Acute Flaccid Paralysis Surveillance Research Articles

Evaluation of acute flaccid paralysis surveillance performance before and during the 2014-2015 Ebola virus disease outbreak in Guinea and Liberia.

the number of wild poliomyelitis cases, worldwide, dropped from 350,000 cases in 1988 to 33 in 2018. Acute flaccid paralysis (AFP) surveillance is a key strategy toward achieving global polio eradication. The 2014 Ebola virus disease (EVD) epidemic in West Africa infected over 28,000 people and had devastating effects on health systems in Guinea, Liberia, and Sierra Leone. We sought to assess the effects of the 2014 Ebola outbreak on AFP surveillance in Guinea and Liberia. a retrospective cross-sectional analysis was performed for Guinea and Liberia to evaluate EVD´s impact on World Health Organization (WHO) AFP surveillance performance indicators during 2012-2015. both Guinea and Liberia met the WHO target non-polio AFP incidence rate nationally, and generally sub-nationally, prior to the EVD outbreak; rates decreased substantially during the outbreak in seven of eight regions in Guinea and 11 of 15 counties in Liberia. Throughout the study period, both Guinea and Liberia attained appropriate overall targets nationally for "notification" and "stool adequacy" indicators, but each country experienced periods of poor regional/county-specific indicator performance. these findings mirrored the negative effect of the Ebola outbreak on polio elimination activities in both countries and highlights the need to reinforce this surveillance system during times of crisis.

Innovative strategies developed to mitigate the impact of COVID-19 pandemic on polio surveillance in Nigeria, 2020.

following the spread of the COVID-19 pandemic to Nigeria, the Federal Government of Nigeria restricted human and vehicular movements to curb the spread of the disease. This action had a negative impact on Acute Flaccid Paralysis (AFP) surveillance, with a resultant reduction in the number of AFP cases reported. This paper describes the impact of the COVID-19 pandemic on poliovirus surveillance in Nigeria and the proactive interventions by Nigeria´s polio program to mitigate the impact of COVID-19 on polio surveillance. nine innovative strategies were implemented in all 774 Local Government Areas (LGA) of the 36 states and Federal Capital Territory (FCT) of the country. These strategies were developed by the national surveillance officers and operationalized by sub-national surveillance officers with different strategies starting at different epidemiological weeks from week 14 to 23, 2020. Many of the strategy innovations were technology-based and included: the use of mobile phones to send the AFP case definition and video by WhatsApp or by SMS, the use of state-specific toll-free numbers and Mobile Telephone Network (MTN) (mobile service provider) CallerfeelTM to community informants (CI) who were the main targets of the interventions to increase case detection and reporting. Others included the use of abridged e-surveillance integrated supportive supervision (ISS) checklists, virtual monthly DSNO meetings, and batched AFP stool specimen transportation network. compared to the same period in 2019, the cumulative rate of AFP case detection and reporting had gradually declined from 39.1% in January to 16.7% before the commencement of the interventions in week 20, 2020. However, the detection and reporting increased by 57.% from week 20 to week 47 compared to the same period in 2019. This is because with COVID-19, hospital visitation dropped, and the sick remained in the communities, so the CI network was relied on to detect and report AFP cases. The cumulative proportion of AFP cases reported by community informants as of week 47 increased from 13% in 2018 to 21% in 2020. This indicates an increase of 38%. Thirty-five AFP cases were detected and reported using the MTN Caller Feel strategy, while 15 cases were reported through state-specific toll-free numbers. the implementation of the innovative strategies was able to mitigate the low AFP case detection and reporting observed at the initial stage of the COVID-19 pandemic. The use of technology facilitated reaching the CI network, which was more instrumental in detecting and reporting the cases.

Providing information for decision-making in the Nigerian Polio Eradication Program, 2016-2020.

