Table 1. Human seroprevalence and seroconversion data for the IAV antigens A/H1pdm, A/H3 and avian A/H9, stratified by age at enrolment. Seropositives were defined as HI titre ≥40 at each of the three sampling time points.
| A/H1pdm positives (%) | A/H3 positives (%) |
A/H9 positives (%) | Seroconverters | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Age group (year) | No. of participants (%) | Median age, IQR (year) | Male sex (%) | Year 0 | Year 1 | Year 2 | Year 0 | Year 1 | Year 2 | Year 0 | Year 1 | Year 2 | A/H1pdm | A/H3 | A/H9 |
| 0–9 | 6/265 (2.3) |
8 (8) |
2/6 (33) | 2/5 (40) | 2/6 (33) | 4/6 (66) | 3/5 (60) | 6/6 (100) | 5/6 (83) | 0/5 (0) | 0/6 (0) | 1/6 (16) | 1/6 (17) | 2/6 (33) | 1/6 (17) |
| 10–20 | 36/265 (13.6) |
15.5 (13–19) |
14/36 (39) | 19/33 (57) | 25/36 (69) | 18/35 (51) | 26/33 (79) | 30/36 (83) | 30/35 (86) | 0/33 (0) | 0/36 (0) | 4/35 (11) | 8/36 (22) | 14/36 (39) | 4/36 (11) |
| 21–50 | 158/265 (59.6) |
38 (31–45.2) |
62/158 (39) | 63/154 (41) | 72/157 (46) | 70/145 (48) | 80/154 (52) | 99/157 (63) | 90/145 (62) | 5/154 (3) | 7/157 (4) | 9/145 (6) | 33/158 (21) | 61/158 (39) | 16/158 (10) |
| >50 | 65/265 (24.5) |
56 (53–70) |
30/65 (46) | 15/64 (23) | 15/64 (23) | 19/57 (33) | 28/64 (44) | 34/64 (53) | 31/57 (54) | 0/64 (0) | 2/64 (3) | 0/57 (0) | 13/65 (20) | 18/65 (28) | 2/65 (3) |
| Overall | 265 | 40 (27–50) |
108 (40.8) | 99/256 (38.6) | 114/263 (43.3) | 111/243 (45.6) | 137/256 (53.5) | 169/263 (64.2) | 156/243 (64.2) | 5/256 (1.9) | 9/263 (3.4) | 14/243 (5.7) | 55/265 (20.7) | 95/265 (35.8) | 23/265 (8.6) |