Polio eradication in the African Region: Progress and way forward
Alex Gasasira, Joseph Okeibunor, Mbaye Salla, Nicksy Gumede, Deo Nshimirimana
Corresponding author: Joseph Okeibunor; e-mail: firstname.lastname@example.org
WHO Regional Office for Africa, Brazzaville Congo
© WHO/Julie Pudlowski
Following the declaration of global polio eradication as a programmatic emergency for public health in 2012,1,2 targets and milestones were set (see Figure 1); and innovative approaches were taken to address the polio situation in the African Region. The innovations include, but are not limited to quarterly meetings with the four priority countries (Angola, Chad, Democratic Republic of the Congo, Nigeria) and WHO representative’ monthly reports on polio in the polio affected countries. In Nigeria there is a presidential task force with governors involved, and in Chad the president chairs monthly Polio Eradication Initiative (PEI) meetings. Traditional and cultural leaders meet regularly in all affected countries. Further efforts made to enhance the implementation of polio activities include the surge in human resources boosted with staff from CDC, the Bill & Melinda Gates Foundation and WHO. Nigeria has 2 207 staff, Chad 43 and the Democratic Republic of the Congo 43. There is also a deployment of India surveillance medical officers to support emergency plans in Nigeria.
In terms of core programming, supplementary immunization activities (SIAs) and surveillance received a major boost during the emergency period. To this effect, there was a restructuring of polio teams, development of polio dashboards (see Figure 2), and the use of GIS/GPS to support micro-planning and support monitoring of vaccination teams. Furthermore, independent monitoring has also been improved; there is routine immunization strengthening between rounds of polio campaigns, lots quality assurance sampling (LQAS) is being used to monitor the quality of campaigns, and environmental surveillance has been initiated in Nigeria, Kenya and, recently, in Angola.
Strategies have also been put in place to reach nomads in Chad and Nigeria. One such strategy is the involvement of nomadic populations in planning and execution of vaccinations. Emphasis is placed on transport and intra-nomadic population capacity for oral polio vaccine (OPV) delivery. There is also cross-border collaboration between the African and Eastern Mediterranean WHO regional offices and between countries (for example, Ethiopia and South Sudan). Communication and social studies are being conducted to better understand the under-immunization in Angola and Nigeria. Special emphasis is placed on the interpretation of being a vaccinator and reasons for poor interactions between vaccinators and supposed recipients. The polio dashboard was developed and used to monitor implementation of polio eradication activities.
The efforts put into achieving these results, namely SIAs, planning, monitoring and surveillance have been evaluated and documented in some studies.3,4 The Region seems set to stop the transmission of polio by the end of 2015 as targeted in the milestones. This article gives a brief report on the successes, challenges and the way forward.
Polio transmission in the African Region
Twelve countries, in the African Region, had active wild poliovirus (WPV) transmission with a total of 350 cases in 2011. In 2014, as of week 33, the number of African countries with the wild poliovirus had decreased significantly showing only 16 WPV cases from four countries (Cameroon, Ethiopia, Equatorial Guinea, and Nigeria). Previous re-established transmission countries have been able to interrupt WPV transmission. Angola, for instance, has remained poliovirus free for more than three years now; Democratic Republic of the Congo for almost three years and Chad for more than two years. The last WPV case in Chad was recorded on 14 June 2012. Oral polio vaccine coverage in polio reservoirs is constantly reducing, indicating greater acceptance of the vaccine and reducing the number of cases.
The three remaining foci of transmission in the African Region are Nigeria, the Central Africa subregion and the Horn of Africa. All three foci continue to show persistent transmission of WPV, albeit with much lower intensity, as the timeline for cessation of transmission approaches. All the same, while Nigeria still witnesses some cases of circulating vaccine-derived polioviruses (cVDPV2) the other subregions have not reported any cases of cVDPV in 2014. In total, 18 cVDPV2 cases were reported in the region as of week 33 of 2014 and all from Nigeria.
Actions taken to get us here
Steps were taken to rapidly improve population immunity with a focus on infected and high-risk areas. Some of these steps include intensified SIAs scheduled in all infected countries with the implementation of expanded age group campaigns in outbreak countries. Special initiatives were employed in areas where security was compromised, including targeted use of IPV.
Furthermore, efforts were put into rapidly closing gaps in poliovirus detection through the enhancement of acute flaccid paralysis (AFP) surveillance field activities, expansion of environmental surveillance and increased support to polio laboratories, especially in outbreak countries. Certification and containment systems were also reinvigorated.
The Region has also witnessed tremendous improvements in a number of public health indicators that may have contributed to this progress towards eradication of polio in line with the global targets. For instance there has been a gradual but sustained improvement in routine immunization. The coverage of infants by age 12 months with three doses of polio vaccine (Pol3) through routine immunization rose from less than 10% in 1980 to 77% in 2013.5
This was complemented with successful SIAs and sustained effective polio surveillance. In 2013, 265 SIAs, using OPV were conducted in 42 countries, 52% in the African Region.1 These included national immunization days (NIDs), subnational immunization days (SNIDs), child health days and large-scale mop up rounds. With an effective AFP surveillance system in place, polio cases caused by WPV and cVDPV were detected and stool specimens tested in WHO accredited laboratories.6
All the same, it is important to note that “the number of WPV cases in outbreaks after WPV importation into previously polio-free countries increased from six cases in two countries (Chad and Niger) in 2012 to 27 cases in three countries (Cameroon, Ethiopia and Kenya) in 2013. Importation of WPV type1 (WPV1) from Nigeria into the Horn of Africa resulted in 217 cases in 2013 (9 in Ethiopia, 14 in Kenya and 194 Somalia); one WPV1 case was reported by Ethiopia in 2014. Four WPV1 cases were reported in Cameroon in 2013 and five in 2014, five cases have so far been reported in Equatorial Guinea and five WPV1 cases reported in Nigeria as at week 33 of 2014. On genomic sequence analysis, the isolates were of Nigerian origin most closely linked with WPV cases reported from Chad in 2012.”1
The way forward
Despite the occurrence of recent outbreaks, considerable progress has been made toward polio eradication in the African Region. The last WPV3 case in the Region and globally was recorded in Nigeria in 2012 signifying a successful interruption of WPV3 transmission in the Region. The transmission of indigenous WPV in the Region has been narrowed to restricted geographical areas. The significant decrease in the number of WPV cases and number of affected geographical entities in the Region has been attributed to the significant improvement in a number of programmatic indicators including quality of SIAs, routine immunization and AFP surveillance, albeit gaps at subnational level in surveillance quality remain an issue of concern. The plan for carrying the initiative forward to the finishing line includes the intensification of efforts at interrupting transmission, continued enhancement of AFP surveillance, as well as immunization strengthening.
With respect to interruption of transmission, advocacy to critical stakeholders and decision-makers will be undertaken to increase and sustain national commitment to stopping poliovirus transmission. High quality, synchronized SIAs will continue to be implemented in Nigeria, and Central and West Africa, where threats of transmission remain a concern.
The enhancement of poliovirus detection will take the form of strengthening field surveillance activities in all geographical entities with suboptimal AFP surveillance performance. Further still, there will be a deliberate expansion of environmental surveillance activities as well as continued and deliberate support to strengthen routine immunization systems. p
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