Table 2.
Demographic characteristics of study participants
| Characteristic | Total | ORS cases | Controls | P |
|---|---|---|---|---|
| n | 44 | 9 | 35 | |
| Female (no. [%]) | 26 (59) | 8 (89) | 18 (51) | 0.06 |
| Age (yr) | ||||
| Mean | 42.8 | 45.2 | 42.2 | 0.43 |
| Median | 43.5 | 49.0 | 41.0 | |
| Range | 24–65 | 29–54 | 24–65 | |
| Ethnic background (no. [%]) | ||||
| White | 39 (89) | 8 (89) | 31 (89) | >0.99 |
| Other | 5 (11) | 1 (11) | 4 (11) | |
| Underlying medical conditiona (no. [%]) | 24 (55) | 7 (78) | 17 (49) | 0.15 |
| Hypertension | 3 | 1 | 2 | — |
| Asthma | 6 | 4 | 2 | 0.01 |
| Allergies | 7 | 3 | 4 | 0.14 |
| Other | 17 | 5 | 12 | — |
| Previous ORSb (no. [%]) | 2 (5)c | 2 (22)c | 0 | — |
| Influenza vaccination status (no. [%]) | ||||
| Previous vaccination | 44 (100) | 9 (100) | 35 (100) | — |
| Pandemic 2009/2010 vaccine | 39 (89) | 8 (89) | 31 (89) | >0.99 |
| Seasonal vaccine last year | 40 (91) | 9 (100) | 31 (89) | 0.57 |
| Received medication within the past 24 ha (no. [%]) | 20 (48)e | 6 (86)e | 14(40) | 0.04 |
| NSAIDd | 8 | 4 | 4 | 0.08 |
| Antihistamine | 5 | 2 | 3 | 0.53 |
| Birth control or hormonal therapy | 5 | 2 | 3 | 0.27 |
| Other | 8 | 3 | 5 | — |
a
Some subjects had more than one condition.
b
Previous ORS was following a past influenza vaccine. One of the cases experienced ORS twice, and one had it once previously.
c
One missing response from an ORS case (43 total valid responses, 8 among ORS cases).
d
NSAID, nonsteroidal anti-inflammatory drugs.
e
Two missing responses in ORS cases (42 total valid responses, 7 among ORS cases).