Table 1

Demographic characteristics of the study children.

Characteristics
PCV-7 group (n = 811)
Control group (n = 744)
P

Males (%)
476 (58.7)
413 (55.5)
0.22
Age at vaccination, median days (range)



     First dose
82 (75–104)
82 (76–103)
0.96
     Second dose
140 (128–155)
143 (130–158)
0.93
     Third dose
340 (328–361)
343 (331–364)
0.92
Breast-feeding for at least three months, No. (%)
551 (67.9)
476 (64.1)
0.11
Living in urban area, No. (%)
527 (65.0)
498 (66.9)
0.44
Mother's age, median years (range)
33 (24–49)
33 (20–46)
0.96
Father's age, median years (range)
35 (21–50)
35 (21–51)
0.99
No. of persons in household, median (range)
3 (2–4)
3 (2–4)
1.00
No. of siblings, median (range)
1 (0–2)
1 (0–2)
1.00
Children with a smoker in the family, No. (%)
194 (23.9)
182 (24.5)
0.84
Children attending day-care, No. (%)
284 (35.0)
231 (31.0)
0.10
Duration of day care attendance, No. (%)



     0–6 months
79 (9.7)
65 (8.7)
0.55
     7–12 months
33 (4.1)
44 (5.9)
0.11
     13–18 months
111 (13.7)
94 (12.6)
0.59
     19–24 months
78 (9.6)
58 (7.8)
0.23
Vaccinated against influenza, No. (%)
12 (1.5)
10 (1.3)
0.99

No significant between-group differences.

Esposito et al. Respiratory Research 2007 8:12   doi:10.1186/1465-9921-8-12