Table 2.

Descriptive Characteristics of Enrolled Patients With Medically Attended Acute Respiratory Infections by Vaccination Status

Characteristics	Vaccinateda		Unvaccinated		P Value
	N = 2275	%	N = 2482	%
Study community
Marshfield, WI	870	38	884	36	<.001
Rochester, NY	237	10	258	10
Southeast, MI	505	22	736	30
Nashville, TN	663	29	604	24
Enrollment site
Outpatient	1670	73	1728	70	<.001
Inpatient	373	16	373	15
Emergency Dept	232	10	381	15
Sex
Male	1000	44	1151	46	.05
Female	1275	56	1331	54
Age groups
6 months–8 yearsb	1029	45	793	32	<.001
9–49 years	638	28	1273	51
≥50 years	608	27	416	17
Race
White	1586	70	1583	64	<.001
Black	350	15	559	23
Other	339	15	340	14
Insurance status
Not insured	50	2	237	10	<.001
Private insurance	1493	66	1633	66
Public insurance	732	32	612	25
High-risk condition
No	1297	57	1735	70	<.001
Yes	978	43	747	30
Onset to test
<3 days	985	43	1088	44	.42
3–4 days	825	36	885	36
5–7 days	465	20	509	21
Influenza test
Negative	1958	86	1759	71	<.001
Positive	317	14	723	29
Influenza A	212c	9	498d	20	<.001
Influenza B	105	5	228d	9	<.001
Influenza H1N1	94	4	279	11	<.001
Influenza H3N2	115	5	219	9	<.001

^a Vaccinated subjects are defined by last dose of the vaccine received ≥14 days before symptom onset.

^b Partially or fully immunized.

^c Three influenza A were unsubtyped.

^d Three unvaccinated subjects were coinfected with both influenza A and B.