Table 1.
Seroprevalence of anti-HBs lower than 10 IU/L and antibody titer for all students and the two cohorts vaccinated before or after the first year of age according to sex also. The last column shows the time between the last vaccine dose and the antibody analysis.
| Students | n | <10 IU/L | % | χ2 | p | Titer IU/L Mean ± SD | p | Time Mean ± SD |
|---|---|---|---|---|---|---|---|---|
| All students | 11,188 | 3679 | 32.9 | 11.144 | =0.0008 * | 166.0 ± 288.7 | <0.0001 * | 15.3 ± 4.9 |
| males | 3897 | 1361 | 34.9 | 143.3 ± 265.5 | 15.9 ± 4.7 | |||
| females | 7291 | 2318 | 31.8 | 178.2 ± 299.8 | 15.1 ± 5.0 | |||
| Age at vaccination | ||||||||
| Vaccinated before 1 year of age | 6013 | 3017 | 50.2 | 1759.371 | <0.0001 ** | 50.1 ± 127.9 | <0.0001 ** | 19.4 ± 1.1 |
| males | 2179 | 1080 | 49.6 | 0.472 | n.s. | 51.8 ± 129.7 | n.s. | 19.5 ± 1.0 |
| females | 3834 | 1937 | 50.5 | 49.1 ± 126.8 | 19.3 ± 1.1 | |||
| Vaccinated after 1 year of age | 5175 | 662 | 12.8 | 300.7 ± 357.1 | 10.7 ± 3.2 | |||
| males | 1718 | 281 | 16.4 | 28.805 | <0.0001 * | 259.3 ± 338.4 | <0.0001 * | 11.3 ± 3.2 |
| females | 3457 | 381 | 11.0 | 321.3 ± 364.3 | 10.3 ± 3.1 |
* Statistical significance of the differences between males and females, where females have a lower percentage of anti-HBs lower than 10 IU/L and a higher antibody titer; ** statistical significance of the differences between all students vaccinated before or after one year of age. n.s. = not significant