Table 2. Seroprevalences of antibodies (HI titer ≥1: 80) to H7N9 and H5N1 viruses in poultry workers, swine workers and the general population in three cross-sectional surveys (2013–2015).
| Period | Characteristics | H7N9 | p value | H5N1 clade 2.3.4 | P value | H5N1 clade 2.3.2.1 | p value |
|---|---|---|---|---|---|---|---|
| November 2013 | Participant category | ||||||
| Poultry workers | 0/1258 (0) | 0.317‡ | 0/1258 (0) | 1.000‡ | 0/1258 (0) | 0.334‡ | |
| Swine workers | 0/1332 (0) | 1/1332 (0.1) | 2/1332 (0.2) | ||||
| General population | 1/1200 (0.1) | 0/1200 (0) | 0/1200 (0) | ||||
| Sex | |||||||
| Male | 0/1933 (0) | 0.490‡ | 1/1933 (0.1) | 1.000‡ | 2/1933 (0.1) | 0.166‡ | |
| Female | 1/1855 (0.1) | 0/1855 (0) | 0/1855 (0) | ||||
| Age group | |||||||
| <50 years | 1/2200 (0.0) | 1.000‡ | 1/2200 (0.0) | 1.000‡ | 2/2200 (0.1) | 0.513‡ | |
| ≥50 years | 0/1585 (0) | 0/1585 (0) | 0/1585 (0) | ||||
| Having underlying disease | |||||||
| No | 1/3489 (0.0) | 1.000‡ | 1/3489 (0.0) | 1.000‡ | 2/3489 (0.1) | 1.000‡ | |
| Yes | 0/301 (0) | 0/301 (0) | 0/301 (0) | ||||
| April 2014 | Participant category | ||||||
| Poultry workers | 4/1056 (0.4) | 0.008‡ | 17/1056 (1.6) | <0.001* | 2/1056 (0.2) | 0.091‡ | |
| Swine workers | 0/1254 (0) | 1/1254 (0.1) | 0/1254 (0) | ||||
| General population | 0/1188 (0) | 0/1188 (0) | 0/1188 (0) | ||||
| Sex | |||||||
| Male | 2/1686 (0.1) | 1.000‡ | 3/1686 (0.2) | 0.007* | 1/1686 (0.1) | 1.000‡ | |
| Female | 2/1807 (0.1) | 15/1807 (0.8) | 1/1807 (0.1) | ||||
| Age group | |||||||
| <50 years | 3/2018 (0.1) | 0.643‡ | 12/2018 (0.6) | 0.447* | 0/2018 (0) | 0.178‡ | |
| ≥50 years | 1/1471 (0.1) | 6/1471 (0.4) | 2/1471 (0.1) | ||||
| Having underlying disease | |||||||
| No | 4/3278 (0.1) | 1.000‡ | 17/3278 (0.5) | 1.000‡ | 2/3278 (0.1) | 1.000‡ | |
| Yes | 0/219 (0) | 1/219 (0.5) | 0/219 (0) | ||||
| April 2015 | Participant category | ||||||
| Poultry workers | 4/1123 (0.4) | 0.023‡ | 2/1123 (0.2) | 0.417‡ | 1/1123 (0.1) | 0.209‡ | |
| Swine workers | 0/998 (0) | 1/998 (0.1) | 2/998 (0.2) | ||||
| General population | 0/1135 (0) | 0/1135 (0) | 0/1135 (0) | ||||
| Sex | |||||||
| Male | 1/1595 (0.1) | 0.625‡ | 0/1595 (0) | 0.250‡ | 1/1595 (0.1) | 1.000‡ | |
| Female | 3/1658 (0.2) | 3/1658 (0.2) | 2/1658 (0.1) | ||||
| Age group | |||||||
| <50 years | 2/1871 (0.1) | 1.000‡ | 2/1871 (0.1) | 1.000‡ | 3/1871 (0.2) | 0.267‡ | |
| ≥50 years | 2/1377 (0.1) | 1/1377 (0.1) | 0/1377 (0) | ||||
| Having underlying disease | |||||||
| No | 4/2950 (0.1) | 1.000‡ | 3/2950 (0.1) | 1.000‡ | 3/2950 (0.1) | 1.000‡ | |
| Yes | 0/305 (0) | 0/305 (0) | 0/305 (0) |
Note. Data are expressed as proportion (%) of participants, unless otherwise indicated.
*Compared using Pearson’s χ2 test.
‡Compared using Fisher’s exact test.