.7–7.9)

NOTE: Incidence rates of initial infection and of reinfection per 1,000 women-months. Ludwig-McGill cohort, Brazilian women (1993–2004).

  • *N = number of women. Because incidence rates are reported, women included in the analysis were originally free of infection with HPV that belongs to that group (N varies according to HPV group).

  • N = number of women. To be included in the analysis, women must have been infected with a type that belongs to that group and then clear the infection for at least three consecutive visits (see text for details).

  • Species grouping based on phylogenetic and biological relatedness (group 1: benign; cervical and vaginal; group 2: cervical; and group 3, vaginal) according to Schiffman and colleagues (20). See text for details.