Table 1.
Antibody loss at follow-up in responders to primary immunization.
| Characteristics | HCWs | Anti-HBs Negative | Person-Years | Antibody Loss | ||||
|---|---|---|---|---|---|---|---|---|
| N | (%) | N | (%) | Incidence Density/1000 Person-Years | Adjusted RR (CI 95%) | p | ||
| Overall | 539 | 100.0 | 29 | 5.4 | 10414.6 | 2.8 | ||
| Titers after primary immunization | ||||||||
| 10–99 | 8 | 1.5 | 8 | 100.0 | 153.6 | 52.1 | - | - |
| 100–999 | 37 | 6.9 | 8 | 21.6 | 707.6 | 11.3 | 0.28 (0.10–0.80) | 0.018 |
| ≥1000 | 494 | 91.7 | 13 | 2.6 | 9553.3 | 1.4 | 0.03 (0.01–0.09) | 0.000 |
| Sex | ||||||||
| Females | 441 | 81.8 | 22 | 5.0 | 8623.1 | 2.6 | 1.0 (0.40–2.50) | 0.986 |
| Male | 98 | 18.2 | 7 | 7.1 | 1791.5 | 3.9 | - | - |
| Age group | ||||||||
| ≤20 | 267 | 49.5 | 9 | 3.4 | 5284.4 | 1.7 | - | - |
| 21+ | 272 | 50.5 | 20 | 7.4 | 5130.2 | 3.9 | 1.3 (0.50–3.20) | 0.556 |
| Type of vaccine | ||||||||
| Plasma-derived | 219 | 40.6 | 8 | 3.7 | 4444.5 | 1.8 | - | - |
| Yeast-derived | 320 | 59.4 | 21 | 6.6 | 5970.1 | 3.5 | 2.1 (0.86–4.98) | 0.107 |