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. Author manuscript; available in PMC: 2009 Sep 12.
Published in final edited form as: Vaccine. 2008 Jun 17;26(Suppl 4):D5–D9. doi: 10.1016/j.vaccine.2008.05.076

Table 4.

Efficacy and Effectiveness of Inactivated Influenza Virus Vaccines

Age Group Study Type (Ref) N Percent Reduction
Adults Efficacy (R,DB,PC)a (14) ~2000/yr (~80% adult) Culture pos illness
   A/H1N1 yrs 79,74
   A/H3N2 yrs 71,79
Seroconversion
   A/H1N1 yrs 55,79
   A/H3N2 yrs 71.75
Effectiveness (R,DB,PC)a (15) 849 URIb 25
URI Absenteeism 43
URI Physician Visits 44
Elderly Efficacy (R,PC)a (8) 1838 Influenza & Seroconversion 58
Effectiveness (database source) (16) 713, 872 (person seasons over 10 yrs) P-I Hospitalizations 27
All Causes Deaths 48
Children Efficacyc (11) 1325 Influenza A or B infection or illness 63
a

R = randomized, DB = double blind, PC = placebo controlled

b

URI = Upper respiratory illness

c

Mean of five studies for <9 years