Figure 1. Prevalence of HPV infection among female university students in Hanoi, Hue, and Ho Chi Minh City by college field, year of study, and city. Natural science major/first year (black) and social science major/fourth year (grey) students in the upper and middle panel, respectively; and north Vietnam, Hanoi (red), central Vietnam, Hue (grey) and south Vietnam, Ho Chi Minh (blue) in the lower panel. The high-risk (hr) HPV types include 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66/68 and the low-risk (lr) HPV types include 6, 11, 40, 42, 43, 44, 26, 54, 61, 63, 73, 84, 81, 55. The exact binomial method was used to estimate 95% confidence interval (CI) of HPV infection, depicted by error bars. *In x-axis indicates significant differences (p<0.05) between natural science and social science students, and first- and fourth-year students.