Nigeria made a coordinated effort to be certified by the World Health Organization's African Region for interrupting endemic transmission of wild poliovirus type-1 (WPV1) in August 2020 as a response to the resurgence of WPV1 cases in August 2016 after going two years without a case. The NEOC Data Working Group (DWG) was instrumental in providing quality and timely surveillance and campaign information for decision-making in order to interrupt WPV1 transmission and provide data toward documentation of its elimination for regional certification. The polio pre-campaign dashboard was used to assess the level of preparedness for Oral Poliovirus Vaccine (OPV) polio supplementary immunization activities (SIA) at three weeks, two weeks, one week, and three days to the start of each campaign implemented during 2016-2020. The administrative tally sheet, independent monitoring survey, and Lot Quality Assurance Sampling (LQAS) survey data collected and shared from the implementation level were analyzed by the EOC DWG to provide information by person, place, and time. Using a 90% threshold in LQAS surveys defining quality SIAs, the proportion of Local Government Areas (LGAs) in Nigeria's states in which post-SIA LQAS surveys were conducted that met this threshold were assessed over time. The highest level of preparedness attained by 3 days to a polio campaign during August 2016-February 2020 was 95% and the lowest attained was 77%. The admin, independent monitoring, and LQAS data analysis results were given to EOC working groups for assessing the performance and quality of each campaign. Twenty-twenty five percent of LGAs that failed LQAS were identified for repeat vaccination. Further, acute flaccid paralysis and environmental surveillance data and laboratory results were analyzed and shared with NEOC and partners. The government and partners used the information generated by the Data Working Group to take evidence-based action including determining the scope of the polio campaign, intensification of surveillance and routine immunization activities, and special intervention activities. On average, 12% of the 774 LGAs were identified as polio high risk LGAs for intervention using selected surveillance, routine immunization (RI), SIAs, and other relevant data sets. National Emergency Operation Centre Data Working Group provided quality and timely information that supported decision-making processes for the polio program in Nigeria. The quality and timely information enabled the NEOC to make evidence-based and timely decisions that contributed to gap identification and decision-making.

Acute Flaccid Paralysis in Australian Children from 2007 to 2017

Introduction: Acute flaccid paralysis (AFP) surveillance continues globally as part of the World Health Organization’s goal to eradicate poliomyelitis. The Australian Paediatric Surveillance Unit (APSU), Paediatric Active Enhanced Disease Surveillance (PAEDS) network, and National Enterovirus Reference Laboratory (NERL) collaborate in AFP surveillance in Australia, capturing and reviewing cases of AFP for all aetiologies in order to exclude poliovirus. We aimed to describe the AFP epidemiology in childhood over an 11 year period. Methods: Data were reported nationally by paediatricians via prospective APSU surveillance, PAEDS surveillance nurses at five tertiary paediatric hospitals and NERL from 2007 to 2017. Children aged 0–15 years with AFP were included. We combined APSU, PAEDS, and NERL datasets, analysed epidemiological trends, and described clinical features and investigations for major diagnoses. Results: Of 590 AFP-compatible cases, 49% were male; 47% were aged 0–4 years, 9% aged <1 year. Annual incidence of AFP was 1.3 cases per 100,000 children aged <15 years. Lower limb paralysis was the most frequent presenting symptom. The most frequent diagnoses were Guillain-Barre syndrome (GBS; 36%), transverse myelitis (TM; 17%), and acute disseminated encephalomyelitis (ADEM; 15%). No secular trend was seen in frequency of AFP cases nor amongst major diagnoses. Seasonality was observed with ADEM occurring more frequently in winter. We observed periods of increased AFP frequency in 2013 and 2016, coinciding with increased reporting of non-polio anterior horn cell disease (AHCD) and detection of non-polio enterovirus (NPEV). Conclusions: Estimated incidence of GBS, ADEM, and TM in Australian children was comparable with international rates. There was stable incidence of AFP in Australian children between 2007 and 2017. GBS, ADEM, and TM are the major causes of AFP. We observed clustering of cases associated with NPEV that emphasises a need for ongoing vigilance in surveillance given continue emerging infectious disease threats.

Australian Paediatric Surveillance Unit (APSU) Annual Surveillance Report 2021.

