Table 1. Characteristics of study participants in the Influenza Cohort Study performed during 2009 pandemic, Toronto, Ontario, Canada*.
| Characteristic | Participant values by cohort, n = 732 |
||
|---|---|---|---|
| No. HCWs in acute care facilities, n = 563 | No. non-HCWs in office settings, n = 169 | p value | |
| Mean age, y (± SD) | 42.2 (11.3) | 45.4 (10.8) | 0.001 |
| Female sex |
478/563 (84.9) |
133/169 (78.7) |
0.06 |
| Recipient of vaccine | |||
| A(H1N1)pdm09 vaccine† | 469/554 (84.7) | 66/165 (40.0) | <0.001 |
| Seasonal influenza vaccine 2009–10 | 226/563 (40.1) | 41/169 (24.3) | <0.001 |
| Seasonal influenza vaccine 2008–09 |
407/552 (73.7) |
76/164 (46.3) |
<0.001 |
| Underlying health conditions | |||
| Asthma | 55/555 (9.9) | 14/167 (8.4) | 0.56 |
| Diabetes mellitus | 22/555 (4.0) | 5/165 (3.0) | 0.58 |
| Allergies to airborne irritants | 235/509 (46.2) | 60/155 (38.7) | 0.10 |
| Current smoker or smoker in household |
73/551 (13.3) |
27/163 (16.6) |
0.28 |
| Potential exposure conditions | |||
| Hand-to-face habits | 275/557 (49.4) | 76/168 (45.2) | 0.35 |
| Wearing of prescription eyeglasses | 386/561 (68.8) | 119/168 (70.8) | 0.62 |
| Reusable water bottle use >1/week | 232/556 (41.7) | 81/169 (47.9) | 0.15 |
| Public transit: >8 trips per week | 196/558 (35.1) | 45/168 (26.8) | 0.04 |
| Group gathering attendance | 524/563 (93.1) | 150/167 (89.8) | 0.17 |
| Face-to-face contacts/d, median (IQR) | 10 (5, 20) | 10 (5, 20) | 0.94 |
| >1 person/bedroom in household | 192/551 (34.9) | 51/166 (30.7) | 0.33 |
| Children in workplace | 62/558 (11.1) | 9/167 (5.4) | 0.03 |
| Child <5 y in household | 77/563 (13.7) | 10/169 (5.9) | 0.006 |
| Child <18 y in household | 212/563 (37.7) | 59/169 (34.9) | 0.52 |
| Child in household attends day care | 77/555 (13.9) | 16/164 (9.8) | 0.17 |
*Data are no./total (%) unless otherwise specified. HCW, health care worker; A(H1N1)pdm09, pandemic influenza A(H1N1) 2009 virus; IQR, interquartile range. †Participants who had acquired A(H1N1)pdm09 <7 d after vaccination were considered unprotected.