Table 1.

Demographic, Clinical, and Vaccination Details of Pandemic (H1N1) 2009 Cases and Controls

Variable	No. of cases (Total =933)	%	No. of controls (Total=1220)	%
Received pandemic vaccine
1st dose ≥14 days before estimated onset	21	2.3	45	3.7
1st dose 7–13 days before estimated onset	10	1.1	24	2.0
1st dose <7 days before estimated onset	39	4.2	39	3.2
2nd dose ≥14 days before estimated onset	0	0.0	5	0.4
2nd dose 7–13 days before estimated onset	0	0.0	2	0.2
Unvaccinated	756	81.0	938	76.9
Vaccination status unknown	107	11.5	167	13.7
Received seasonal vaccine
Vaccinated ≥14 days before Estimated onset	220	23.6	294	24.1
Vaccinated 7–13 days before estimated onset	24	2.6	35	2.9
Vaccinated <7 days before estimated onset	18	1.9	34	2.8
Unvaccinated	559	59.9	696	57.1
Vaccination status unknown	112	12.0	161	13.2
Sex and Pregnancy
Female – not pregnant	396	42.4	533	43.7
Female – pregnant	130	13.9	53	4.3
Female – pregnant unknown	4	0.4	15	1.2
Male	403	43.2	619	50.7
Age group (years)
<5	123	13.2	203	16.6
5–9	110	11.8	126	10.3
10–14	85	9.1	66	5.4
15–24	120	12.9	135	11.1
25–34	146	15.7	130	10.7
35–49	152	16.3	198	16.2
50–64	146	15.7	216	17.7
65+	51	5.5	146	12.0
Interval (days between onset and sample collection)
0–1	220	23.6	204	16.7
2–4	268	28.7	199	16.3
5–7	102	10.9	88	7.2
8–14	53	5.7	69	5.7
15–29	17	1.8	19	1.6
Not stated, interval estimated from date of swab or hospitalization	273	29.3	641	52.5
Hospitalized
No	159	17.0	263	21.6
Yes	669	71.7	728	59.7
Unknown	105	11.3	229	18.8
Risk factora
Chronic respiratory	151	16.2	272	22.3
Chronic heart	98	10.5	179	14.7
Chronic renal	64	6.9	112	9.2
Chronic liver	30	3.2	55	4.5
Chronic neurological	120	13.3	162	12.9
Diabetes	100	10.7	138	11.3
Immunosuppressant disease	118	12.7	259	21.2
Immunosuppressant treatment	139	14.9	268	22.0
Any asthma	403	43.2	429	35.1
Severe asthma	242	25.9	259	21.2

NOTE. If symptom onset date was not stated, onset date is presume to be date of hospitalization or 3 days before date of swab was taken.

^aNote that individuals may have multiple risk factors.