The Australian Paediatric Surveillance Unit (APSU) has been conducting surveillance of rare communicable and non-communicable conditions in children since its inception in 1993. In this report, the results are described of surveillance of ten communicable diseases (and complications) for 2021, including the numbers of cases and incidence estimates; demographics; clinical features; and management and short-term outcomes. The included diseases are: acute flaccid paralysis (AFP); congenital cytomegalovirus (CMV); neonatal herpes simplex virus (HSV) infection; paediatric human immunodeficiency virus (HIV) infection; perinatal exposure to HIV; severe complications from influenza; juvenile-onset respiratory papillomatosis (JoRRP); congenital rubella syndrome; congenital varicella syndrome; and neonatal varicella infection. In 2021, cases of JoRRP were reported to the APSU for the first time since 2017, indicating potential gaps in HPV vaccination. AFP surveillance by APSU again contributed to Australia achieving a minimum target incidence of one AFP case per 100,000 children aged < 15 years. There were no cases of children with severe complications of influenza. No cases of varicella or congenital rubella were reported; however, at-risk populations, especially young migrant and refugee women from countries without universal vaccination programs, need to be screened and prioritised for vaccination prior to pregnancy. Cases of perinatal exposure to HIV continue to increase; however, the rate of mother-to-child-transmission remains at low levels due to the use of effective intervention strategies. Case numbers of congenital CMV and neonatal HSV remain steady in the absence of vaccines, prompting the need for greater awareness and education, with recent calls for target screening of at-risk infants for congenital CMV.

Poliomyelitis Outbreak in Papua New Guinea, 2018

Objective: Vaccine-derived poliovirus (VDPV) remains a significant barrier to global poliomyelitis eradication. Following 18 years of polio-free status, an epidemic of circulating VDPV type 1 (cVDPV1) occurred in Papua New Guinea (PNG) in 2018. We describe the epidemiology of the 2018 cVDPV1 epidemic in PNG, and identify risk factors which may aid future policy and control efforts.Methods: Data pertaining to the 2018 PNG epidemic were extracted from EPIWATCH and supplemented with data from other sources, such as the World Health Organization (WHO), and published literature. Descriptive analyses were undertaken, and key risk factors identified.Results: 26 cases of cVDPV1 were confirmed throughout the duration of the epidemic (April to October 2018) in nine provinces. Of the 26 cases, 19 (73%) were males and 7 (27%) were females, and most of the cases (73%) occurred in children under the age of five. Population immunization coverage of three doses of oral polio vaccine (OPV3) was found to fluctuate between 60- 80% between 2000 and 2018. Nonpolio Acute Flaccid Paralysis (NPAFP) surveillance rates were also found to be suboptimal over this period.Discussion: A combination of low routine immunization coverage, lacking supplementary immunization activities, and ineffective surveillance systems, in the context of a struggling health system, culminated in this epidemic. To prevent future poliomyelitis epidemics in PNG, emphasis must be placed on supporting the health system to maintain high vaccination coverage, in conjunction with robust and effective surveillance systems.

Enterovirus species B isolates recovered from children with acute flaccid paralysis in Nigeria, 2010 and 2012

In 2010 and 2012, between June and October (the peak period of enterovirus circulation in Nigeria), 59 archived enterovirus isolates (recovered as part of the Acute Flaccid Paralysis surveillance program) were randomly selected and typed in this study. All isolates were subjected to RNA extraction, cDNA synthesis and VP1 amplification (nested) and sequencing. Of the 59 isolates, 45 (21 and 24 of the isolates from 2010 to 2012, respectively) had the expected band size (∼350 bp). Forty-three (43) (19 and 24 from 2010 to 2012, respectively) of the amplicons generated were successfully identified and all typed as Enterovirus species B (EV-B) members belonging to twenty (20) different types. The most commonly detected were Echovirus 11 (E11) (9 isolates) and E30 (4 isolates). Many EV-B clades detected show evidence of cross-border transmission in humans within Africa and international spread. Evidence of possible zooanthroponosis/anthropozoonosis between human and nonhuman primates in one EV-B lineage is also reported.

