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In addition to affecting individual health the COVID-19 pandemic has disrupted efforts to deliver essential health services around the world. In this article we present an overview of the immediate programmatic and epidemiologic impact of the pandemic on polio eradication as well as the adaptive strategic and operational measures taken by the Global Polio Eradication Initiative (GPEI) from March through September 2020. Shortly after the World Health Organization (WHO) declared a global pandemic on 11 March 2020, the GPEI initially redirected the programme’s assets to tackle COVID-19 and suspended house-to-house supplementary immunization activities (SIAs) while also striving to continue essential poliovirus surveillance functions. From March to May 2020, 28 countries suspended a total of 62 polio vaccine SIAs. In spite of efforts to continue poliovirus surveillance, global acute flaccid paralysis (AFP) cases reported from January-July 2020 declined by 34% compared with the same period in 2019 along with decreases in the mean number of environment samples collected per active site in the critical areas of the African and Eastern Mediterranean regions. The GPEI recommended countries should resume planning and implementation of SIAs starting in July 2020 and released guidelines to ensure these could be done safely for front line workers and communities. By the end of September 2020, a total of 14 countries had implemented circulating vaccine-derived poliovirus type 2 (cVDPV2) outbreak response vaccination campaigns and Afghanistan and Pakistan restarted SIAs to stop ongoing wild poliovirus type 1 (WPV1) transmission. The longer-term impacts of disruptions to eradication efforts remain to be determined, especially in terms of the effect on poliovirus epidemiology. Adapting to the pandemic situation has imposed new considerations on program implementation and demonstrated not only GPEI’s contribution to global health security, but also identified potential opportunities for coordinated approaches across immunization and health services.

BACKGROUND Outbreaks of circulating vaccine-derived polioviruses (cVDPVs) pose a threat to the eventual eradication of all polioviruses. In 2017, an outbreak of cVDPV type 2 (cVDPV2) occurred in the midst of a war in Syria. We describe vaccination-based risk factors for and the successful response to the outbreak. METHODS We performed a descriptive analysis of cVDPV2 cases and key indicators of poliovirus surveillance and vaccination activities during 2016-2018. In the absence of reliable subnational coverage data, we used the caregiver-reported vaccination status of children with non-polio acute flaccid paralysis (AFP) as a proxy for vaccination coverage. We then estimated the relative odds of being unvaccinated against polio, comparing children in areas affected by the outbreak to children in other parts of Syria in order to establish the presence of poliovirus immunity gaps in outbreak affected areas. FINDINGS A total of 74 cVDPV2 cases were reported, with paralysis onset ranging from 3 March to 21 September 2017. All but three cases were reported from Deir-ez-Zor governorate and 84% had received

Pakistan and Afghanistan are the only countries where wild poliovirus type 1 (WPV1) is endemic (1,2). In 2019, Pakistan reported 147 WPV1 cases, approximately 12 times the number reported in 2018. As of September 15, 72 cases had been reported in 2020. Since 2019, WPV1 transmission has also spread from Pakistan's core poliovirus reservoirs (Karachi, Peshawar, and Quetta block) to southern districts of Khyber Pakhtunkhwa (KP), Punjab, and Sindh provinces. Further, an outbreak of circulating vaccine-derived poliovirus type 2 (cVDPV2), first detected in July 2019, has caused 22 paralytic cases in 2019 and 59 as of September 15, 2020, throughout the country. The coronavirus disease 2019 (COVID-19) pandemic has substantially reduced delivery of polio vaccines through essential immunization (formerly routine immunization) and prevented implementation of polio supplementary immunization activities (SIAs)* during March-July 2020. This report describes Pakistan's progress in polio eradication during January 2019-September 2020 and updates previous reports (1,3,4). The Pakistan polio program has reinitiated SIAs and will need large, intensive, high-quality campaigns with strategic use of available oral poliovirus vaccines (OPVs)† to control the surge and widespread transmission of WPV1 and cVDPV2.

