Post on 22-Dec-2015
Influenza
Timothy Wiemken, PhD MPH CICAssistant Professor
Division of Infectious DiseasesUniversity of Louisville
tim.wiemken@louisville.edu
Overview
• The influenza virus• Influenza transmission• Available Vaccines• Vaccine Efficacy/Effectiveness
The Influenza Virus
The Influenza Virus
Three types of influenza viruses
A
B
C
The Influenza Virus
Three types of influenza viruses
Influenza A Separated into serotypes using
Hemagglutinin and Neuraminidase
16 different H’s9 different N’s
Influenza A Strains
1918-19
Severe
1957-58
Severe
1968-69
Moderate
1977-78
Mild
2009- 12
H1N1
Mild
1918 1950 1960 1970 1980 2000 2009 2012
H2N2 H3N2 2009 H1N1
The Influenza Virus
2012-
H3N2
H1N1
Influenza A Strains
1918-19
Severe
1957-58
Severe
1968-69
Moderate
1977-78
Mild
2009- 12
H1N1
Mild
1918 1950 1960 1970 1980 2000 2009 2012
H2N2 H3N2 2009 H1N1
The Influenza Virus
2012-
H3N2
H1N1
Influenza A Strains
1918-19
Severe
1957-58
Severe
1968-69
Moderate
1977-78
Mild
2009- 12
H1N1
Mild
1918 1950 1960 1970 1980 2000 2009 2012
H2N2 H3N2 2009 H1N1
The Influenza Virus
2012-
H3N2
H1N1
Influenza A Strains
1918-19
Severe
1957-58
Severe
1968-69
Moderate
1977-78
Mild
2009- 12
H1N1
Mild
1918 1950 1960 1970 1980 2000 2009 2012
H2N2 H3N2 2009 H1N1
The Influenza Virus
2012-
H3N2
H1N1
Influenza A Strains
1918-19
Severe
1957-58
Severe
1968-69
Moderate
1977-78
Mild
2009- 12
H1N1
Mild
1918 1950 1960 1970 1980 2000 2009 2012
H2N2 H3N2 2009 H1N1
The Influenza Virus
2012-
H3N2
H1N1
The Influenza Virus
6 19 33
12984
190
321
431
686
1195
65
358
0
200
400
600
800
1000
1200
Age group (yrs)
Pe
r 1
00
,00
0 p
op
ula
tio
n
Influenza-related mortality Influenza-related hospitalizations
65-69 70-74 75-79 80-84 ≥8550-64
The Influenza Virus
Naming of influenza viruses
1. Antigenic type (A, B, C)2. Host of Origin (unless human)3. Geographical Origin4. Strain Number5. Year of Isolation6. For A’s, H and N antigens
The Influenza Virus
A/Perth/16/2009 (H3N2)
Influenza A
The Influenza Virus
A/Perth/16/2009 (H3N2)
Influenza A
No Host – Human!
The Influenza Virus
A/Perth/16/2009 (H3N2)
Influenza A
No Host – Human!
From Perth
The Influenza Virus
A/Perth/16/2009 (H3N2)
Influenza A
No Host – Human!
From Perth
16th strain
The Influenza Virus
A/Perth/16/2009 (H3N2)
Influenza A
No Host – Human!
From Perth
16th strain
First isolated in 2009
The Influenza Virus
A/Perth/16/2009 (H3N2)
Influenza A
No Host – Human!
From Perth
16th strain
First isolated in 2009
Since it is Flu A, need H and N type, H3N2
The Influenza Virus
• B’s are named the same but don’t have subtypes
• Lineages are Victoria or Yamagata
The Influenza Virus
Overview
• The influenza virus• Influenza transmission• Available Vaccines• Vaccine Efficacy/Effectiveness
Influenza Transmission
Droplet
Contact
Influenza Transmission
Overview
• The influenza virus• Influenza transmission• Available Vaccines• Vaccine Efficacy/Effectiveness
Available Vaccines
• Trivalent (2 A’s, 1 B) Intramuscular• Trivalent Intramuscular High Dose• Trivalent Intradermal• Quadrivalent (2A’s, 2 B’s)
Intramuscular• Quadrivalent Intranasal
Available Vaccines
• What should I use?• When should I use it?
Available Vaccines
• CDC says whatever.
Available Vaccines
• Kids/around kids = quadrivalent– Intranasal (quadrivalent)
• HCW = quadrivalent• Comorbidities = quadrivalent• ≥65 = high dose
Available Vaccines
• Kids/around kids = quadrivalent– Intranasal (quadrivalent)
• HCW = quadrivalent• Comorbidities = quadrivalent• ≥65 = high dose
In other words, don’t waste the quadrivalent on creepers.
Available Vaccines
Overview
• The influenza virus• Influenza transmission• Available Vaccines• Vaccine Efficacy/Effectiveness
Vaccine Efficacy/Effectiveness
Efficacy: Did it work in the clinical trial versus placebo?
Effectiveness: Does it work in real life?
The numbers vary based on the outcome under study.
Vaccine Efficacy/Effectiveness
• Trivalent (2 A’s, 1 B) Intramuscular
Vaccine Efficacy/Effectiveness
• Trivalent (2 A’s, 1 B) Intramuscular• Effectiveness for preventing ARI due
to Flu
Age Group Subtype Vaccine Effectiveness (95% CI)
Overall All 56% (47%-63%)
Overall H3N2 47% (35%-58%)
Overall B 67% (51%-78%)
Vaccine Efficacy/Effectiveness
• Trivalent (2 A’s, 1 B) Intramuscular• I heard it was 9% though?
Vaccine Efficacy/Effectiveness
• Trivalent (2 A’s, 1 B) Intramuscular• I heard it was 9% though?
• For H3N2 only… for those over 65…– Effectiveness 9%– 95% CI: -84% to 55%– ~200 people only!!!
Available Vaccines
Pop quiz
How effective is the flu vaccine if you don’t receive it?
Vaccine Efficacy/Effectiveness
Influenza B effectiveness… historicallySeason % B % Yamagata % Victoria Vaccine
2000–2001 46 100 0 Yamagata
2001–2002 13 23 77 Yamagata
2002–2003 43 0.4 99.6 Victoria
2003–2004 1 93 7 Victoria
2004–2005 25 74 26 Yamagata
2005–2006 19 22 78 Yamagata
2006–2007 21 24 77 Victoria
2007–2008 29 98 2 Victoria
2008–2009 33 17 83 Yamagata
2009–2010 0.2 12 88 Victoria
2010–2011 30 6 94 Victoria
2011–2012 14 51 49 Victoria
Vaccine Efficacy/Effectiveness
• Quadrivalent (2 A’s, 2 B) Intramuscular
Overview
• The influenza virus• Influenza transmission• Available Vaccines• Vaccine Efficacy/Effectiveness