Evolutionary phylogeography reveals novel genotypes of coxsackievirus A24 variant and updates the spatiotemporal dynamics in the population with acute hemorrhagic conjunctivitis

ObjectivesThe coxsackievirus A24 variant (CVA24v) has raised a remarkable concern because of its main etiological role in acute hemorrhagic conjunctivitis. MethodsWe conducted a retrospective study to summarize CVA24v isolated from acute hemorrhagic conjunctivitis outbreaks and acute flaccid paralysis surveillance in Shandong province, China during 1988-2020. Phylogenetic and phylogeographic methods based on the VP1 coding region were used to determine the CVA24v origin, spatiotemporal dynamics, and evolution. Also, the positive selection sites in the VP1 gene were identified and exhibited in the tertiary structure. ResultsThe global CVA24vs were classified into eight genotypes (GⅠ-GⅧ). Here, 12 CVA24v isolates were detected, of which five strains were typed as two novel genotypes (GⅦ and GⅧ) and reported first in the world. The time to the most recent common ancestor of the global CVA24v was estimated around March 1965 and evolved with 5.573 × 10−3 substitutions/site/year. Four residues under positive selection were detected, and residue 146T might be adapted in the CVA24v pandemic. Phylogeographic analysis indicated that China was the main source sink for CVA24v dispersion in a long-lasting global pattern. ConclusionOur study updated the epidemiological characteristics of CVA24v and enabled a better understanding of the molecular mechanism underlying different genotypes. The results provided new insights into the CVA24v origin, spatiotemporal dynamics, and possibly, the determinants of viral tropism and pathogenicity.

Importation and Circulation of Vaccine-Derived Poliovirus Serotype 2, Senegal, 2020-2021.

Environmental surveillance for poliovirus is increasingly used in poliovirus eradication efforts as a supplement to acute flaccid paralysis (AFP) surveillance. Environmental surveillance was officially established in 2017 in Senegal, where no poliovirus had been detected since 2010. We tested sewage samples from 2 sites in Dakar monthly for polioviruses. We identified a vaccine-derived poliovirus serotype 2 on January 19, 2021, from a sample collected on December 24, 2020; by December 31, 2021, we had detected 70 vaccine-derived poliovirus serotype 2 isolates circulating in 7 of 14 regions in Senegal. Sources included 18 AFP cases, 20 direct contacts, 17 contacts in the community, and 15 sewage samples. Phylogenetic analysis revealed the circulation of 2 clusters and provided evidence on the virus introduction from Guinea. Because novel oral polio vaccine serotype 2 was used for response activities throughout Senegal, we recommend expanding environmental surveillance into other regions.

Vaccine-associated paralytic poliomyelitis in a child: fast transformation from Sabin-like virus to vaccine-derived poliovirus triggered an epidemiological response in two countries of the European region

ObjectivesThe detection of a vaccine-derived poliovirus (VDPV) requires an epidemiological assessment and response. Using repeated stool sampling from a child who is immunocompetent and was vaccinated against poliomyelitis with acute flaccid paralysis, a case of an extremely rapid evolution of Sabin-like poliovirus (PV) type 3 was traced in the child's body. MethodsThe case was independently identified in two countries—Tajikistan and Russia. Stool samples for the study were also independently collected in two countries on different days from the onset of paralysis. Virological, serological, and molecular methods; full genome Sanger; and high-throughput sequencing were performed to characterize isolates. ResultsPV isolates from samples collected on days 2, 3, and 14 contained eight, seven, and seven mutations in the VP1-coding region, respectively, and were classified as Sabin-like PV type 3. The isolates from samples collected on days 15 and 18 had 11 mutations and were classified as vaccine-derived PVs, which required an epidemiological response in the two countries. ConclusionThe results indicate the need to continue acute flaccid paralysis surveillance, maintain high vaccination coverage, and develop and introduce new effective, genetically stable PV vaccines.

Various presentations of Guillain-Barre syndrome-a case series

Guillain-Barre syndrome (GBS) is a common differential diagnosis for acute flaccid paralysis. It is a notifiable condition in India under acute flaccid paralysis (AFP) surveillance. The presentations can be of varying severity with or without respiratory involvement. Intravenous immunoglobulin (IvIgG) is given to arrest the progression of disease.

