Abstract
SummaryBackgroundCholera remains a persistent health problem in sub-Saharan Africa and worldwide. Cholera can be controlled through appropriate water and sanitation, or by oral cholera vaccination, which provides transient (∼3 years) protection, although vaccine supplies remain scarce. We aimed to map cholera burden in sub-Saharan Africa and assess how geographical targeting could lead to more efficient interventions.MethodsWe combined information on cholera incidence in sub-Saharan Africa (excluding Djibouti and Eritrea) from 2010 to 2016 from datasets from WHO, Médecins Sans Frontières, ProMED, ReliefWeb, ministries of health, and the scientific literature. We divided the study region into 20 km × 20 km grid cells and modelled annual cholera incidence in each grid cell assuming a Poisson process adjusted for covariates and spatially correlated random effects. We combined these findings with data on population distribution to estimate the number of people living in areas of high cholera incidence (>1 case per 1000 people per year). We further estimated the reduction in cholera incidence that could be achieved by targeting cholera prevention and control interventions at areas of high cholera incidence.FindingsWe included 279 datasets covering 2283 locations in our analyses. In sub-Saharan Africa (excluding Djibouti and Eritrea), a mean of 141 918 cholera cases (95% credible interval [CrI] 141 538–146 505) were reported per year. 4·0% (95% CrI 1·7–16·8) of districts, home to 87·2 million people (95% CrI 60·3 million to 118·9 million), have high cholera incidence. By focusing on the highest incidence districts first, effective targeted interventions could eliminate 50% of the region's cholera by covering 35·3 million people (95% CrI 26·3 million to 62·0 million), which is less than 4% of the total population.InterpretationAlthough cholera occurs throughout sub-Saharan Africa, its highest incidence is concentrated in a small proportion of the continent. Prioritising high-risk areas could substantially increase the efficiency of cholera control programmes.FundingThe Bill & Melinda Gates Foundation.
Highlights
Cholera is one of the oldest known infectious diseases
Spurred by large outbreaks in Yemen, Tanzania, Haiti, and elsewhere in the past decade and the availability of new methods to control cholera outbreaks, the WHOled Global Task Force on Cholera Control has laid out a roadmap for ending cholera as a public health threat by 2030.5 Access to safe water, appropriate sanitation, and hygiene (WaSH) remains the foundation of sustained cholera control, but a new generation of easy-to-use oral cholera vaccines (OCVs) have an important role
We found that 21·7 million people (95% credible intervals (CrIs) 19·8 million to 23·7 million) in sub-Saharan Africa live in areas of high-cholera incidence (20 km × 20 km grid cells in which more than one in 1000 people are reported as infected with cholera each year), and 87·2 million (95% CrI 60·3 million to 118·9 million) live in districts with high incidence
Summary
Cholera is one of the oldest known infectious diseases. Seven times in recorded history, cholera has emerged from its presumed natural home near the Bay of Bengal and spread globally. Spurred by large outbreaks in Yemen, Tanzania, Haiti, and elsewhere in the past decade and the availability of new methods to control cholera outbreaks, the WHOled Global Task Force on Cholera Control has laid out a roadmap for ending cholera as a public health threat by 2030.5 Access to safe water, appropriate sanitation, and hygiene (WaSH) remains the foundation of sustained cholera control, but a new generation of easy-to-use oral cholera vaccines (OCVs) have an important role These vaccines are socially acceptable, safe, and effective for prevention of cholera for at least 3 years after administration.[6] OCVs can curb transmission in the short term, preventing death and disease while crucial improvements to infrastructure are made. Supplies are increasing every year, the number of OCV doses available (~17 million produced in 2017)[7] remains too low for large, generalised campaigns.Even if adequate supplies become available, broad use of a vaccine with only transient protection is unlikely to be cost-effective in populations in which few are at high risk, www.thelancet.com Vol 391 May 12, 2018
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