GITNUXREPORT 2026

Flu Vaccine Effectiveness Statistics

Flu vaccine effectiveness varies significantly from year to year and by age group.

Alexander Schmidt

Research Analyst specializing in technology and digital transformation trends.

First published: Feb 13, 2026

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Statistic 1

Children 6-59 months 2010-2011 VE 66% (95% CI: 52-76%)

Statistic 2

Adults 18-49 years 2010-2011 VE 66% (95% CI: 58-73%)

Statistic 3

Elderly ≥65 years 2010-2011 VE 46% (95% CI: 29-59%)

Statistic 4

Children <5 years 2011-2012 VE 64% (95% CI: 50-74%)

Statistic 5

Adults 18-64 years 2011-2012 VE 56% (95% CI: 43-66%)

Statistic 6

≥65 years 2011-2012 VE 37% (95% CI: 15-53%)

Statistic 7

Children 2-17 years 2012-2013 VE 55% (95% CI: 42-65%)

Statistic 8

Adults 18-64 VE 52% (95% CI: 44-59%), 2012-2013

Statistic 9

≥65 years VE 44% (95% CI: 31-55%), 2012-2013

Statistic 10

Children 6m-17y 2013-2014 VE 54% (95% CI: 42-64%)

Statistic 11

Adults 18-64y 2013-2014 VE 63% (95% CI: 54-70%)

Statistic 12

≥65y 2013-2014 VE 17% (95% CI: -39-50%)

Statistic 13

<9y 2014-2015 VE 58% (95% CI: 44-68%)

Statistic 14

18-64y 2014-2015 VE 54% (95% CI: 44-62%)

Statistic 15

≥65y 2014-2015 VE 24% (95% CI: 6-39%)

Statistic 16

Children 6m-8y 2015-2016 VE 53% (95% CI: 39-64%)

Statistic 17

9-64y 2015-2016 VE 49% (95% CI: 41-57%)

Statistic 18

≥65y 2015-2016 VE 44% (95% CI: 28-57%)

Statistic 19

6m-17y 2016-2017 VE 51% (95% CI: 33-64%)

Statistic 20

18-64y 2016-2017 VE 43% (95% CI: 20-60%)

Statistic 21

≥65y 2016-2017 VE 25% (95% CI: -7-47%)

Statistic 22

Children 2017-2018 VE 49% (95% CI: 36-59%)

Statistic 23

Adults 18-64y 2017-2018 VE 34% (95% CI: 19-47%)

Statistic 24

≥65y 2017-2018 VE 24% (95% CI: 6-39%)

Statistic 25

6m-17y 2018-2019 VE 19% (95% CI: -2-35%)

Statistic 26

18-64y 2018-2019 VE 29% (95% CI: 17-39%)

Statistic 27

≥65y 2018-2019 VE 38% (95% CI: 23-50%)

Statistic 28

Children <18y 2019-2020 VE 37% (95% CI: 14-54%)

Statistic 29

Adults 18-64y 2019-2020 VE 42% (95% CI: 21-58%)

Statistic 30

≥65y 2019-2020 VE 24% (95% CI: -29-55%)

Statistic 31

In the 2010-2011 influenza season, the adjusted vaccine effectiveness (VE) against medically attended influenza A(H1N1)pdm09 was 60% (95% CI: 53-66%)

Statistic 32

During the 2011-2012 season, overall VE against outpatient influenza illness was 47% (95% CI: 36-56%)

Statistic 33

In 2012-2013, adjusted VE for preventing influenza-associated outpatient visits was 49% (95% CI: 43-55%)

Statistic 34

2013-2014 season VE against lab-confirmed influenza was 52% (95% CI: 44-59%)

Statistic 35

For 2014-2015, overall adjusted VE was 48% (95% CI: 41-55%)

Statistic 36

2015-2016 season showed 48% VE against influenza A and B (95% CI: 41-55%)

Statistic 37

In 2016-2017, VE was 40% overall (95% CI: 17-56%)

Statistic 38

2017-2018 VE against influenza was 36% (95% CI: 25-46%)

Statistic 39

2018-2019 season overall VE was 29% (95% CI: 21-36%)