Trends of key surveillance performance indicators of acute flaccid paralysis: a descriptive analysis, Uganda, 2015–2020

BackgroundPolio is disease caused by poliovirus which can in turn cause irreversible paralytic disease, presenting as Acute Flaccid Paralysis (AFP). A sensitive AFP surveillance system, in which all reported AFP cases are evaluated, first to determine if they are true AFP cases or not, is key for tracking polio eradication. True AFP cases are then later categorized as polio AFP or non-polio AFP (NPAFP) cases. Sensitivity is defined by meeting an annual NPAFP rate/100,000 population < 15 years of ≥ 4/100,000, and an annual stool adequacy (SA) rate of ≥ 80%. We describe Uganda’s AFP surveillance performance between 2015–2020, based on the WHO-recommended indicators, including; NPAFP and stool adequacy rate.MethodsWe performed a descriptive analysis of national AFP surveillance data, 2015–2020 obtained from ministry of health. We evaluated proportion of reported AFP cases that were true AFP, and changes in NPAFP and stool adequacy (SA) rate over the study period. We evaluated the trends in achieving the targeted NPAFP and SA rates from 2015–2020. We used QGIS to illustrate patterns in NPAFP and SA rates across districts and subregions.ResultsAmong 3,605 AFP cases reported and investigated countrywide from 2015–2020, 3,475 (96%) were true AFP cases. All the true AFP cases were non-polio related. District reporting was near-complete (97–100% each year). Overall, the mean NPAFP rate declined from 3.1/100,000 in 2015 to 2.1/100,000 in 2020. Less than 40% of districts met the NPAFP target rate in all years. The proportion of districts achieving the NPAFP target rate of ≥ 4/100,000 significantly declined from 35% in 2015 to 20% in 2020. The mean annual SA rate nationally was 88% from 2015–2020. Only 66% of districts achieved the SA target rate of ≥ 80% in the study period. The proportion of districts with SA rate ≥ 80% significantly increased from 68 to 80% between 2015 and 2020.ConclusionMost districts reported AFP cases. However, there was a decline in the NPAFP rate from 2015–2020 and few districts achieved the target rate. The suboptimal AFP surveillance system performance leaves the country at risk of missing ongoing poliovirus transmission. We recommend health worker training on active AFP searches, intensified supportive supervision, increase the number of environmental surveillance sentinel sites to boost AFP surveillance in the country, and periodic review meetings with districts to assess AFP surveillance performance.

Detecting Early Hepatocellular Carcinoma in Patients With Chronic Hepatitis B Using Longitudinal α-Fetoprotein Screening

This study aimed to evaluate the parametric empirical Bayes (PEB) longitudinal α-fetoprotein (AFP) screening algorithm performance in patients with hepatitis B compared with AFP surveillance with a fixed threshold. The serum AFP of 588 patients was measured. Patients were screened at least once every 6 months with AFP and ultrasound or computed tomography/magnetic resonance imaging. Age, aspartate aminotransferase level, alanine aminotransferase level, platelet count, total bilirubin, prothrombin time, and hepatitis B virus DNA level were adjusted in the PEB algorithm. All variables were abstracted at the time of hepatocellular carcinoma (HCC) diagnosis for cases or last follow-up for controls and at months -6, -12, -18, -24, -30, -36, -42, -48, and -54, up to month -60. Overall, 62 (10.5%) HCC cases developed during a median follow-up of 52.7 months. Moreover, 55 (88.7%) cases were detected at Barcelona Clinic Liver Cancer stage 0 or A. The area under the receiver-operating characteristic curve of the patient-level true positive rate against the screening-level false positive rate was significantly higher in the PEB algorithm than that in AFP alone (area under the receiver-operating characteristic curve: 0.94 vs 0.86; P < .0005). At 80% specificity, the PEB algorithm significantly improved the patient-level true positive rate within 2 years prior to HCC diagnosis compared with AFP alone (80.6% vs 67.7%, respectively; P= .0485; adjusted P= .1663). The PEB algorithm more effectively enabled first positive screening. The longitudinal assessment of AFP by the PEB algorithm improved HCC screening performance compared to AFP alone in patients with hepatitis B. This algorithm may improve HCC screening without additional cost or inconvenience to patients.

