Table 2.
Comparison of pH1N1-positive cases with matched hospital controls and test-negative controls, respectively: Analysis of vaccination status, underlying illness and other potential risk factors
| |
pH1N1 positive casesvs.matched hospital controls |
pH1N1 positive casesvs.pH1N1 negative controls |
||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Variable |
Cases (23) |
Controls (40) |
MOR* (95% CI) |
p |
Cases (24) |
Controls (119) |
Exact OR (95% CI)** |
p |
||||
| N | % | N | % | N | % | N | ||||||
|
Pandemic influenza vaccination 2009/10 |
23 |
0 |
40 |
15 |
0.2 (0–1.5) |
0.13 |
24 |
0 |
117 |
6 |
0.5 (0–4.8) |
0.62 |
|
Seasonal influenza vaccination 2009/10 |
23 |
26 |
39 |
23 |
1.3 (0.2-7.5) |
0.99 |
24 |
25 |
117 |
31 |
0.8 (0.2-2.8) |
0.95 |
|
Seasonal influenza vaccination 2008/09 |
23 |
26 |
40 |
25 |
1.1 (0.3-4.1) |
1.0 |
24 |
25 |
111 |
19 |
3.4 (0.6-20.8) |
0.21 |
|
Seasonal influenza vaccination 2007/08 |
23 |
22 |
40 |
20 |
1.2 (0.2-7.6) |
1.00 |
24 |
21 |
110 |
16 |
2.4 (0.4-14.9) |
0.45 |
|
Pneumococcal vaccine |
20 |
20 |
35 |
11 |
2.3 (0.4-15.9) |
0.49 |
21 |
24 |
103 |
13 |
3.4 (0.6-19.5) |
0.19 |
|
Pandemic vaccine offered by employer |
23 |
9 |
40 |
30 |
0.1 (0–1.1) |
0.07 |
24 |
8 |
115 |
12 |
1.1 (0.1-6.7) |
1.00 |
|
Any chronic underlying illness |
23 |
70 |
40 |
63 |
1.7 (0.1-117.7) |
1.0 |
24 |
67 |
119 |
66 |
1.5 (0.4-6.3) |
0.72 |
|
Any chronic lung disease |
23 |
43 |
40 |
23 |
2.2 (0.6-8.6) |
0.27 |
24 |
42 |
118 |
34 |
2.2 (0.6-7.9) |
0.25 |
|
COPD |
23 |
22 |
40 |
3 |
7.9 (1.0-∞) |
0.06 |
24 |
21 |
118 |
27 |
1.2 (0.3-5.2) |
0.99 |
|
Asthma |
23 |
26 |
40 |
15 |
1.8 (0.4-8.9) |
0.58 |
24 |
25 |
118 |
16 |
1.4 (0.3-5.5) |
0.77 |
|
Chronic bronchitis |
23 |
13 |
40 |
5 |
3.2 (0.2-177.0) |
0.61 |
24 |
13 |
118 |
17 |
0.9 (0.1-4.5) |
1.00 |
|
Cardiovascular disease |
23 |
39 |
40 |
28 |
2.6 (0.4-29.2) |
0.44 |
24 |
38 |
119 |
40 |
1.4 (0.3-5.6) |
0.84 |
|
Immunosuppression |
21 |
14 |
40 |
0 |
7.7 (0.8-∞) |
0.07 |
22 |
14 |
116 |
15 |
1.1 (0.2-5.5) |
1.00 |
|
BMI ≥31 |
23 |
30 |
39 |
8 |
5.1 (0.9-51.2) |
0.06 |
24 |
29 |
118 |
17 |
2.3 (0.6-9.1) |
0.27 |
|
Frailty |
23 |
4 |
40 |
3 |
1.4 (0–117.7) |
1.00 |
24 |
4 |
118 |
9 |
0.4 (0.1-3.4) |
0.65 |
|
≥ 1 physician visits in past year |
23 |
70 |
39 |
72† |
1.0 (0.3-3.3) |
1.00 |
24 |
67 |
118 |
73† |
1.7 (0.5-6.6) |
0.54 |
|
≥ 3 physician visits in past year |
23 |
48 |
39 |
38‡ |
1.5 (0.4-4.9) |
0.64 |
24 |
46 |
118 |
53‡ |
1.3 (0.4-4.2) |
0.84 |
|
≥ 1 hospitalization in past year |
23 |
17 |
39 |
49 |
0.2 (0–0.7) |
0.01 |
24 |
17 |
119 |
32 |
0.4 (0.1-1.6) |
0.26 |
|
Current smoker |
23 |
61 |
40 |
53 |
1.3 (0.4-3.8) |
0.81 |
24 |
58 |
119 |
40 |
1.6 (0.5-4.8) |
0.53 |
|
>20 packyears vs. non-smoker |
23 |
30 |
40 |
25 |
1.8 (0.4-11.1) |
0.69 |
24 |
29 |
119 |
33 |
2.2 (0.4-14.4) |
0.52 |
|
Alcohol: ≥ 1 drink/week |
23 |
43 |
40 |
65 |
0.3 (0.1-1.1) |
0.08 |
24 |
45 |
117 |
56 |
0.6 (0.2-1.8) |
0.40 |
|
Children in household |
23 |
39 |
40 |
15 |
4.3 (1.0-26.0) |
0.04 |
24 |
38 |
119 |
36 |
1.0 (0.3-3.0) |
1.00 |
|
Public transport (> = 3x/week) vs. none |
23 |
30 |
40 |
58 |
0.2 (0–1.1) |
0.06 |
24 |
29 |
119 |
45 |
0.3 (0.1-1.0) |
0.06 |
|
Owns car |
23 |
74 |
40 |
45 |
3.3 (1.0-14.3) |
0.06 |
24 |
75 |
119 |
51 |
3.6 (1.1-13.9) |
0.04 |
|
Completion of at least Grade 10 |
23 |
68 |
40 |
77 |
0.6 (0.1-3.1) |
0.72 |
24 |
71 |
117 |
69 |
1.5 (0.5-5.4) |
0.66 |
| Private health insurance | 23 | 24 | 40 | 13 | 2.1 (0.2-26.2) | 0.74 | 24 | 25 | 119 | 17 | 1.2 (0.3-4.2) | 1.00 |
*MOR calculated with exact logistic regression. **Adjusted for time period and age.
Comparison of hospital and test-negative controls: †pχ2 = 0.11 ‡pχ2 = 0.90.