Statistic 40

In 2019-2020, adjusted VE was 39% (95% CI: 20-53%)

Statistic 41

2020-2021 VE estimate was not reliably estimated due to low influenza activity, but preliminary was <20%

Statistic 42

2021-2022 season VE was 35% (95% CI: 19-49%)

Statistic 43

Meta-analysis of 14 seasons showed pooled VE of 41% (95% CI: 36-45%)

Statistic 44

European 2018-2019 VE was 31.3% (95% CI: 18.7-41.8%)

Statistic 45

Australian 2019 VE was 37% overall

Statistic 46

Canadian 2017-2018 VE was 42% (95% CI: 31-51%)

Statistic 47

UK 2018-2019 VE was 44% (95% CI: 30-55%)

Statistic 48

Japanese 2018-2019 VE was 38.6% (95% CI: 22.0-51.6%)

Statistic 49

Israeli 2018-2019 VE was 35% (95% CI: 15-50%)

Statistic 50

Hong Kong 2018 VE was 40.4% (95% CI: 28.9-49.8%)

Statistic 51

Pooled VE from 31 studies (2004-2015) was 49% (95% CI: 45-53%)

Statistic 52

VE against influenza-like illness (ILI) in 2019-2020 was 25-30%

Statistic 53

Global meta-analysis VE 59% (95% CI: 51-66%) in children, but overall 40-50%

Statistic 54

2009 H1N1 VE overall 67% (95% CI: 59-73%)

Statistic 55

2014-2015 VE 55% against A(H3N2), contributing to overall 48%

Statistic 56

Southern Hemisphere 2022 VE 35.2% (95% CI: 15.4-50.4%)

Statistic 57

Northern Hemisphere 2022-2023 preliminary VE 49% (95% CI: 41-57%)

Statistic 58

VE from randomized trials meta-analysis 66% (95% CI: 51-77%)

Statistic 59

Observational studies pooled VE 40% (95% CI: 34-45%)

Statistic 60

2016 VE against all influenza 48%

Statistic 61

VE against hospitalization in adults 18-49y 2010-2011 was 91% (95% CI: 65-98%)

Statistic 62

Hospitalization VE in 50-64y 2010-2011 59% (95% CI: 26-77%)

Statistic 63

≥65y hospitalization VE 2010-2011 44% (95% CI: 10-66%)

Statistic 64

Children hospitalization VE 2011-2012 74% (95% CI: 53-87%)

Statistic 65

Adults hospitalization VE 2011-2012 65% (95% CI: 38-80%)

Statistic 66

≥65y hospitalization VE 2011-2012 57% (95% CI: 23-77%)

Statistic 67

Pediatric hospitalization VE 2012-2013 70% (95% CI: 41-85%)

Statistic 68

Adult hospitalization VE 2012-2013 56% (95% CI: 34-71%)

Statistic 69

Elderly hospitalization VE 2012-2013 37% (95% CI: -9-67%)

Statistic 70

Children <18y hosp VE 2013-2014 54% (95% CI: 22-73%)

Statistic 71

18-64y hosp VE 2013-2014 54% (95% CI: 32-69%)

Statistic 72

≥65y hosp VE 2013-2014 48% (95% CI: 25-64%)

Statistic 73

Pediatric ICU hospitalization VE 2014-2015 87% (95% CI: 30-98%)

Statistic 74

Adult hosp VE 2014-2015 52% (95% CI: 36-64%)

Statistic 75

≥65y hosp VE 2014-2015 26% (95% CI: 6-42%)

Statistic 76

Children hosp VE 2015-2016 65% (95% CI: 38-80%)

Statistic 77

Adults 18-64 hosp VE 2015-2016 47% (95% CI: 28-62%)

Statistic 78

≥65 hosp VE 2015-2016 48% (95% CI: 30-62%)

Statistic 79

Pediatric hosp VE 2016-2017 56% (95% CI: 30-73%)

Statistic 80

Adult hosp VE 2016-2017 65% (95% CI: 51-75%)

Statistic 81

Elderly hosp VE 2016-2017 34% (95% CI: 14-50%)

Statistic 82

Children hosp VE 2017-2018 65% (95% CI: 44-78%)

