Table 2

Frequency of respiratory tract infections (RTIs) during follow-up.

Episodes
PCV-7 group (n = 811)
Control group (n = 744)
RR
95% CI
P

Total number of RTIs during follow-up
3,877
3,460



Episodes/100 child-years
239.0
232.5
1.02
0.98–1.07
0.32
RTIs in children aged 6–12 months
1,035
928



Episodes/100 child-years
255.2
249.4
1.02
0.94–1.12
0.62
RTIs in children aged 13–18 months
1,185
986



Episodes/100 child-years
292.2
265.0
1.10
1.00–1.18
0.055
RTIs in children aged 19–24 months
998
872



Episodes/100 child-years
246.1
234.4
1.05
0.96–1.15
0.31
RTIs in children aged 25–30 months
659
674



Episodes/100 child-years
162.5
181.1
0.90
0.81–1.00
0.047

RR = relative risk; 95% CI = 95% confidence interval.

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