Table 2.
Seropositivity among different study groups at various time periods in the year 2009
| Study groups | Month of 2009 | No. sampled | HI titre ≥1:10 | HI titre ≥1:40 | ||
|---|---|---|---|---|---|---|
| No. | % (95% CI) | No. | % (95% CI) | |||
| Hospital staff | August | 495 | 43 | 8.7 (6.2-11.2) | 14 | 2.8 (1.4-4.3) |
| October | 524 | 40 | 7.6 (5.4-9.9) | 25 | 4.8 (3.0-6.5) | |
| November | 385 | 77 | 20.0 (16.0-23.9) | 46 | 12.0 (8.7-15.1) | |
| General practitioners | August | 385 | 62 | 16.1 (12.4-19.8) | 19 | 4.9 (2.8-7.0) |
| November | 278 | 67 | 24.1 (19.1-29.1) | 26 | 9.4 (5.9-12.8) | |
| December | 225 | 80 | 35.6 (29.3-41.8) | 34 | 15.1 (10.4-19.8) | |
| School staff | August | 348 | 23 | 6.6 (3.9-9.2) | 7 | 2.0 (0.5-3.5) |
| September | 177 | 46 | 26.0 (19.5-32.5) | 19 | 10.7 (6.2-15.3) | |
| School children | September | 2527 | 800 | 31.7 (29.8-33.5) | 631 | 25.0 (23.3-26.7) |
| Railway commuters | September | 225 | 27 | 12.0 (7.8-16.3) | 13 | 5.8 (2.7-8.8) |
| Office staff | September | 233 | 25 | 10.7 (6.8-14.7) | 8 | 3.4 (1.0-5.8) |
| Slum-dwellers | September | 651 | 67 | 10.3 (8.0-12.6) | 23 | 3.5 (2.1-5.0) |
| General population | October | 2520 | 242 | 9.6 (8.4-10.8) | 151 | 6.0 (5.1-6.9) |
| PCR-confirmed cases | September- October | 65 | 53 | 81.5 (72.1-91.0) | 48 | 73.8 (63.2-84.5) |
| Household contacts | September- October | 195 | 70 | 35.8 (29.2-42.6) | 50 | 25.6 (19.5-31.8) |
CI = confidence interval, HI = haemagglutination-inhibition, PCR = polymerase chain reaction