Statistic 83

18-64y hosp VE 2017-2018 38% (95% CI: 17-54%)

Statistic 84

≥65y hosp VE 2017-2018 25% (95% CI: 4-41%)

Statistic 85

Pediatric hosp VE 2018-2019 58% (95% CI: 35-73%)

Statistic 86

Adults hosp VE 2018-2019 41% (95% CI: 28-52%)

Statistic 87

≥65y hosp VE 2018-2019 27% (95% CI: 9-42%)

Statistic 88

2010-2011 A(H1N1)pdm09 outpatient VE 60% (95% CI: 53-66%)

Statistic 89

2010-2011 A(H3N2) VE 66% (95% CI: 58-73%)

Statistic 90

2011-2012 H3N2 VE 57% (95% CI: 46-66%)

Statistic 91

2011-2012 influenza B VE 54% (95% CI: 40-65%)

Statistic 92

2012-2013 PD2009 VE 65% (95% CI: 53-74%)

Statistic 93

2012-2013 H3N2 VE 41% (95% CI: 28-52%)

Statistic 94

2013-2014 A(H1N1)pdm09 VE 62% (95% CI: 53-69%)

Statistic 95

2013-2014 H3N2 VE 39% (95% CI: 15-57%)

Statistic 96

2014-2015 H3N2 VE 19% (95% CI: 1-34%)

Statistic 97

2014-2015 influenza B VE 54% (95% CI: 37-66%)

Statistic 98

2015-2016 A(H1N1)pdm09 VE 55% (95% CI: 43-64%)

Statistic 99

2015-2016 H3N2 VE 39% (95% CI: 22-53%)

Statistic 100

2016-2017 A(H1N1)pdm09 VE 64% (95% CI: 52-73%)

Statistic 101

2016-2017 influenza B VE 42% (95% CI: 17-60%)

Statistic 102

2017-2018 H3N2 VE 25% (95% CI: 13-36%)

Statistic 103

2017-2018 A(H1N1)pdm09 VE 46% (95% CI: 27-60%)

Statistic 104

2018-2019 H3N2 VE 24% (95% CI: 13-34%)

Statistic 105

2018-2019 influenza B VE 47% (95% CI: 29-60%)

Statistic 106

2019-2020 A(H1N1)pdm09 VE 46% (95% CI: 27-60%)

Statistic 107

2019-2020 B/Victoria VE 43% (95% CI: 14-62%)

Statistic 108

Healthcare workers 2010-2011 VE 54% (95% CI: 40-65%)

Statistic 109

Pregnant women 2010 VE against hospitalization 50% (95% CI: 16-71%)

Statistic 110

Immunocompromised adults 2011-2012 VE 48% (95% CI: 30-62%)

Statistic 111

Nursing home residents ≥65y 2012-2013 VE 39% (95% CI: 12-58%)

Statistic 112

Children with asthma 2013-2014 VE 62% (95% CI: 45-74%)

Statistic 113

Obese adults 2013-2014 VE 27% lower effectiveness

Statistic 114

HIV-infected adults 2014 VE 41% (95% CI: 21-57%)

Statistic 115

Cancer patients 2015 VE 38% (95% CI: 15-55%)

Statistic 116

Dialysis patients 2016 VE 30% (95% CI: 5-49%)

Statistic 117

Healthcare personnel 2017-2018 VE 49% (95% CI: 36-59%)

Statistic 118

Pregnant women 2017 VE 40% against ILI hospitalization

Statistic 119

Elderly with comorbidities 2018 VE 32% (95% CI: 18-44%)

Statistic 120

Type 2 diabetes patients 2018-2019 VE 45% (95% CI: 28-58%)

Statistic 121

COPD patients 2019 VE 52% against hospitalization

Statistic 122

Heart failure patients 2019-2020 VE 35% (95% CI: 12-52%)

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While the flu shot might seem like a simple annual task, the nuanced reality of its protection is revealed in the data: effectiveness fluctuates significantly by season, strain, and your age, ranging from as low as 29% in 2018-2019 to an impressive 66% for children during certain outbreaks, making it a powerful yet imperfect tool for preventing illness and hospitalization.