Afghanistan and Pakistan are the only countries that continue to confirm ongoing wild poliovirus type 1 (WPV1) transmission (1). During January 2018-September 2019 the number of WPV1 cases in Pakistan increased, compared with the number during the previous 4 years. This report updates previous reports on Pakistan's polio eradication activities, progress, and challenges (2,3). In 2018, Pakistan reported 12 WPV1 cases, a 50% increase from eight cases in 2017, and a 31% increase in the proportion of WPV1-positive sites under environmental surveillance (i.e., sampling of sewage to detect poliovirus). As of November 7, 2019, 80 WPV1 cases had been reported, compared with eight cases by the same time in 2018. An intensive schedule of supplementary immunization activities (SIAs)* implemented by community health workers in the core reservoirs (i.e., Karachi, Peshawar, and Quetta) where WPV1 circulation has never been interrupted, and by mobile teams, has failed to interrupt WPV1 transmission in core reservoirs and prevent WPV1 resurgence in nonreservoir areas. Sewage samples have indicated wide WPV1 transmission in nonreservoir areas in other districts and provinces. Vaccine refusals, chronically missed children, community campaign fatigue, and poor vaccination management and implementation have exacerbated the situation. To overcome challenges to vaccinating children who are chronically missed in SIAs and to attain country and global polio eradication goals, substantial changes are needed in Pakistan's polio eradication program, including continuing cross-border coordination with Afghanistan, gaining community trust, conducting high-quality vaccination campaigns, improving oversight of field activities, and improving managerial processes to unify eradication efforts.

Widespread use of live attenuated (Sabin) oral poliovirus vaccine (OPV) has resulted in marked progress toward global poliomyelitis eradication (1). However, in underimmunized populations, extensive person-to-person transmission of Sabin poliovirus can result in genetic reversion to neurovirulence and paralytic vaccine-derived poliovirus (VDPV) disease (1). This report updates (as of February 26, 2019) previous reports on circulating VDPV type 2 (cVDPV2) outbreaks during 2017-2018 in the Democratic Republic of the Congo (DRC) and in Somalia, which experienced a concurrent cVDPV type 3 (cVDPV3) outbreak* (2,3). In DRC, 42 cases have been reported in four cVDPV2 outbreaks; paralysis onset in the most recent case was October 7, 2018 (2). Challenges to interrupting transmission have included delays in outbreak-response supplementary immunization activities (SIAs) and difficulty reaching children in all areas. In Somalia, cVDPV2 and cVDPV3 were detected in sewage before the detection of paralytic cases (3). Twelve type 2 and type 3 cVDPV cases have been confirmed; the most recent paralysis onset dates were September 2 (cVDPV2) and September 7, 2018 (cVDPV3). The primary challenge to interrupting transmission is the residence of >300,000 children in areas that are inaccessible for vaccination activities. For both countries, longer periods of surveillance are needed before interruption of cVDPV transmission can be inferred.

Introduction Circulation of poliovirus in neighboring countries and mass population movement places Lebanon at risk of polio and other vaccine-preventable disease outbreaks. Determining population immunity levels is essential for guiding program planning and implementation of targeted supplementary immunization activities (SIAs) in governorates and subpopulations with low seroprevalence. Methods A cross-sectional multi-stage cluster survey was conducted during February-December 2016 in all six governorates of Lebanon adapted from the World Health Organization (WHO) recommended Expanded Progamme on Immunization (EPI) methodology. Sera from selected children aged 12–59 months were tested for poliovirus neutralizing antibodies. Results Of 2,164 children recruited in this study, 1,893 provided sufficient quantity of serum samples for laboratory testing. Seroprevalence for all three poliovirus serotypes was greater than 90% in all six governorates. Poliovirus vaccine coverage with three or more doses, based on vaccination cards or parental recall, ranged between 54.1% for children aged 36–47 months in the North and 83.5% for children aged 48–59 months in Beirut. Conclusion Immunity to polioviruses was high in Lebanon in 2016 following a series of supplementary immunization activities. It is essential to continue strategies that increase vaccination coverage in order to sustain the considerably high immunity levels and prevent reintroduction and transmission of poliovirus. Educating caregivers and training health care workers on the standardized usage of home-based vaccination records is needed to guarantee the accuracy of records on children’s vaccination status.

