Volume 17, Number 3—March 2011
Research
Swine Influenza Virus Antibodies in Humans, Western Europe, 2009
Nancy A. Gerloff, Jacques R. Kremer, Emilie Charpentier, Aurélie Sausy, Christophe M. Olinger, Pierre Weicherding, John Schuh, Kristien Van Reeth, and Claude P. Muller
Table 1
Characteristics of persons tested for 3 influenza viruses, Luxembourg, 2008–2009*
| Characteristic |
Swine workers, no. (%),† n = 211 |
Controls, no. (%),‡ n = 224 |
| Sex | ||
| M | 143 (67.8) | 151 (67.4) |
| F |
68 (32.2) |
73 (32.6) |
| Age group, y§ | ||
| 18–40 | 69 (32.7) | 80 (35.7) |
| 41–50 | 59 (28) | 58 (25.9) |
| 51–60 | 39 (18.5) | 41 (18.3) |
| 61–94 |
44 (20.9) |
45 (20.1) |
| Profession | ||
| Farmer | 133 | NA |
| Slaughterhouse worker | 51 | NA |
| Other¶ |
27 |
NA |
| Years worked with swine | ||
| <1 | 4 (1.9) | NA |
| 1–4 | 26 (12.3) | NA |
| 5–10 | 26 (12.3) | NA |
| >10 | 155 (73.5) | NA |
| Unknown |
0 |
224 |
| Frequency of swine contact | ||
| Rarely | 3 (1.4) | NA |
| Monthly | 2 (0.9) | NA |
| Weekly | 25 (11.8) | NA |
| Daily | 179 (84.8) | NA |
| Unknown |
2 (0.9) |
NA |
| Frequency of close contact (<1 m) with swine | ||
| Never | 1 (0.5) | NA |
| Rarely | 3 (1.4) | NA |
| Occasionally | 10 (4.7) | NA |
| Often | 22 (10.4) | NA |
| Always |
175 (82.9) |
NA |
| Self-reported influenza vaccine in past 5 y | ||
| No/unsure | 155 (73.5) | NA |
| Yes |
56 (26.5) |
NA |
| Self-reported infection with seasonal influenza | ||
| No | 145 (68.7) | NA |
| Yes |
57 (27.0) |
NA |
| Exposure to swine | ||
| Only until 1997 | 26 | NA |
| Only until 2007 | 59 | NA |
| Until time of collection | 152 | NA |
*NA, not available.
†Sampled in July 2009.
‡Sampled in December 2008.
§Mean (median) age 48.2 (48) years for swine workers, 47.6 (47.2) years for controls.
¶Veterinarian, butcher, hunter.