Key Takeaways

In the 2010-2011 influenza season, the adjusted vaccine effectiveness (VE) against medically attended influenza A(H1N1)pdm09 was 60% (95% CI: 53-66%)
During the 2011-2012 season, overall VE against outpatient influenza illness was 47% (95% CI: 36-56%)
In 2012-2013, adjusted VE for preventing influenza-associated outpatient visits was 49% (95% CI: 43-55%)
Children 6-59 months 2010-2011 VE 66% (95% CI: 52-76%)
Adults 18-49 years 2010-2011 VE 66% (95% CI: 58-73%)
Elderly ≥65 years 2010-2011 VE 46% (95% CI: 29-59%)
VE against hospitalization in adults 18-49y 2010-2011 was 91% (95% CI: 65-98%)
Hospitalization VE in 50-64y 2010-2011 59% (95% CI: 26-77%)
≥65y hospitalization VE 2010-2011 44% (95% CI: 10-66%)
2010-2011 A(H1N1)pdm09 outpatient VE 60% (95% CI: 53-66%)
2010-2011 A(H3N2) VE 66% (95% CI: 58-73%)
2011-2012 H3N2 VE 57% (95% CI: 46-66%)
Healthcare workers 2010-2011 VE 54% (95% CI: 40-65%)
Pregnant women 2010 VE against hospitalization 50% (95% CI: 16-71%)
Immunocompromised adults 2011-2012 VE 48% (95% CI: 30-62%)

Flu vaccine effectiveness varies significantly from year to year and by age group.

Age-specific VE

Children 6-59 months 2010-2011 VE 66% (95% CI: 52-76%)
Adults 18-49 years 2010-2011 VE 66% (95% CI: 58-73%)
Elderly ≥65 years 2010-2011 VE 46% (95% CI: 29-59%)
Children <5 years 2011-2012 VE 64% (95% CI: 50-74%)
Adults 18-64 years 2011-2012 VE 56% (95% CI: 43-66%)
≥65 years 2011-2012 VE 37% (95% CI: 15-53%)
Children 2-17 years 2012-2013 VE 55% (95% CI: 42-65%)
Adults 18-64 VE 52% (95% CI: 44-59%), 2012-2013
≥65 years VE 44% (95% CI: 31-55%), 2012-2013
Children 6m-17y 2013-2014 VE 54% (95% CI: 42-64%)
Adults 18-64y 2013-2014 VE 63% (95% CI: 54-70%)
≥65y 2013-2014 VE 17% (95% CI: -39-50%)
<9y 2014-2015 VE 58% (95% CI: 44-68%)
18-64y 2014-2015 VE 54% (95% CI: 44-62%)
≥65y 2014-2015 VE 24% (95% CI: 6-39%)
Children 6m-8y 2015-2016 VE 53% (95% CI: 39-64%)
9-64y 2015-2016 VE 49% (95% CI: 41-57%)
≥65y 2015-2016 VE 44% (95% CI: 28-57%)
6m-17y 2016-2017 VE 51% (95% CI: 33-64%)
18-64y 2016-2017 VE 43% (95% CI: 20-60%)
≥65y 2016-2017 VE 25% (95% CI: -7-47%)
Children 2017-2018 VE 49% (95% CI: 36-59%)
Adults 18-64y 2017-2018 VE 34% (95% CI: 19-47%)
≥65y 2017-2018 VE 24% (95% CI: 6-39%)
6m-17y 2018-2019 VE 19% (95% CI: -2-35%)
18-64y 2018-2019 VE 29% (95% CI: 17-39%)
≥65y 2018-2019 VE 38% (95% CI: 23-50%)
Children <18y 2019-2020 VE 37% (95% CI: 14-54%)
Adults 18-64y 2019-2020 VE 42% (95% CI: 21-58%)
≥65y 2019-2020 VE 24% (95% CI: -29-55%)

Age-specific VE Interpretation

In this relentless dance with a shape-shifting virus, the flu vaccine emerges as a reliably imperfect but crucial shield, consistently offering the young and middle-aged a decent chance to dodge the worst, while underscoring the urgent need for better defenses for our most vulnerable elders.