Among the three wild poliovirus (WPV) serotypes, only WPV type 1 (WPV1) has been reported in polio cases or detected from environmental surveillance globally since 2012. Pakistan remains one of only three countries worldwide (the others are Afghanistan and Nigeria) that has never had interrupted WPV1 transmission. This report documents Pakistan's activities and progress toward polio eradication during January 2017-September 2018 and updates previous reports (1,2). In 2017, Pakistan reported eight WPV1 cases, a 60% decrease from 20 cases in 2016. As of September 18, 2018, four cases had been reported, compared with five cases at that time in 2017. Nonetheless, in 2018, WPV1 continues to be isolated regularly from environmental surveillance sites, primarily in the core reservoir areas of Karachi, Quetta, and Peshawar, signifying persistent transmission. Strategies to increase childhood immunity have included an intense schedule of supplemental immunization activities (SIAs), expanding and refining deployment of community-based vaccination implemented by community health workers recruited from the local community in reservoir areas, and strategic placement of permanent transit points where vaccination is provided to mobile populations. Interruption of WPV1 transmission will require further programmatic improvements throughout the country with a focus on specific underperforming subdistricts in reservoir areas.

Background To attain high coverage during polio vaccination campaigns, an outreach house-to-house strategy is used to administer oral poliovirus vaccine. Administering an injectable vaccine house-to-house requires a skilled work force and increases risks of needle stick injuries. Needle-free injection devices provide a safer alternative to needles and syringes for administering injectable vaccines. We evaluated the feasibility and acceptability of a needle-free injection device to administer injectable poliovirus vaccine during a house-to-house vaccination outreach activity. Methods Vaccination teams administered injectable poliovirus vaccine using the Pharmajet® needle-free intramuscular jet injector to children ages 6–59 months in 766 homes. Data on the feasibility of using the jet injector in an outreach campaign setting and the acceptability of the jet injector by caregivers and vaccinators were collected. Results A total of 993 injections were administered. Vaccinators faced challenges during device preparation in 16% (n = 158) of injections; challenges were related to problems loading the injector and not having a flat surface to use for setup of the injector. Among 32 vaccinators interviewed after the vaccination campaign, the main reported advantage of the device was absence of sharps disposal (91%) while the main reported disadvantage was unacceptability by parents (90%) which was related to the vaccine, not the device. Conclusions The needle-free jet injector was feasible for use in house-to-house campaigns. Acceptability by vaccinators was low as 81% stated that the jet injector was not easier to use than needle and syringe. Parental refusal related to frequent polio vaccination campaigns was the biggest challenge. In addition, novelty of the device posed a challenge to teams as they needed to reassure parents about safety of the device. To take full advantage of the ability to take injectable vaccines door-to-door during vaccination campaigns using a needle-free jet injector device, tailored social mobilization efforts are needed ahead of campaigns.

Since the 1988 inception of the Global Polio Eradication Initiative (GPEI), progress toward interruption of wild poliovirus (WPV) transmission has occurred mostly through extensive use of oral poliovirus vaccine (OPV) in mass vaccination campaigns and through routine immunization services (1,2). However, because OPV contains live, attenuated virus, it carries the rare risk for reversion to neurovirulence. In areas with very low OPV coverage, prolonged transmission of vaccine-associated viruses can lead to the emergence of vaccine-derived polioviruses (VDPVs), which can cause outbreaks of paralytic poliomyelitis. Although WPV type 2 has not been detected since 1999, and was declared eradicated in 2015,* most VDPV outbreaks have been attributable to VDPV serotype 2 (VDPV2) (3,4). After the synchronized global switch from trivalent OPV (tOPV) (containing vaccine virus types 1, 2, and 3) to bivalent OPV (bOPV) (types 1 and 3) in April 2016 (5), GPEI regards any VDPV2 emergence as a public health emergency (6,7). During May-June 2017, VDPV2 was isolated from stool specimens from two children with acute flaccid paralysis (AFP) in Deir-ez-Zor governorate, Syria. The first isolate differed from Sabin vaccine virus by 22 nucleotides in the VP1 coding region (903 nucleotides). Genetic sequence analysis linked the two cases, confirming an outbreak of circulating VDPV2 (cVDPV2). Poliovirus surveillance activities were intensified, and three rounds of vaccination campaigns, aimed at children aged