CaFÉ: A Sensitive, Low-Cost Filtration Method for Detecting Polioviruses and Other Enteroviruses in Residual Waters.

Acute flaccid paralysis (AFP) surveillance has been used to identify polio cases and target vaccination campaigns since the inception of the Global Poliovirus Eradication Initiative (GPEI) in 1988. To date, only Afghanistan and Pakistan have failed to interrupt wild poliovirus transmission. Circulation of vaccine-derived polioviruses (VDPV) continues to be a problem in high-risk areas of the Eastern Mediterranean, African, and Southeast Asian regions. Environmental surveillance (ES) is an important adjunct to AFP surveillance, helping to identify circulating polioviruses in problematic areas. Stools from AFP cases and contacts (>200,000 specimens/year) and ES samples (>642 sites) are referred to 146 laboratories in the Global Polio Laboratory Network (GPLN) for testing. Although most World Health Organization supported laboratories use the two-phase separation method due to its simplicity and effectiveness, alternative simple, widely available, and cost-effective methods are needed. The CAFÉ (Concentration and Filtration Elution) method was developed from existing filtration methods to handle any type of sewage or residual waters. At $10-20 US per sample for consumable materials, CAFÉ is cost effective, and all equipment and reagents are readily available from markets and suppliers globally. The report describes the results from a parallel study of CAFÉ method with the standard two-phase separation method. The study was performed with samples collected from five countries (Guatemala, Haïti, Thailand, Papua New Guinea, and the Philippines), run in three laboratories-(United States, Thailand and in the Philippines) to account for regional and sample-to-sample variability. Samples from each site were divided into two 500 ml aliquots and processed by both methods, with no other additional concentration or manipulation. The results of 338 parallel-tested samples show that the CAFÉ method is more sensitive than the two-phase separation method for detection of non-polio enteroviruses (p-value < 0.0001) and performed as well as the two-phase separation method for polioviruses detection with no significant difference (p-value > 0.05). The CAFÉ method is a robust, sensitive, and cost-effective method for isolating enteroviruses from residual waters.

Modeling undetected live type 1 wild poliovirus circulation after apparent interruption of transmission: Pakistan and Afghanistan.

Since 2013, wild poliovirus (WPV) transmission occurred only for type 1 (WPV1). Following several years of increasing reported incidence (2017-2019) and programmatic disruptions caused by COVID-19 (early 2020), Pakistan and Afghanistan performed a large number of supplementary immunization activities (late 2020-2021). This increased intensity of immunization, following widespread transmission, substantially decreased WPV1 cases and positive environmental samples during 2021. Modeling the potential for undetected circulation of WPV1 after apparent interruption can support regional and global decisions about certification of the eradication of indigenous WPV1 transmission. We apply a stochastic model to estimate the confidence about no circulation (CNC) of WPV1 in Pakistan and Afghanistan as a function of time since the last reported case and/or positive environmental sample. Exploration of different assumptions about surveillance quality suggests a range for CNC for WPV1 as a function of time since the last positive surveillance signal, and supports the potential use of a time with no evidence of transmission of less than 3 years as sufficient to assume die out in the context of good acute flaccid paralysis (AFP) surveillance. We show high expected CNC based on AFP surveillance data alone, even with imperfect surveillance and some use of inactivated poliovirus vaccine masking the ability of AFP surveillance to detect transmission. Ensuring high quality AFP and environmental surveillance may substantially shorten the time required to reach high CNC. The time required for high CNC depends on whether immunization activities maintain high population immunity and the quality of surveillance data.

Genetic Characterization of Novel Oral Polio Vaccine Type 2 Viruses During Initial Use Phase Under Emergency Use Listing - Worldwide, March-October 2021.