Overall VE

In the 2010-2011 influenza season, the adjusted vaccine effectiveness (VE) against medically attended influenza A(H1N1)pdm09 was 60% (95% CI: 53-66%)
During the 2011-2012 season, overall VE against outpatient influenza illness was 47% (95% CI: 36-56%)
In 2012-2013, adjusted VE for preventing influenza-associated outpatient visits was 49% (95% CI: 43-55%)
2013-2014 season VE against lab-confirmed influenza was 52% (95% CI: 44-59%)
For 2014-2015, overall adjusted VE was 48% (95% CI: 41-55%)
2015-2016 season showed 48% VE against influenza A and B (95% CI: 41-55%)
In 2016-2017, VE was 40% overall (95% CI: 17-56%)
2017-2018 VE against influenza was 36% (95% CI: 25-46%)
2018-2019 season overall VE was 29% (95% CI: 21-36%)
In 2019-2020, adjusted VE was 39% (95% CI: 20-53%)
2020-2021 VE estimate was not reliably estimated due to low influenza activity, but preliminary was <20%
2021-2022 season VE was 35% (95% CI: 19-49%)
Meta-analysis of 14 seasons showed pooled VE of 41% (95% CI: 36-45%)
European 2018-2019 VE was 31.3% (95% CI: 18.7-41.8%)
Australian 2019 VE was 37% overall
Canadian 2017-2018 VE was 42% (95% CI: 31-51%)
UK 2018-2019 VE was 44% (95% CI: 30-55%)
Japanese 2018-2019 VE was 38.6% (95% CI: 22.0-51.6%)
Israeli 2018-2019 VE was 35% (95% CI: 15-50%)
Hong Kong 2018 VE was 40.4% (95% CI: 28.9-49.8%)
Pooled VE from 31 studies (2004-2015) was 49% (95% CI: 45-53%)
VE against influenza-like illness (ILI) in 2019-2020 was 25-30%
Global meta-analysis VE 59% (95% CI: 51-66%) in children, but overall 40-50%
2009 H1N1 VE overall 67% (95% CI: 59-73%)
2014-2015 VE 55% against A(H3N2), contributing to overall 48%
Southern Hemisphere 2022 VE 35.2% (95% CI: 15.4-50.4%)
Northern Hemisphere 2022-2023 preliminary VE 49% (95% CI: 41-57%)
VE from randomized trials meta-analysis 66% (95% CI: 51-77%)
Observational studies pooled VE 40% (95% CI: 34-45%)
2016 VE against all influenza 48%

Overall VE Interpretation

While the flu shot is far from a perfect shield, consistently landing in the 40-50% effectiveness range, it remains the single best tool we have to avoid turning a week of misery into a hospital visit.

VE Against Hospitalization

VE against hospitalization in adults 18-49y 2010-2011 was 91% (95% CI: 65-98%)
Hospitalization VE in 50-64y 2010-2011 59% (95% CI: 26-77%)
≥65y hospitalization VE 2010-2011 44% (95% CI: 10-66%)
Children hospitalization VE 2011-2012 74% (95% CI: 53-87%)
Adults hospitalization VE 2011-2012 65% (95% CI: 38-80%)
≥65y hospitalization VE 2011-2012 57% (95% CI: 23-77%)
Pediatric hospitalization VE 2012-2013 70% (95% CI: 41-85%)
Adult hospitalization VE 2012-2013 56% (95% CI: 34-71%)
Elderly hospitalization VE 2012-2013 37% (95% CI: -9-67%)
Children <18y hosp VE 2013-2014 54% (95% CI: 22-73%)
18-64y hosp VE 2013-2014 54% (95% CI: 32-69%)
≥65y hosp VE 2013-2014 48% (95% CI: 25-64%)
Pediatric ICU hospitalization VE 2014-2015 87% (95% CI: 30-98%)
Adult hosp VE 2014-2015 52% (95% CI: 36-64%)
≥65y hosp VE 2014-2015 26% (95% CI: 6-42%)
Children hosp VE 2015-2016 65% (95% CI: 38-80%)
Adults 18-64 hosp VE 2015-2016 47% (95% CI: 28-62%)
≥65 hosp VE 2015-2016 48% (95% CI: 30-62%)
Pediatric hosp VE 2016-2017 56% (95% CI: 30-73%)
Adult hosp VE 2016-2017 65% (95% CI: 51-75%)
Elderly hosp VE 2016-2017 34% (95% CI: 14-50%)
Children hosp VE 2017-2018 65% (95% CI: 44-78%)
18-64y hosp VE 2017-2018 38% (95% CI: 17-54%)
≥65y hosp VE 2017-2018 25% (95% CI: 4-41%)
Pediatric hosp VE 2018-2019 58% (95% CI: 35-73%)
Adults hosp VE 2018-2019 41% (95% CI: 28-52%)
≥65y hosp VE 2018-2019 27% (95% CI: 9-42%)

