MVP est un partenariat entre l’OMS et PATH
Photos Benoît Lange
Introduction of a Men A conjugate vaccine: How will this change meningitis in Africa?
GEO Meningitis Environmental Risk Consultative MeetingGeneva, 26-27 September, 2007
F Marc LaForce, MD
Confidentiel MVP est un partenariat entre l’OMS et PATH
Country-Level Attack Rate - NIGER
0
10
20
30
40
50
60
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
Year
Cas
es/1
0000
0 p
op
ula
tio
n
Confidentiel MVP est un partenariat entre l’OMS et PATH
Outline of Presentation
1. How does Neisseria meningitidis spread in a population?
2. Can this spread be blocked by immunization?
3. Likely public health impact after the introduction of a Men A conjugate vaccine
4. What will not happen
Confidentiel MVP est un partenariat entre l’OMS et PATH
Flow of Neisseria meningitidis Through a Population
Invasion
Colonisation'Recovery'
Acquisition
Transmission
Release Disease
Invasion
Courtesy Drs. Maiden and McLennan
Courtesy Dr. Martin Maiden
Reservoir
Confidentiel MVP est un partenariat entre l’OMS et PATH
Why are conjugate vaccines different?
• In addition to providing individual protection against serious disease, they also reduce asymptomatic carriage
• Reduced carriage lower transmission indirect protection
even unvaccinated individuals in the population are at reduced risk of disease
Confidentiel MVP est un partenariat entre l’OMS et PATH
Invasion
Colonisation'Recovery'
Acquisition
Transmission
Release Disease
Invasion
X
?X
X
X
X
Population effects of MCC vaccinesPopulation effects of MCC vaccinesHerd immmunity or vaccine escapeHerd immmunity or vaccine escape
Courtesy Dr.Martin Maiden
Population Effects of Men C Conjugate Vaccines: The Development of Herd Immunity
reservoir
Confidentiel MVP est un partenariat entre l’OMS et PATH
Flow of colonization in a population where all are susceptible
Number of infectious cycles
Number colonized per infectious cycle
1 3 9 27 81
1 2 3 4 5
27 81
Confidentiel MVP est un partenariat entre l’OMS et PATH
Flow of colonization in a population where two thirds of the population are protected
1 1 1 1 1
1 2 3 4 5
Number of infectious cycles
Number colonized in each infectious cycle
Confidentiel MVP est un partenariat entre l’OMS et PATH
Impact of PNC-7 vaccination in USA
Source: MMWR weekly, 2005 / 54(36);893-897
Confidentiel MVP est un partenariat entre l’OMS et PATH
MenC vaccination in England & Wales
0100200300400500600700800900
1000
1998
/99
1999
/00
2000
/01
2001
/02
2002
/03
2003
/04
2004
/05
2005
/06
2006
/07
2007
/08
2008
/09
Observed cases
Predicted cases (withherd immunity)
Predicted cases (noherd immunity)
Trotter et al, Am J Epi 2005, 162: 89-100
Confidentiel MVP est un partenariat entre l’OMS et PATH
Introduction of Men A conjugate vaccine in Africa
All 1-29 year olds in Burkina Faso to receive
one dose of Men A conjugate vaccine 2008
Campaigns in Mali and Niger 2009
Begin campaigns in Nigeria, Sudan and
Ethiopia 2010
Add more belt countries 2011-2020
Confidentiel MVP est un partenariat entre l’OMS et PATH
Potential Public Health Benefit From a Men A Conjugate Vaccine in Nigeria
Epidemic meningitis in Nigeria
20 000
40 000
60 000
80 000
100 000
120 000
1 4 7 10 13 16 19 22 25 28 31 34 37
Years
Cas
es Nigeria
Over 130,000 potentially preventable cases of meningitis in years 77,78,86,87 and 96
65 70 75 80 85 90 95 00
Confidentiel MVP est un partenariat entre l’OMS et PATH
Potential Public Health Benefit from the Prevention of Men A Epidemics in Mali
Mali
2 000
4 000
6 000
8 000
10 000
12 000
14 000
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39
Mali
Over 32,000 potentially preventable cases during epidemic years
69,70,81,82,96,97 and 98
65 70 75 80 85 90 95 00
Epidemic meningitis in Mali 1965-2003Cases
Years
Confidentiel MVP est un partenariat entre l’OMS et PATH
Meningitis in Niger
0
100
200
300
400
500
600
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Years
Inc
ide
nc
e p
er
10
0,0
00
Niger*
Residual endemic disease
Meningitis in Niger 1981-2003
0
100
200
300
400
500
600
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Years
Inc
ide
nc
e p
er
10
0,0
00
NigerEndemicdisease
Epidemic disease
81 85 90 95 00
Potential Impact of a Men A Conjugate Vaccine
81 85 90 95 00
Confidentiel MVP est un partenariat entre l’OMS et PATH
What will not happen
• Acute meningitis cases will not be eliminated
(particularly important in the group less than two years of age where most cases of acute bacterial meningitis are due to Hemophilus and pneumococci)
Confidentiel MVP est un partenariat entre l’OMS et PATH
The Meningitis Vaccine Project