Due to security, access, and programmatic challenges in areas of Pakistan and Afghanistan, both countries continue to sustain indigenous wild poliovirus (WPV) transmission and threaten the success of global polio eradication and oral poliovirus vaccine (OPV) cessation. We fitted an existing differential-equation-based poliovirus transmission and OPV evolution model to Pakistan and Afghanistan using four subpopulations to characterize the well-vaccinated and undervaccinated subpopulations in each country. We explored retrospective and prospective scenarios for using inactivated poliovirus vaccine (IPV) in routine immunization or supplemental immunization activities (SIAs). The undervaccinated subpopulations sustain the circulation of serotype 1 WPV and serotype 2 circulating vaccine-derived poliovirus. We find a moderate impact of past IPV use on polio incidence and population immunity to transmission mainly due to (1) the boosting effect of IPV for individuals with preexisting immunity from a live poliovirus infection and (2) the effect of IPV-only on oropharyngeal transmission for individuals without preexisting immunity from a live poliovirus infection. Future IPV use may similarly yield moderate benefits, particularly if access to undervaccinated subpopulations dramatically improves. However, OPV provides a much greater impact on transmission and the incremental benefit of IPV in addition to OPV remains limited. This study suggests that despite the moderate effect of using IPV in SIAs, using OPV in SIAs remains the most effective means to stop transmission, while limited IPV resources should prioritize IPV use in routine immunization.

As the world advances toward the eradication of polio, outbreaks of wild poliovirus (WPV) in polio-free regions pose a substantial risk to the timeline for global eradication. Countries and regions experiencing active conflict, chronic insecurity, and large-scale displacement of persons are particularly vulnerable to outbreaks because of the disruption of health care and immunization services (1). A polio outbreak occurred in the Middle East, beginning in Syria in 2013 with subsequent spread to Iraq (2). The outbreak occurred 2 years after the onset of the Syrian civil war, resulted in 38 cases, and was the first time WPV was detected in Syria in approximately a decade (3,4). The national governments of eight countries designated the outbreak a public health emergency and collaborated with partners in the Global Polio Eradication Initiative (GPEI) to develop a multiphase outbreak response plan focused on improving the quality of acute flaccid paralysis (AFP) surveillance* and administering polio vaccines to >27 million children during multiple rounds of supplementary immunization activities (SIAs).† Successful implementation of the response plan led to containment and interruption of the outbreak within 6 months of its identification. The concerted approach adopted in response to this outbreak could serve as a model for responding to polio outbreaks in settings of conflict and political instability.

Background Despite insecurity challenges in Somalia, key indicators for acute flaccid paralysis (AFP) surveillance have met recommended targets. However, recent outbreaks of vaccine-derived polioviruses have raised concerns about possible gaps. We analyzed nonpolio enterovirus (NPEV) and Sabin poliovirus isolation rates to investigate whether comparing these rates can inform about the integrity of stool specimens from inaccessible areas and the likelihood of detecting circulating polioviruses. Methods Using logistic regression, we analyzed case-based AFP surveillance data for 1348 cases with onset during 2014−2017. We assessed the adjusted impacts of variables including age, accessibility, and Sabin-like virus isolation on NPEV detection. Results NPEVs were more likely to be isolated from AFP case patients reported from inaccessible areas than accessible areas (23% vs 15%; P = .01). In a multivariable model, inaccessibility and detection of Sabin-like virus were positively associated with NPEV detection (adjusted odds ratio [AOR], 1.75; 95% confidence interval [CI], 1.14–2.65; and AOR, 1.79; 95% CI, 1.07–2.90; respectively), while being aged ≥5 years was negatively associated (AOR, 0.42; 95% CI, 0.20–0.85). Conclusions Rates of NPEV and Sabin poliovirus detection in inaccessible areas suggest that the integrity of fecal specimens tested for AFP surveillance in Somalia can generate useful AFP data, but uncertainties remain about surveillance system quality.

