MALARIA ELIMINATION IN ZANZIBAR - Soper Strategies

EXECUTIVE SUMMARY
Over the past several years, the islands of Zanzibar have made
dramatic progress in reducing the burden of malaria, driving the
parasite prevalence down from historic levels of more than 70% to
less than 1.5% currently. As a result of this success, the Zanzibar
Malaria Control Program (ZMCP) finds itself at a crossroads: it
can seek to maintain and marginally improve its current control
operations in order to indefinitely keep malaria suppressed but
still present (so-called “sustained control”), or it can attempt to
eliminate malaria from the islands altogether. This decision has
significant programmatic, financial, and technical implications.
As such, the Ministry of Health and Social Welfare (MOHSW)
is determined to engage in careful analysis and deliberation
before determining the way forward. To reach an appropriately
informed decision, the MOHSW has sought answers to a range
of critical questions, including: Can elimination be feasibly
achieved in Zanzibar? If elimination is achieved, can malaria-free
status be maintained in perpetuity? What will the ongoing costs
of an elimination program be and how will these compare to
sustaining current control measures?
Due to the lack of focus on malaria elimination over the past
three decades and the innate complexity of the issue, answers
to these questions are not readily available from current sources.
As a result, the MOHSW asked the ZMCP to conduct a
comprehensive assessment of the feasibility of elimination on
Zanzibar, drawing on international best practice and in-depth
analysis of conditions on the islands. The ZMCP accordingly
brought together a group of local and international experts
from a range of institutions to assist it in producing a highquality
assessment and commenced the exercise in July 2008.
As current international guidance on how to assess elimination
feasibility is unspecific, the working group drew on frameworks
from the Global Malaria Eradication Program in the 1950’s-
60’s to develop an appropriate contemporary methodology for
the assessment. This methodology examines the question of
elimination feasibility along three key dimensions:
�� Technical Feasibility: Can complete interruption of malaria
transmission on Zanzibar be achieved and sustained using the
currently available control tools?
�� Operational Feasibility: What measures must be in place
to achieve the level of interventions required to reach and
sustain elimination?
�� Financial Feasibility: What is the cost of a malaria elimination
program compared to a sustained control program? How can
Zanzibar sustainably finance its malaria interventions?
The working group pursued these questions sequentially through
a range of methods, including literature reviews, consultation
with local officials and key informants, and mathematical
modeling. The technical feasibility analysis, which forms the
core of the overall assessment, relies on a series of new or adapted
mathematical models that estimate critical epidemiological
determinants and predict the impact of various interventions
on malaria transmission. The operational implications of the
interventions recommended by the technical feasibility exercise
were then estimated by determining the gaps in the relevant
systems and the capacity that would be required to enable the
intervention coverage needed to achieve elimination. Lastly, both
the interventions and supporting systems and capacity needed
to achieve and sustain elimination were costed using standard
techniques and compared to updated cost estimates of sustained
control.
It is important to use caution when interpreting the results of
this assessment. There are major gaps in global understanding
of malaria elimination that required the working group to limit
the scope of analysis and/or make assumptions in some areas.
Mathematical modeling is always incapable of fully replicating
real world conditions and was further limited in this exercise by
the lack of data for some analyses. And the estimation of costs
and impact over a period as long as 25 years into the future is
inherently limited by the inability to predict change in conditions
that could fundamentally influence key outputs (e.g., overall
wealth, health system strength, or climate).
Given these limitations and the scope and objectives of the
work, it is recommended that the information provided in this
report be used primarily for strategic planning purposes and not
detailed operational activities (e.g., commodity quantification).
Nevertheless, the working group is confident that this assessment
provides the MOHSW with a robust analysis of this issue and
therefore a strong foundation from which to make its strategic
decisions.
RECOMMENDATIONS
Based on its analysis, the feasibility working group reached a
series of conclusions on the core questions that prompted the
assessment and recommended steps that the MOHSW should
take if it decides to pursue malaria elimination. They include:
Technical Feasibility
�� Mathematical models indicate that local malaria transmission
on Zanzibar can be reduced to zero through universal coverage
with vector control measures. This interruption of transmission
can be achieved by maintaining high coverage of indoor
residual spraying or long-lasting insecticide-treated bed nets.
! Given Zanzibar’s high innate transmission potential and
outbreak risk, current IRS activities should not be scaled
back until surveys indicate that effective coverage (usage)
of LLINs is 75% or above.
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