Volume 19, Number 1—January 2013
Research
Seroepidemiologic Effects of Influenza A(H1N1)pdm09 in Australia, New Zealand, and Singapore
Table 4
Multivariate logistic regression models on outcome of pre- and postpandemic seropositivity in community-based studies of influenza A (H1N1) 2009 in the Southern Hemisphere with exposure variables of region, age group, and sex, winter 2009*
| Exposure variable | Prepandemic phase, n = 4,289 |
Postpandemic phase, n = 5,650 |
|||
|---|---|---|---|---|---|
| Odds ratio (95% CI) | p value | Odds ratio (95% CI) | p value | ||
| Region | |||||
| New South Wales† | 1 | 1 | |||
| New Zealand | 1.18 (0.77–1.80) | 0.45 | 1.44 (1.17–1.79) | 0.001 | |
| Northern Territory | 0.62 (0.38–1.02) | 0.06 | 0.82 (0.66–1.01) | 0.06 | |
| Queensland | 1.25 (0.79–1.98) | 0.34 | 0.78 (0.53–1.14) | 0.20 | |
| Singapore | 0.40 (0.27–0.61) | <0.001 | 0.56 (0.43–0.74) | <0.001 | |
| Tasmania | 1.50 (0.95–2.35) | 0.08 | |||
| Victoria | 1.37 (0.94–2.01) | 0.11 | |||
| Western Australia |
0.41 (0.25–0.67) |
<0.001 |
1.04 (0.76–1.43) |
0.79 |
|
| Age group, y | |||||
| 0–4† | 1 | 1 | |||
| 5–14 | 2.34 (0.92–5.92) | 0.07 | 1.60 (1.24–2.06) | <0.001 | |
| 15–34 | 13.70 (5.85–32.07) | <0.001 | 1.50 (1.18–1.91) | 0.001 | |
| 35–54 | 6.24 (2.50–15.57) | <0.001 | 0.75 (0.58–0.98) | 0.04 | |
| 55–74 | 14.60 (5.98–35.62) | <0.001 | 0.73 (0.56–0.95) | 0.02 | |
| ≥75 |
47.43 (18.58–121.08) |
<0.001 |
0.95 (0.64–1.41) |
0.80 |
|
| Sex | |||||
| F† | 1 | 1 | |||
| M | 0.99 (0.73–1.34) | 0.96 | 0.97 (0.85–1.24) | 0.70 | |
| Unknown | 2.44 (1.74–3.42) | <0.001 | 1.67 (1.25–2.24) | 0.001 | |
*Blank cells indicate no data. The 2 regression models are displayed vertically.
†Reference category.
1A list of the group’s members can be found at the end of this article.


