Table 2. Characteristics of clinical and nonclinical participants at 4 hospitals at study entry (unless otherwise specified) who were infected with pandemic (H1N1) 2009, Australia, August 24–December 16, 2009*.
| Factor | Clinical participants, n = 231 | Nonclinical participants, n = 215 |
|---|---|---|
| Antibody titer >40 | 46 (19.9) | 33 (15.3) |
| Mean age, y (range) | 35.1 (19.8–56.6) | 43.2 (18.5–74.1) |
| Female gender | 157 (68.0) | 153 (71.2) |
| Seasonal vaccination 2009 | 163 (70.1) | 141 (65.6) |
| Previous seasonal vaccination | 187 (80.0) | 152 (70.7) |
| Reported confirmed pandemic (H1N1) 2009 influenza virus infection | 1 (0.4) | 0 |
| Other influenza-like illness | 155 (67.1) | 118 (54.9) |
| Oseltamivir prophylaxis | 13 (5.6) | 1 (0.5) |
| Community contact with influenza | 42 (18.2) | 46 (21.4) |
| Median no. children <18 years in household (range) | 0 (0–7) | 0 (0–3) |
| Nasal swab taken during study | 30 (12.9) | 16 (7.4) |
| Mean no. hours worked per week (range) | 39.2 (8–90) | 37.9 (6–86) |
*Values are no. (%) except as indicated.