Evaluating Pneumococcal Conjugate Vaccine in Kenya

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Evaluating Pneumococcal Conjugate Vaccine in Kenya

• Dr Anthony Scott
• Wellcome Trust/KEMRI
• Centre for Geographic Medicine Research - Coast
• Kilifi, Kenya

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Timetable for PCV introduction

• Supply of Prevenar gt dev. world need
• Other vaccines not available for several years
• PneumoADIP recommend GAVI invest now
• GAVI decision due in November
• Vaccine may be available in 2008

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What do countries need to respond?

• Regional evidence of efficacy
• Schedule / effect on existing vaccines
• Cost of vaccine under GAVI support
• Cost-effectiveness of vaccine
• Mechanism for monitoring vaccine impact
• Forward purchase and introduction plan
• Roll out vaccine

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Gambia Trial Results
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South Africa Trial Results
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What do countries need to respond?

• Regional evidence of efficacy
• Schedule / effect on existing vaccines
• Cost schedule under GAVI support
• Cost-effectiveness of vaccine
• Mechanism for monitoring vaccine impact
• Forward purchase and introduction plan
• Roll out vaccine

?
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What do countries need to respond?

• Regional evidence of efficacy
• Schedule / effect on existing vaccines
• Cost schedule under GAVI support
• Cost-effectiveness of vaccine
• Mechanism for monitoring vaccine impact
• Forward purchase and introduction plan
• Roll out vaccine

? ?
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Cost-effectiveness of PCV
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Disease prevented by vaccine
Is disease caused by serotypes included in the
vaccine?

• Diseases in those vaccinated
• Invasive pneumococcal disease
• Radiologically confirmed pneumonia
• Meningitis
• Death

Herd protection in those not vaccinated
Serotype replacement disease
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Serotypes in the region
Data from Kilifi District Hospital, 1994-2004
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Serotypes in the region
Data from Kilifi District Hospital, 1994-2004
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How does herd protection work?
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How does herd protection work?
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How does herd protection work?
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How does herd protection work?
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Herd protection from PCV7 in USA
Anon.MMWR 200554893-7
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Projected USA effectiveness 2003
Anon.MMWR 200554893-7
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Serotype replacement disease?
PCV7
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Serotype replacement disease
Projections for USA 2003 based on ABCs
surveillance
Anon.MMWR 200554893-7
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Total disease prevented in USA
no. of cases of IPD (all ages)
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What do countries need to respond?

• Regional evidence of efficacy
• Schedule / effect on existing vaccines
• Cost schedule under GAVI support
• Cost-effectiveness of vaccine
• Mechanism for monitoring vaccine impact
• Forward purchase and introduction plan
• Roll out vaccine

? ? ?
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Can netSPEAR provide this data?

• can monitor IPD frequency
• can monitor serotype changes
• BUT
• need stable/comprehensive surveillance
• need to report the age of the patient
• need to match isolates to reports accurately
• netspear limited to IPD endpoint in children only

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PCV7 effectiveness study in Kenya

• Partners and funders
• Kenya Ministry of Health
• GAVI
• Pneumo ADIP
• Kenya Medical Research Institute
• Wellcome Trust

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PCV7 effectiveness study in Kenya
Location two districts in Kenya

• District 1
• incidence rates
• herd protection
• serotype replacement

District 2 different epi setting direct
protection serotype replacement
Design before-after comparison disease freq
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Effectiveness of Hib vaccine
Invasive disease endpoint only
Children lt5yrs (vaccine target group only)
Slow effect of vaccine over 3-4 years
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Spn carriage prevalence in Kilifi
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Vaccine coverage in Kilifi
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Unvaccinated children under 18m
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Unvaccinated children under 5 yrs
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Unvaccinated children under 5 yrs
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Unvaccinated population
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Measuring what? - Endpoints

• Invasive Pn disease - vaccine type
• Invasive Pn disease - non-vaccine type
• Radiologically confirmed pneumonia (children)
• All admissions to hospital (children)

Effectiveness of 1, 2, 3 doses of
vaccine Effectiveness of vaccine in HIV Effect of
vaccine on carriage of pneumococci Serological
evidence of population immunity over time
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Timescale
PCV7 infants
IPD surv. in adults
IPD surveillance in children
01
02
03
04
05
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07
08
09
10
11
year
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Cost-effectiveness in 2010/2011
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Checklist at 2010

• Regional evidence of efficacy
• Schedule / effect on existing vaccines
• Cost schedule under GAVI support
• Cost-effectiveness of vaccine
• Mechanism for monitoring vaccine impact
• Forward purchase and introduction plan
• Roll out vaccine

• ?
• ?
• ?
• ?
• ?
• ?

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