Table 1.

Baseline vaccine effectiveness and efficacy of TIV with upper and lower limits, by target group

Vaccination target group	Baseline vaccine effectiveness (%)	Lower limit of vaccine effectiveness (%)	Upper limit of vaccine effectiveness (%)	Baseline vaccine efficacy (%)	Lower limit of vaccine efficacy (%)	Upper limit of vaccine efficacy (%)	RCTs used for efficacy
6 – 23 months	59 [30]	19.4 [32]	65.7 [31]	45 [33]	25	65	2 studies, 786 recruits (525 vaccinated 261 placebo)
Healthy, 2–64 years (health care workers and pregnant women)	51 [30]	41.3 [31]	63.3 [32]	61 [34]	48	70	17 studies 31,325 recruits (16,213 vaccinated 15,112 placebo)
Underlying chronic conditions, 2–64 yrs	51 [30]	41.3 [31]	63.3 [32]	61 [34]	48	70	17 studies 31,325 recruits (16,213 vaccinated 15,112 placebo)
Elderly	39 [30]	15.1 [32]	59.9 [31]	58 [35]	34	73	3 studies, 2217 recruits (1,110 vaccinated 1,107 placebo)