Strategy to eradicate polio in the Democratic Republic of the Congo
Context
Conflict in the Democratic Republic of the Congo (DRC) has contributed to a weak health system, low routine immunization coverage and insufficient capacity to fully implement international polio outbreak response guidelines.
These factors have led to circulation of imported wild poliovirus that is suspected to have persisted for more than 12 months, and the country is classified as having re-established transmission. Furthermore, in 2009, re-established polioviruses in DRC re-infected other, previously polio-free countries and areas.
Wild polioviruses suspected to have been re-established in DRC have not been detected since August 2008. Consequently, the priority is to enhance surveillance sensitivity to determine whether virus is continuing to circulate. At the same time, large scale supplementary immunization activities must be continued to protect against the possible re-emergence of the most recent virus as well as new importations.
Strategic approach in Africa
Compared with Asia, poliovirus transmission persists over a broad area in Africa. In addition, polio outbreaks due to importations generally result in more polio cases over longer periods of time than in Asia. Both are due to weak health systems, resulting in low immunization coverage.
These challenges are off-set by consistently high per-dose efficacy of oral polio vaccine in Africa, and a lower population immunity threshold (80–85%) needed to stop poliovirus transmission.
Consequently, the immunity thresholds needed to stop polio transmission in Africa can be achieved with relatively fewer vaccination campaigns over wide areas and maintaining high coverage.
Strategic approach in the Democratic Republic of the Congo
Interrupting the remaining poliovirus transmission in Angola requires the following activities.
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Improving the quality of large-scale supplementary immunization activities to sustain population immunity and protect against the possible re-emergence of the most recent virus as well as new importations.
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Enhancing sensitivity of acute flaccid paralysis surveillance to determine whether the poliovirus is continuing to circulate.
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Enhancing resources – particularly international technical assistance and communications – to levels which are comparable to the investment in endemic areas.
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Establishing specific mechanisms to monitor the engagement of provincial and district leaders, with oversight by the Office of the President.
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Revising outbreak-response microplans for each area, with refresher training of all key staff.
Eradication targets
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End–2010: all re-established wild poliovirus transmission interrupted and <10% missed children in each supplementary immunization activity in Orientale, north and south Kivu (and all provincial capitals); acute flaccid paralysis rate >2 with 80% adequate specimens in all provinces.
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End–2011: supplementary immunization activity and acute flaccid paralysis surveillance performance of 2010 sustained.
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End–2012: supplementary immunization activity and acute flaccid paralysis surveillance performance of 2010 sustained.