A community-based serosurvey was conducted among children ages 6-59 to assess population immunity in Jordan's high-risk areas following the Middle East polio outbreak response. The survey was a two-stage cluster-quota sample with high risk areas as the primary sampling units. High-risk areas included border and hard-to-reach areas, and areas with a high proportion of refugees, mobile communities and/or low coverage during previous immunization campaigns. Population immunity to poliovirus was high overall. In high-risk areas, Type 1 seroprevalence = 98% (95% CI = 96, 99), Type 2 = 98% (95% CI = 96, 99) and Type 3 = 96% (95% CI = 94, 98). Seroprevalence was higher in the refugee camps: Type 1 seroprevalence = 99.6% (95% CI = 97.9, 100); Type 2: 99.6% (95% CI = 97.9, 99.9), and Type 3: 100% (95% CI = 100,100). The vigilance that the Jordan Ministry of Health has placed on locating and vaccinating high-risk populations has been successful in maintaining high population immunity and averting polio outbreaks despite the influx of refugees from Syria.

Since October 2016, Afghanistan and Pakistan have been the only countries with reported cases of wild poliovirus type 1 (WPV1) (1). In Afghanistan, although the number of cases had declined during 2013-2016, the polio eradication program experienced challenges during 2017-2019. This report describes polio eradication activities and progress in Afghanistan during January 2018-May 2019 and updates previous reports (2,3). During May-December 2018, insurgent groups (antigovernment elements) banned house-to-house vaccination in most southern and southeastern provinces, leaving approximately 1 million children inaccessible to oral poliovirus vaccine (OPV) administration. During January-April 2019, vaccination targeting children at designated community sites (site-to-site vaccination) was permitted; however, at the end of April 2019, vaccination campaigns were banned nationally. During 2018, a total of 21 WPV1 cases were reported in Afghanistan, compared with 14 during 2017. During January-May 2019, 10 WPV1 cases were reported (as of May 31), compared with eight during January-May 2018. Sewage sample-testing takes place at 20 sites in the highest-risk areas for poliovirus circulation; 17 have detected WPV1 since January 2017, primarily in the southern and eastern provinces. Continued discussion with antigovernment elements to resume house-to-house campaigns is important to achieving polio eradication in Afghanistan. To increase community support for vaccination, collaboration among humanitarian service agencies to address other urgent health and basic needs is critical.

Following the declaration of eradication of wild poliovirus (WPV) type 2 in September 2015, trivalent oral poliovirus vaccine (tOPV) was withdrawn globally to reduce the risk for type 2 vaccine-derived poliovirus (VDPV2) transmission; all countries implemented a synchronized switch to bivalent OPV (type 1 and 3) in April 2016 (1,2). Any isolation of VDPV2 after the switch is to be treated as a potential public health emergency and might indicate the need for supplementary immunization activities (3,4). On August 9, 2016, VDPV2 was isolated from a sewage sample taken from an environmental surveillance site in Hyderabad, Sindh province, Pakistan. Possible vaccination activities in response to VDPV2 isolation include the use of injectable inactivated polio vaccine (IPV), which poses no risk for vaccine-derived poliovirus transmission. Fractional-dose, intradermal IPV (fIPV), one fifth of the standard intramuscular dose, has been developed to more efficiently manage limited IPV supplies. fIPV has been shown in some studies to be noninferior to full-dose IPV (5,6) and was used successfully in response to a similar detection of a single VDPV2 isolate from sewage in India (7). Injectable fIPV was used for response activities in Hyderabad and three neighboring districts. This report describes the findings of an assessment of preparatory activities and subsequent implementation of the fIPV campaign. Despite achieving high coverage (>80%), several operational challenges were noted. The lessons learned from this campaign could help to guide the planning and implementation of future fIPV vaccination activities.