The emergence and international spread of neurovirulent circulating vaccine-derived polioviruses (cVDPVs) across multiple countries in Africa and Asia in recent years pose a major challenge to the goal of eradicating all forms of polioviruses. Approximately 90% of all cVDPV outbreaks are caused by the type 2 strain of the Sabin vaccine, an oral live, attenuated vaccine; cVDPV outbreaks typically occur in areas of persistently low immunization coverage (1). A novel type 2 oral poliovirus vaccine (nOPV2), produced by genetic modification of the type 2 Sabin vaccine virus genome (2), was developed and evaluated through phase I and phase II clinical trials during 2017-2019. nOPV2 was demonstrated to be safe and well-tolerated, have noninferior immunogenicity, and have superior genetic stability compared with Sabin monovalent type 2 (as measured by preservation of the primary attenuation site [domain V in the 5' noncoding region] and significantly lower neurovirulence of fecally shed vaccine virus in transgenic mice) (3-5). These findings indicate that nOPV2 could be an important tool in reducing the risk for generating vaccine-derived polioviruses (VDPVs) and the risk for vaccine-associated paralytic poliomyelitis cases. Based on the favorable preclinical and clinical data, and the public health emergency of international concern generated by ongoing endemic wild poliovirus transmission and cVDPV type 2 outbreaks, the World Health Organization authorized nOPV2 for use under the Emergency Use Listing (EUL) pathway in November 2020, allowing for its first use for outbreak response in March 2021 (6). As required by the EUL process, among other EUL obligations, an extensive plan was developed and deployed for obtaining and monitoring nOPV2 isolates detected during acute flaccid paralysis (AFP) surveillance, environmental surveillance, adverse events after immunization surveillance, and targeted surveillance for adverse events of special interest (i.e., prespecified events that have the potential to be causally associated with the vaccine product), during outbreak response, as well as through planned field studies. Under this monitoring framework, data generated from whole-genome sequencing of nOPV2 isolates, alongside other virologic data for isolates from AFP and environmental surveillance systems, are reviewed by the genetic characterization subgroup of an nOPV working group of the Global Polio Eradication Initiative. Global nOPV2 genomic surveillance during March-October 2021 confirmed genetic stability of the primary attenuating site. Sequence data generated through this unprecedented global effort confirm the genetic stability of nOPV2 relative to Sabin 2 and suggest that nOPV2 will be an important tool in the eradication of poliomyelitis. nOPV2 surveillance should continue for the duration of the EUL.

Contribution of Auto-Visual AFP Detection and Reporting (AVADAR) on polio surveillance in South Sudan.

Introductionthe last wild polio virus in South Sudan was documented in 2009. Nonetheless, it was one of the last four countries in the WHO African region to be accepted as a polio-free country in June 2020. In line with this, to accelerate the polio-free documentation process, the country has piloted Auto Visual AFP Detection and Reporting (AVADAR) in three counties. This study examined the contribution of the AVADAR surveillance system to the traditional Acute Flaccid Paralysis (AFP) surveillance system to document lessons learnt and best practices.Methodswe performed a retrospective descriptive quantitative study design to analyze secondary AVADAR surveillance data collected from June 2018 to December 2019 and stored at the WHO AVADAR server.Resultsthe AVADAR community surveillance system has improved the two main AFP surveillance indicators in the piloted counties and made up 86% of the total number of true AFP cases detected in these counties. The completeness and timeliness of weekly zero reporting were 97% and 94%, respectively and maintained above the standard throughout the study, while the two main surveillance indicators in the project area were improved progressively except for the Gogrial West County. In contrast, main surveillance indicators declined in some of the none-AVADAR implementing counties.Conclusionthe AVADAR surveillance system can overcome the logistical and remoteness barriers that can hinder the early detection and reporting of cases due to insecurity, topographical, and communication barrier in rural and hard-to-reach areas to accomplish and sustain the two main surveillance indicators, along with the completeness and timeliness of weekly zero reporting. We recommend extending this application-based surveillance system to other areas with limited resources and similar challenges by incorporating other diseases of public health concern.

