Past Seasons Vaccine Effectiveness Estimates

These pages includes information about the estimated seasonal influenza vaccine effectiveness from past seasons, including tables of the estimated vaccine effectiveness (and 95% credible interval [Cr I]) by age group and virus subtype. Information on how these estimates are calculated can be found on CDC’s web page How CDC Estimates vaccine efficacy and effectiveness.

Table. Adjusted vaccine effectiveness estimates for influenza seasons from 2004-2018

CDC calculates vaccine effectiveness estimates through the U.S. VE Network

Table. Adjusted vaccine effectiveness estimates for influenza seasons from 2004-2018CDC calculates vaccine effectiveness estimates through the U.S. VE Network

Influenza Season

Reference

Study Site(s)

No. of Patients

Adjusted Overall VE (%)

95% CI

2018-19*

Doyle 2019 WI, MI, PA, TX, WA 3,254

47*

34, 57

2017-18

Rolfes 2019External WI, MI, PA, TX, WA 8,436

38

31, 43

2016-17

Unpublished final estimates. WI, MI, PA, TX, WA 7410

40

32, 46

2015-16

Jackson 2017External

WI, MI, PA, TX, WA

6879

48

41, 55

2014-15

Zimmerman 2016External

WI, MI, PA, TX, WA

9311

19

10, 27

2013-14

Gaglani 2016External

WI, MI, PA, TX, WA

5999

52

44, 59

2012-13

McLean 2014External

WI, MI, PA, TX, WA

6452

49

43, 55

2011-12

Ohmit 2014External

WI, MI, PA, TX, WA

4771

47

36, 56

2010-11

Treanor 2011External

WI, MI, NY, TN

4757

60

53, 66

2009-10

Griffin 2011External

WI, MI, NY, TN

6757

56

23, 75

2008-09

Unpublished

WI, MI, NY, TN

6713

41

30, 50

2007-08

Belongia 2011External

WI

1914

37

22, 49

2006-07

Belongia 2009External

WI

871

52

22, 70

2005-06

Belongia 2009External

WI

346

21

-52, 59

2004-05

Belongia 2009External

WI

762

10

-36, 40

* Vaccine effectiveness estimates for 2018-2019 are preliminary estimates and will be updated with final estimates at the end of the 2018-2019 U.S. influenza season.
* From 2004-05 through 2010-11, the Network also enrolled inpatients.
† Vaccine effectiveness (VE) estimates for the 2008-2009 flu season have not yet been published.
‡ Number of patients used in VE calculation.