In 1988, the World Health Assembly launched the Global Polio Eradication Initiative. Among the three wild poliovirus serotypes, only wild poliovirus (WPV) type 1 (WPV1) has been detected since 2012. Since 2014, Pakistan, Afghanistan, and Nigeria remain the only countries with continuing endemic WPV1 transmission. This report describes activities conducted and progress made toward the eradication of poliovirus in Pakistan during January 2016-July 2017 and provides an update to previous reports (1,2). In 2016, Pakistan reported 20 WPV1 cases, a 63% decrease compared with 54 cases in 2015 (3). As of September 25, 2017, five WPV1 cases have been reported in 2017, representing a 69% decline compared with 16 cases reported during the same period in 2016 (Figure 1). During January-September 2017, WPV1 was detected in 72 of 468 (15%) environmental samples collected, compared with 36 of 348 (9%) samples collected during the same period in 2016. WPV1 was detected in environmental samples in areas where no polio cases are being reported, which indicates that WPV1 transmission is continuing in some high-risk areas. Interruption of WPV transmission in Pakistan requires maintaining focus on reaching missed children (particularly among mobile populations), continuing community-based vaccination, implementing the 2017-2018 National Emergency Action Plan (4), and improving routine immunization services.

Background Surveillance for cases of acute flaccid paralysis (AFP) is a key strategy adopted for the eradication of polio. Detection of poliovirus circulation is often predicated on the ability to identify AFP cases and test their stool specimens for poliovirus infection in a timely manner. The Village Polio Volunteers (VPV) program was established in 2013 in a bid to strengthen polio eradication activities in Somalia, including AFP surveillance, given the country's vulnerability to polio outbreaks. Methods To assess the impact of the VPV program on AFP surveillance, we determined case counts, case-reporting sources, and nonpolio AFP rates in the years before and after program introduction (ie, 2011-2016). We also compared the stool specimen adequacy rates and timeliness of cases reported by VPVs to those reported by other sources. Results In the years after program introduction, VPVs accounted for a high proportion of AFP cases reported in Somalia. AFP case counts rose from 148 cases in 2012, the year before program introduction, to 279 cases in 2015, when VPVs accounted for 40% of reported cases. Further, from 2012 to 2015, the nonpolio AFP rate improved from 2.8 to 4.8 cases per 100000 persons aged

Despite recent progress toward global polio eradication, endemic transmission of wild poliovirus (WPV) continues to be reported in Afghanistan and Pakistan. The Afghanistan program must overcome many challenges to remain on track toward achieving the objectives set in the 2013–2018 strategic plan of the Global Polio Eradication Initiative (GPEI). Cross-border transmission of WPV type 1 (WPV1) continues to occur among children traveling to and from Pakistan. The country's routine immunization system remains weak and unable to reach recommended benchmarks in most regions; hence, the national Polio Eradication Initiative (PEI) relies mainly on providing children aged

Background After the last case of type 1 wild poliovirus (WPV1) was reported in 2007, Somalia experienced another outbreak of WPV1 (189 cases) in 2013. Methods We conducted a retrospective, matched case-control study to evaluate the vaccine effectiveness (VE) of oral polio vaccine (OPV). We retrieved information from the Somalia Surveillance Database. A case was defined as any case of acute flaccid paralysis (AFP) with virological confirmation of WPV1. We selected two groups of controls for each case: non-polio AFP cases ("NPAFP controls") matched to WPV1 cases by age, date of onset of paralysis and region; and asymptomatic "neighborhood controls," matched by age. Using conditional logistic regression, we estimated the VE of OPV as (1-odds ratio)×100. Result We matched 99 WPV cases with 99 NPAFP controls and 134 WPV1 cases with 268 neighborhood controls. Using NPAFP controls, the overall VE was 70% (95% confidence interval [CI], 37-86), 59% (2-83) among 1-3 dose recipients, 77% (95% CI, 46-91) among ≥4 dose recipients. In neighborhood controls, the overall VE was 95% (95% CI, 84-98), 92% (72-98) among 1-3 dose recipients, and 97% (89-99) among ≥4 dose recipients. When the analysis was limited to cases and controls ≤24 months old, the overall VE in NPAFP and neighborhood controls was 95% (95% CI, 65-99) and 97% (95% CI, 76-100), respectively. Conclusions Among individuals who were fully vaccinated with OPV, vaccination was effective at preventing WPV1 in Somalia.

