Table 4 Comparison of seroprevalence of HBsAg and anti-HBs in “the same school” and “the others” groups
Item | 18-year age group (birth cohort 1993–1994) | ||
|---|---|---|---|
The same school (n = 38) | The others (n = 1256) | P-value | |
Anti-HBs (+), n (%, 95% CI) | 29 (76.3, 62.8-89.8) | 499 (39.7, 37.0-42.4) | <0.001* |
Anti-HBs (−), n (%, 95% CI) | 9 (23.7, 10.2-37.2) | 757 (60.3, 57.6-63.0) | |
Anti-HBs titer, mean ± SD (median) | 157.6 ± 281.3 (P50 = 24.7) | 58.8 ± 145.9 (P50 = 4.2) | <0.001* |
HBsAg (+), n (%) | 0 (0.0) | 10 (0.8%) | 0.581 |
HBsAg (−), n (%) | 38 (100.0) | 1246 (99.2%) | |