lessons from measles outbreaks in the african region
DESCRIPTION
Lessons from Measles outbreaks in the African Region. Annual Measles Partnership meeting Feb 2007 Washington DC. Outline. Quality of surveillance Measles outbreaks in 2006 Lessons learnt. Quality of surveillance Measles outbreaks in 2006 Lessons learnt. - PowerPoint PPT PresentationTRANSCRIPT
Lessons from Measles outbreaks in the African
Region
Annual Measles Partnership meeting
Feb 2007Washington DC
2Bureau Régional de l’OMS pour l’Afrique / WHO Regional Office for Africa
3Bureau Régional de l’OMS pour l’Afrique / WHO Regional Office for Africa
Outline
• Quality of surveillance
• Measles outbreaks in 2006
• Lessons learnt
4Bureau Régional de l’OMS pour l’Afrique / WHO Regional Office for Africa
• Quality of surveillance
• Measles outbreaks in 2006
• Lessons learnt
5Bureau Régional de l’OMS pour l’Afrique / WHO Regional Office for Africa
The AFR measles surveillance and lab network (Feb 2007)
• A total population of 668.5 million under case based surveillance for measles
6Bureau Régional de l’OMS pour l’Afrique / WHO Regional Office for Africa
Measles surveillance performance indicators in AFR. 2002 - 2006
0%10%20%30%40%50%
60%70%80%90%
100%
Districts Reporting Blood SpecimensCollected
Lab ConfirmedMeasles
2002
2003
2004
2005
2006
7Bureau Régional de l’OMS pour l’Afrique / WHO Regional Office for Africa
Measles surveillance performance & results. AFR. 2006
Indicator/ parameter Result
# suspected cases reported 21580
% investigated with blood specimens 93%
% districts reporting at least 1 suspected case
54%
% lab confirmed cases 30%
# total confirmed measles cases 7707
Incidence rate of confirmed measles 1.2 per 100,000 population
8Bureau Régional de l’OMS pour l’Afrique / WHO Regional Office for Africa
• 22 countries > 2 suspected cases investigated per 100,000 population
• 15 countries >80% districts reporting
• 24 countries > 60% districts reporting
• 25 countries < 1: 100,000 incidence of confirmed measles
Measles surveillance performance & results. AFR. 2006 (2)
9Bureau Régional de l’OMS pour l’Afrique / WHO Regional Office for Africa
Incidence of confirmed measles per 100,000 population by country. 2006
10Bureau Régional de l’OMS pour l’Afrique / WHO Regional Office for Africa
• Quality of surveillance
• Measles outbreaks in 2006
• Lessons learnt
11Bureau Régional de l’OMS pour l’Afrique / WHO Regional Office for Africa
– In 2004, 80 (5%) of a total of 1590 districts covered by the case based surveillance system reported outbreaks
– In 2005, outbreaks in 47 (3%) districts out of 1850
– In 2006, 178 (6%) of 2923 districts in 12 countries have experienced outbreaks.
NB: Tanzania database incomplete
Measles outbreaks in the African Region (2004 - 2006)
12Bureau Régional de l’OMS pour l’Afrique / WHO Regional Office for Africa
Probable causes of measles outbreaks in the African Region in 2006
• Accumulation of unvaccinated cohorts (~ over
3 -4 years) due to a combination of factors
– sub-national gaps in routine EPI coverage:
• Angola, Benin, DR Congo, Ethiopia, Mali, Tanzania,
Uganda
– delays in conducting follow up SIAs:
• Kenya, Zambia, Ghana
• cross border spread of outbreaks:• DR Congo, Rwanda
13Bureau Régional de l’OMS pour l’Afrique / WHO Regional Office for Africa
Outbreak countries. AFR. 2006
Country Average MCV
coverage
(‘03 –‘05)
Interval b/n last SIAs and
onset of outbreak (months)
# (%) districts involved
Size of largest cluster (cases/
district)
Confirmed measles
Incidence rate
Angola 57 32 13 (8%) 118 4.0
Benin 84 4 4 (5%) 17 2.3
Ghana 82 37 4 (4%) 10 0.4
Kenya 71 40 71 (90%) 162 5.0
Mali 76 14 3 (5%) 79 1.0
Rwanda 88 32 2 (5%) 468 5.5
Tanzania 94 12
Uganda 87 29 29 (52%) 126 3.2
Zambia 79 35 8 (11%) 44 1.5
14Bureau Régional de l’OMS pour l’Afrique / WHO Regional Office for Africa
Outbreak countries. AFR. 2006
Country Average MCV
coverage
(‘03 –‘05)
Interval b/n last SIAs and
onset of outbreak (months)
# (%) districts involved
Size of largest cluster (cases/
district)
Confirmed measles
Incidence rate
Angola 57 32 13 (8%) 118 4.0
15Bureau Régional de l’OMS pour l’Afrique / WHO Regional Office for Africa
Outbreak countries. AFR. 2006
Country Average MCV
coverage
(‘03 –‘05)
Interval b/n last SIAs and
onset of outbreak (months)
# (%) districts involved
Size of largest cluster (cases/
district)
Confirmed measles
Incidence rate
Ghana 82 37 4 (4%) 10 0.4
16Bureau Régional de l’OMS pour l’Afrique / WHO Regional Office for Africa
Outbreak countries. AFR. 2006
Country Average MCV
coverage
(‘03 –‘05)
Interval b/n last SIAs and
onset of outbreak (months)
# (%) districts involved
Size of largest cluster (cases/
district)
Confirmed measles
Incidence rate
Zambia 79 35 8 (11%) 44 1.5
17Bureau Régional de l’OMS pour l’Afrique / WHO Regional Office for Africa
Outbreak countries. AFR. 2006
Country Average MCV
coverage
(‘03 –‘05)
Interval b/n last SIAs and
onset of outbreak (months)
# (%) districts involved
Size of largest cluster (cases/
district)
Confirmed measles
Incidence rate
Kenya 71 40 71 (90%) 162 5.0
18Bureau Régional de l’OMS pour l’Afrique / WHO Regional Office for Africa
Trends in confirmed measles cases. Kenya. 2003 - 2006
0
50
100
150
200
250
300
350
400
2003 2004 2005 2006
num
ber
of c
onfir
med
mea
sles
cas
es
Trends of confirmed measles cases. Kenya. 2003 –2006.