South Africa regains polio-free status: Processes involved and lessons learnt

The World Health Organization recommends continuous immunisation coverage and polio surveillance standards for countries to sustain a polio-free status. We highlight experiences and lessons learnt by South Africa (SA) in losing – and subsequently regaining – its polio-free status. Following some decline in achieving acute flaccid paralysis surveillance and immunisation coverage targets, SA had its polio-free status withdrawn in 2017. Existing gaps were addressed and the polio-free status was regained in 2019. Lessons learnt from this experience include reaffirming the importance of continued commitment to polio eradication efforts, strengthening health systems through quality improvement projects, ensuring accountability in supervision, and monitoring of polio-related indicators. Consistent political commitment, collaboration and accountability are critical in sustaining the country’s health programmes, including maintaining a polio-free status and closing identified gaps.

The sensitivity of acute flaccid paralysis surveillance - the case of South Sudan: retrospective secondary analysis of AFP surveillance data 2014-2019.

IntroductionSouth Sudan has made quite impressive progress in interrupting wild poliovirus and maintaining a polio-free status since the last case was reported in 2009. South Sudan introduced different complementary strategies to enhance acute flaccid paralysis (AFP) surveillance. Hence, the objective of this study is to evaluate the sensitivity of the surveillance system using the WHO recommended surveillance standard and highlight the progress and challenges over the years.Methodswe conducted a retrospective, descriptive, quantitative study design and used the available secondary AFP surveillance database.Resultsthe overall non-polio AFP rate was 6.2/100,000 children under 15 years old in the study period. The stool adequacy was maintained well above the certification level of surveillance. The two main surveillance performance indicators were met at the national level throughout the study period. In contrast, only five out of ten states persistently attained and maintained the two main surveillance performance indicators throughout the study period, while in 2019 all states achieved except for Jonglei state. During the analysis period, no wild poliovirus was isolated except two circulating Vaccine Derived Poliovirus Type 2 (cVDPV2) cases in 2014 and one Immunodeficiency Vaccine Derived Poliovirus Type 2 (iVDPV2) case in 2015. However, on average, three cases were classified as polio compatible with each year of the study.ConclusionSouth Sudan met the two key surveillance performance indicators and had a sensitive AFP surveillance system during the period studied. We recommend intensifying surveillance activities in the former conflict-affected states and counties to maintain polio-free status.

Acute flaccid paralysis surveillance performance from 2011 to 2020 in Jonglei State, South Sudan: progress and challenges encountered.

IntroductionSouth Sudan reported the last indigenous wild poliovirus (WPV) in 2001 in Unity State, while the country was part of Sudan. In addition, the country reported an imported case of WPV in 2004-2005 and 2008-2009. The WPV circulation in the state was interrupted in 2009 and the last case was reported in Ayod county. The country continues to be at risk of importation of circulating vaccine-derived poliovirus type 2 (cVDPV2). In 2014 and 2020 the country experienced an outbreak of cVDPV2, in which Jonglei state was one of the affected states. Four out of 50 (8%) cVDPV2 cases in 2020 were reported from Jonglei State. The purpose of this study is to review surveillance performance indicators of Jonglei and compare them with the WHO surveillance performance standard and other country´s surveillance performances.Methodsretrospective secondary data analysis was conducted using the Jonglei state Acute Flaccid Paralysis (AFP) surveillance case-based database from 2011 to 2020. The reason for selecting Jonglei is because it is one of the poor performing states and is chronically hit by flood and internal conflicts. Data analyses were carried out using the Microsoft Excel (2016) program, where descriptive analysis frequencies, tables, and graphs were generated.Resultsthe study revealed that 346 AFP cases were reported in the counties of Jonglei state from 2011 through 2020. Out of 11 counties, 11 (100%) of them have reported suspected AFP cases. Children under five years accounted for 275 (79%) of all cases. The male gender accounted for 175 (51%) of all cases. A total of 249 (72%) had received three or more doses of Oral Polio Vaccine (OPV). Non-Polio Acute Flaccid Paralysis (NPAFP) rate varies from 1.2 in 2014 to 4.4 cases per 100,000 children under 15 years in 2018. The stool adequacy ranges from 58% in 2020 to 100% in 2011.Conclusionthe performance of Jonglei´s AFP surveillance system did not meet the WHO recommended target for both major AFP surveillance indicators (non-polio AFP rate and stool adequacy) during the study period.