Pakistan, Afghanistan, and Nigeria remain the only countries where endemic wild poliovirus type 1 (WPV1) transmission continues. This report describes the activities, challenges, and progress toward polio eradication in Pakistan during January 2015-September 2016 and updates previous reports (1,2). In 2015, a total of 54 WPV1 cases were reported in Pakistan, an 82% decrease from 2014. In 2016, 15 WPV1 cases had been reported as of November 1, representing a 61% decrease compared with the 38 cases reported during the same period in 2015 (Figure 1). Among the 15 WPV1 cases reported in 2016, children aged

Since Nigeria reported its last case of wild poliovirus type 1 (WPV1) in July 2014, Pakistan and Afghanistan remain the only two countries where WPV transmission has never been interrupted. This report describes actions taken and progress achieved toward polio eradication in Pakistan during January 2014-September 2015 and updates previous reports. A total of 38 WPV1 cases were reported in Pakistan during January-September 2015, compared with 243 during the same period in 2014 (an 84% decline). Among WPV1 cases reported in 2015, 32 (84%) occurred in children aged

Since the 1988 resolution of the World Health Assembly to eradicate polio, significant progress has been made toward achieving this goal, with the result that only Afghanistan, Nigeria, and Pakistan have never successfully interrupted endemic transmission of wild poliovirus. However, one of the greatest challenges of the Global Polio Eradication Initiative has been that of maintaining the polio-free status of countries in unstable regions with weak healthcare infrastructure, a challenge exemplified by Somalia, a country in the Horn of Africa region. Somalia interrupted indigenous transmission of wild poliovirus in 2002, four years after establishing its national polio eradication programme. But political instability and protracted armed conflict, with significant disruption of the healthcare system, left the country vulnerable to two subsequent imported outbreaks of wild poliovirus. The first occurred during 2005–2007, resulting in over 200 cases of paralytic polio, while the second importation in 2013 is currently ongoing. Despite immense challenges, the country has a sensitive surveillance system that has facilitated prompt detection of outbreaks, but its weak routine immunization system means that supplementary immunization activities constitute the primary strategy for reaching children with polio vaccines. Conducting vaccination campaigns in a setting of conflict has been at times hazardous but the country’s polio programme has demonstrated resilience in overcoming many obstacles to ensure that children receive life-saving polio vaccines. Regaining and maintaining Somalia’s polio-free status will, however, depend on finding innovative and lasting solutions to the challenge of administering vaccines in a setting of ongoing conflict and instability.

In 2012, the World Health Assembly declared the completion of polio eradication a programmatic emergency for global public health and called for a comprehensive polio endgame strategy. Afghanistan and Pakistan are two of the three remaining countries (the other is Nigeria) where circulation of indigenous wild poliovirus (WPV) has never been interrupted. This report updates previous reports and describes polio eradication activities and progress in Afghanistan and Pakistan during January 2013-August 2014. In Afghanistan, 14 WPV cases were reported in 2013, compared with 37 cases in 2012; nine cases were reported during January-August 2014, compared with six cases during the same period in 2013. In Pakistan, 93 WPV cases were reported in 2013, compared with 58 cases in 2012; 170 cases were reported during January-August 2014, compared with 33 cases during the same period in 2013. All WPV cases reported during January 2013-August 2014 were WPV type 1 (WPV1). Vaccination campaigns have been banned since June 2012 in specific areas in Pakistan, where an estimated 300,000 children aged5 years reside and where 69% of WPV cases have occurred in 2014. To accomplish the objectives of the Polio Eradication and Endgame Strategic Plan for 2013-2018 both countries should continue to negotiate access of vaccinators to insecure and temporarily inaccessible areas, improve immunization program performance to reach more children in accessible areas, and ensure that political and health leaders at all levels are fully committed to the program, including being committed to providing financial resources needed to fully implement all the recommendations of external technical advisory groups. Both countries should also continue to strengthen cross-border collaboration to improve surveillance and case detection, coordinate outbreak response, and maximize vaccination coverage of children moving between the two countries.