Progress against the polio eradication and endgame strategic plan 2013-2018: Semi-annual status report, July to December 2015
By the end of 2015, strong progress continued towards each of the Endgame Plan’s four objectives. The world has never been closer to eradicating polio, with fewer cases in fewer areas of fewer countries than at any time in the past. The virus is now more geographically constrained than at any point in history. As the GPEI enters 2016, it is more important than ever to redouble efforts to eradicate poliovirus in every corner of the globe.
Recognizing the progress made towards interrupting transmission, at its meeting in October 2015 the Strategic Advisory Group of Experts on immunization (SAGE) congratulated the GPEI and Member States on their contributions to the eradication effort.
The SAGE reaffirmed the date of April 2016 for the switch from trivalent oral polio vaccine (tOPV) to bivalent OPV (bOPV).
A year without polio in Nigeria
In Nigeria, no new cases of wild poliovirus type 1 (WPV1) have occurred since a case with onset of paralysis on 24 July 2014 was reported. WHO declared Nigeria free from endemic polio on 24 September 2015. Three years with no polio cases and certificationstandard surveillance are required before the Africa Regional Certification Commission determines whether the WHO Africa Region can be certified polio-free.
Regional insecurity continues to result in subnational surveillance gaps in Nigeria.
Furthermore, immunization gaps persist, especially in the northern areas. These gaps must be filled for Nigeria to mitigate the risk of reinfection with the disease.
A circulating vaccine-derived poliovirus (cVDPV) case with onset of paralysis on 16 May 2015 did not result in further cases in the second half of the year, raising hopes that the aggressive response was effective against the outbreak of this strain. However, its emergence in the first place underscores again the very real risk subnational immunity gaps continue to pose to populations, and the fragility of the progress achieved.
Progress in Afghanistan and Pakistan
Progress reported in the first half of 2015 continued into the second half of the year – typically the high season for polio transmission.
Afghanistan and Pakistan continue to be treated as a single epidemiological block, with greater coordination between the two to interrupt transmission.
Pakistan is moving back on track. A total of 25 cases had onset of paralysis in the second half of 2015 – a vast improvement on the 206 in the second half of 2014. A national emergency action plan is being overseen by the office of the prime minister, focusing on identifying and reaching chronically missed children with the polio vaccine. Despite this improvement, vaccination gaps persist in Karachi, in the Peshawar-Khyber corridor and in parts of the Quetta block. Pakistan introduced inactivated polio vaccine (IPV) into its routine immunization schedule in July.
In the second half of 2015, 14 cases of WPV were reported in Afghanistan. Ten of these were reported in the neighbouring provinces of Nangarhar and Kunar, which border infected regions of Pakistan. This represents a decrease from the 20 cases reported in Afghanistan during the same period in 2014. Endemic circulation continues to be a concern. Security issues still hinder reaching children in some areas of the country, as do operational challenges in fully implementing supplementary immunization activities. No cVDPV cases have been reported since March 2013. Afghanistan introduced IPV into its routine immunization schedule in September 2015.
Continued progress in central Africa, the Horn of Africa and the Middle East
Outbreaks in central Africa, the Horn of Africa and the Middle East appear to have stopped.
Due to the risk of residual immunity and subnational surveillance gaps in some parts of all three areas, comprehensive risk-mitigation activities are continuing there.
Ongoing responses in other areas
In Madagascar, an outbreak of circulating vaccine-derived poliovirus type 1 (cVDPV1) continued into the second half of 2015, with a further two cases reported in July and August.
Both cases were linked to cVDPV1 that was detected in the second half of 2014. As time progresses, hopes are raised that this outbreak has also been brought to a close. Further cVDPV1 outbreaks occurred in Ukraine, with a second case in 2015 reported in July, and in Lao People’s Democratic Republic, with eight cases between September and December 2015.
Outbreaks of circulating vaccine-derived poliovirus type 2 (cVDPV2) occurred in Guinea, with four cases reported between July and October, and in Myanmar, with one case in October and one retrospectively assigned with onset in April. While this is far fewer than reported in 2014, emerging cVDPV outbreaks are symptomatic of low immunization coverage in the affected areas.
Recognizing the increasing importance of cVDPV outbreaks in the Endgame Plan, the risks that ongoing subnational surveillance gaps pose in allowing such strains to arise, and the urgent need for the phased removal of OPVs, the International Health Regulations Emergency Committee extended its Temporary Recommendations under the “public health emergency of international concern” to countries affected by such strains. Previously, the Temporary Recommendations had been limited to countries affected by WPV.
Preparation for the withdrawal of oral polio vaccines and the strengthening of routine immunization systems
The SAGE met in October 2015 and concluded that preparations for the global switch from tOPV to bOPV are on track. Having reviewed transmission data, the SAGE established that the continued use of tOPV in immunization systems constitutes a greater public health risk than do the risks of proceeding with its withdrawal. According to its recommendation, the largest-ever globally coordinated vaccine switch will go ahead in April 2016. All tOPV will be removed from use and replaced by bOPV.
Containment and certification
In September 2015, the Global Commission for Certification of the Eradication of Poliomyelitis (GCC) declared that WPV2 has been eradicated.
No cases of WPV2 have been reported since 1999. Containment activities are being further intensified in the run-up to the tOPV to bOPV switch in April 2016, to guard against any accidental release of poliovirus that could once again cause paralysis and death.
In the second half of 2015, work continued to ensure the investments made in polio eradication serve as a foundation for future global health objectives. In 2015, the GPEI reached more children than ever before, including children in remote and often insecure areas. The lessons learned and infrastructure built can continue to reap rewards after eradication.
The second half of 2015 saw the end of the Ebola epidemic, throughout which the polio team provided staff support, surveillance capacity, contact tracing, data and outbreak management, and logistical support. This is just one example of the polio legacy in action.
Financing the Endgame Plan
The midterm review by the Polio Oversight Board concluded that interruption of transmission would not occur in 2015 and that a further US$ 1.5 billion would be required to fully implement the Endgame Plan.
Looking to the future
Progress in the second half of 2015 was strong and continues to justify cautious optimism.
Africa has been polio-free for a year. Surveillance systems remain essential to monitor and stop outbreaks. The absence of wild poliovirus type 3 (WPV3) since November 2012 increases confidence that WPV3 transmission has been stopped, leaving only WPV1. On entering 2016, the GPEI is shifting focus onto four key areas:
accelerating emergency measures to overcome the remaining obstacles in reaching all missed children with the polio vaccine;
continuing the introduction of at least one dose of IPV in the routine immunization schedule of all OPV-using countries;
intensifying efforts to monitor the switch from tOPV to bOPV;
ensuring sensitive polio surveillance and continuing to strengthen routine immunization systems to ensure high levels of immunity, particularly in high-risk areas.