Table 2. Booster history of all interviewed participants.
| Inclusiona | Follow-up 2008b | Follow-up 2009c | |
|---|---|---|---|
| All interviewed participants, n | 507 | 465 | 428 |
| Booster dose received, n | 507 | 461 | 428 |
| No, n (%) | 498 (98.2) | 418 (90.7) | 414 (96.7) |
| Yes, n (%) | 9 (1.8) | 43 (9.3) | 14 (3.3) |
| Booster doses, n (%) | 504 | 459 | 428 |
| 0 booster doses | 498 (98.8) | 418 (91.1) | 414 (96.7) |
| 1–2 booster doses | 6 (1.2) | 40 (8.7) | 13 (3.0) |
| 3–4 booster doses | 0 (0.0) | 0 (0.0) | 1 (0.2) |
| 5–6 booster doses | 0 (0.0) | 1 (0.2) | 0 (0.0) |
The subjects receiving booster vaccination included both those who received boosters due to a subsequent exposure and those who received boosters due to a serological result ≤0.5 IU/mL.
a Boosted at inclusion (i.e., 2 years after vaccination)
b Boosted 3 years after vaccination
c Boosted 4 years after vaccination