F-up SIAs done July ‘06
Catch-up SIAs:
June ‘02
F-up SIAs postponed
19Bureau Régional de l’OMS pour l’Afrique / WHO Regional Office for Africa
Measles cases in Kenya. 2006
20Bureau Régional de l’OMS pour l’Afrique / WHO Regional Office for Africa
0
100
200
300
400
500
600
< 9 months 9 - 11months
1 - 4 years 5 - 14 years 15+ years
co
nfi
rme
d m
ea
sle
s c
as
es
unknown
not vaccinated
vaccinated
Confirmed measles cases by age and vaccination status. Kenya. 2006
21Bureau Régional de l’OMS pour l’Afrique / WHO Regional Office for Africa
Outbreak countries. AFR. 2006
Country Average MCV
coverage
(‘03 –‘05)
Interval b/n last SIAs and
onset of outbreak (months)
# (%) districts involved
Size of largest cluster (cases/
district)
Confirmed measles
Incidence rate
Uganda 87 29 29 (52%) 126 3.2
22Bureau Régional de l’OMS pour l’Afrique / WHO Regional Office for Africa
Trends in confirmed measles cases. Uganda. 2002 - 2006
0
20
40
60
80
100
120
140
160
180
2002 2003 2004 2005 2006
nu
mb
er
of
con
firm
ed
meas
les c
ase
s
Trends of confirmed measles cases. Uganda. 2002 – 2006.
Catch-up SIAs: Oct
2003
F-up SIAs: Nov 2006
23Bureau Régional de l’OMS pour l’Afrique / WHO Regional Office for Africa
Measles cases in Uganda. 2006
24Bureau Régional de l’OMS pour l’Afrique / WHO Regional Office for Africa
Confirmed measles cases by age and vaccination status. Uganda. 2006
0
50
100
150
200
250
300
350
400
< 9 months 9 - 11months
1 - 4 years 5 - 14 years 15+ years
co
nfi
rme
d m
ea
sle
s c
as
es
unknown
not vaccinated
vaccinated
25Bureau Régional de l’OMS pour l’Afrique / WHO Regional Office for Africa
Probable causes of measles outbreaks in the African Region in 2006 (2)
– Program gaps leading to a cohort of older
children (ages 6 – 7.5 years) unprotected in
some districts
• Tanzania (124 districts)
– 1999 / 2000 SIAs: all 9 – 59 months (in 91 districts)
– 2001 SIAs: 9 months – 14 years (in 31 districts)
– 2002 SIAs: 7 – 14 years (in 89 districts)
– 2005 SIAs: 9 - 59 months (nation-wide follow up)
26Bureau Régional de l’OMS pour l’Afrique / WHO Regional Office for Africa
Age distribution of measles cases. Dar es Salaam, Tanzania
July – mid Oct. 2006
27Bureau Régional de l’OMS pour l’Afrique / WHO Regional Office for Africa
Disturbing gaps in the quality of data
Country % cases with age missing
% cases with vaccination status missing/ unknown
DRC 30% 44%
Ethiopia - 55%
Kenya 4% 55%
Tanzania - 78%
Uganda - 82%
Ghana 14% 41%
28Bureau Régional de l’OMS pour l’Afrique / WHO Regional Office for Africa
• Quality of surveillance
• Measles outbreaks in 2006
• Lessons learnt
29Bureau Régional de l’OMS pour l’Afrique / WHO Regional Office for Africa
Lessons learnt
• Postponing measles follow-up SIAs beyond 36
months is risky even in “high” coverage countries
– Other platforms available for integration
– Disparities in the district level coverage
• Surveillance and outbreak investigation should
provide better quality epidemiological information
– Training and technical support for outbreak investigation
30Bureau Régional de l’OMS pour l’Afrique / WHO Regional Office for Africa
Lessons learnt (2)
• Political visibility of outbreaks;
– an opportunity to advocate for routine EPI and good quality
follow up SIAs
• Identify districts at high risk for outbreaks for extra
support to intensify immunization activities
31Bureau Régional de l’OMS pour l’Afrique / WHO Regional Office for Africa
Thank you