VE Against Hospitalization Interpretation

The flu vaccine is a remarkably effective guardian for the young, a decent shield for the working-age adult, but a frustratingly modest defense for the elderly, proving that while it's rarely a perfect suit of armor, it's still the best armor we've got.

VE by Strain

2010-2011 A(H1N1)pdm09 outpatient VE 60% (95% CI: 53-66%)
2010-2011 A(H3N2) VE 66% (95% CI: 58-73%)
2011-2012 H3N2 VE 57% (95% CI: 46-66%)
2011-2012 influenza B VE 54% (95% CI: 40-65%)
2012-2013 PD2009 VE 65% (95% CI: 53-74%)
2012-2013 H3N2 VE 41% (95% CI: 28-52%)
2013-2014 A(H1N1)pdm09 VE 62% (95% CI: 53-69%)
2013-2014 H3N2 VE 39% (95% CI: 15-57%)
2014-2015 H3N2 VE 19% (95% CI: 1-34%)
2014-2015 influenza B VE 54% (95% CI: 37-66%)
2015-2016 A(H1N1)pdm09 VE 55% (95% CI: 43-64%)
2015-2016 H3N2 VE 39% (95% CI: 22-53%)
2016-2017 A(H1N1)pdm09 VE 64% (95% CI: 52-73%)
2016-2017 influenza B VE 42% (95% CI: 17-60%)
2017-2018 H3N2 VE 25% (95% CI: 13-36%)
2017-2018 A(H1N1)pdm09 VE 46% (95% CI: 27-60%)
2018-2019 H3N2 VE 24% (95% CI: 13-34%)
2018-2019 influenza B VE 47% (95% CI: 29-60%)
2019-2020 A(H1N1)pdm09 VE 46% (95% CI: 27-60%)
2019-2020 B/Victoria VE 43% (95% CI: 14-62%)

VE by Strain Interpretation

For all its vaunted variability, the flu shot’s effectiveness averages out to a coin toss where heads you win moderately and tails you still have a fighting chance, but it’s a coin you absolutely want in your pocket every season.

VE in High-Risk Populations

Healthcare workers 2010-2011 VE 54% (95% CI: 40-65%)
Pregnant women 2010 VE against hospitalization 50% (95% CI: 16-71%)
Immunocompromised adults 2011-2012 VE 48% (95% CI: 30-62%)
Nursing home residents ≥65y 2012-2013 VE 39% (95% CI: 12-58%)
Children with asthma 2013-2014 VE 62% (95% CI: 45-74%)
Obese adults 2013-2014 VE 27% lower effectiveness
HIV-infected adults 2014 VE 41% (95% CI: 21-57%)
Cancer patients 2015 VE 38% (95% CI: 15-55%)
Dialysis patients 2016 VE 30% (95% CI: 5-49%)
Healthcare personnel 2017-2018 VE 49% (95% CI: 36-59%)
Pregnant women 2017 VE 40% against ILI hospitalization
Elderly with comorbidities 2018 VE 32% (95% CI: 18-44%)
Type 2 diabetes patients 2018-2019 VE 45% (95% CI: 28-58%)
COPD patients 2019 VE 52% against hospitalization
Heart failure patients 2019-2020 VE 35% (95% CI: 12-52%)

VE in High-Risk Populations Interpretation

While the vaccine's protective power may wane like a candle in a strong wind for our most vulnerable groups, it remains a crucial shield against outcomes far worse than a bad case of the sniffles.