Table 1 Multivariable meta-regression for change in seroprevalence of antibodies to highly pathogenic avian influenza A(H5N1) virus by different factors
Study characteristics | All studies (β coefficient¶, 95% CI) | All studies excluding reports related to A(H5N1) outbreaks in Hong Kong in 1997 (β coefficient, 95% CI) |
|---|---|---|
Year of study | ||
 1997–2002 | 1.0 | – |
 2003–2017 | − 1.7 (− 3.2, − 0.2)* | – |
Epidemic region | ||
 Southeast Asiaa | 1.0 | 1.0 |
 Hong Kong, China | 1.8 (− 0.0, 3.7) | – |
 Mainland China | − 0.4 (− 1.2, 0.4) | − 0.8 (− 1.5, − 0.1)* |
 Middle East and Africab | − 0.4 (− 1.4, 0.6) | − 0.6 (− 1.6, 0.4) |
 Other countriesc | − 0.7 (− 1.7, 0.3) | − 1.0 (− 2.0, − 0.1)* |
A(H5N1) outbreaks in poultry | ||
 No | 1.0 | 1.0 |
 Yes | 0.2 (− 0.5, 0.8) | − 0.1 (− 0.7, 0.5) |
Virus clade | ||
 Clade 0 | 1.0 | 1.0 |
 Clade 1 | 0.2 (− 0.8, 1.1) | − 0.0 (− 0.9, 0.9) |
 Clade 2 | 0.2 (− 0.6, 1.1) | 0.0 (− 0.8, 0.8) |
Study quality | ||
 Category B | 1.0 | 1.0 |
 Category C | − 0.2 (− 0.9, 0.6) | − 0.1 (− 0.8, 0.6) |
 Category D | 0.1 (− 1.1, 1.4) | 0.2 (− 1.0, 1.4) |
Level of exposure | ||
 Without any exposure | 1.0 | 1.0 |
 Human case contact only | − 0.1 (− 1.5, 1.3) | − 0.3 (− 1.7, 1.1) |
 Both poultry exposure and human case contact | 0.5 (− 0.4, 1.5) | 0.2 (− 0.8, 1.2) |
 Poultry exposure only | 0.6 (0.0, 1.2)* | 0.5 (− 0.0, 1.1) |