. 2011 Jun 10;47(12):857–862. doi: 10.1111/j.1440-1754.2011.02098.x

Table 2.

Number of ILI episodes and person‐time follow up, relative risk, and vaccine efficacy for ILI prevention in each age group

Age group	Vaccination status	Rate (ILI episodes/child‐weeks)	Relative rate (95% CI)
Age group	Vaccination status	Rate (ILI episodes/child‐weeks)	Vaccine efficacy estimate
6–23 months	Vaccinated	0.05 (4/78)	0.46 (0.15–1.45)
6–23 months	Controls	0.11 (14/126)	54%
24–59 months	Vaccinated	0.03 (11/403)	0.61 (0.30–1.22)
24–59 months	Controls	0.05 (30/666)	39%
Total	Vaccinated	0.03 (15/481)	0.56 (0.32–1.02)
Total	Controls	0.06 (44/792)	44%

CI, confidence interval; ILI, influenza‐like illness.