Progress Toward Polio Eradication - Worldwide, January 2018-March 2020

High throughput AS LNA qPCR method for the detection of a specific mutation in poliovirus vaccine strains

Sabin Inactivated Poliovirus Vaccine (sIPV) has become one of the preferred vaccination options for the last step in the Poliovirus eradication program. Sequencing of poliovirus samples is needed during the manufacturing of poliovirus vaccines to assure the safety and immunogenicity of these vaccines. Next-generation sequencing analysis is the current costly and time-consuming gold standard for monitoring the manufacturing processes. We developed a low-cost and quick, highly sensitive, and allele-specific locked nucleic acid-probe-based reverse transcription quantitative PCR alternative that can accurately detect mutations in poliovirus vaccine samples during process development, scaling up, and release. Using the frequently in vitro occurring and viral replication-impacting VP1-E295K mutation as a showcase, we show that this technology can accurately detect E295K mutations in poliovirus 2 samples to similar levels as NGS. The qPCR technology was developed employing a synthetic dsDNA fragment-based standard curve containing mixes of E295K-WT (wildtype) and Mut (mutant) synthetic dsDNA fragments ranging from 1 × 107 copies/µL to 1 × 102 copies/µL to achieve a linear correlation with R2 > 0.999, and PCR efficiencies of 95-105 %. Individual standard concentration levels achieved accuracies of ≥92 % (average 96 %) and precisions of ≤17 % (average 3.3 %) RSD. Specificity of locked nucleic acid (LNA)-probes was confirmed in the presence and absence of co-mutations in the probe-binding region. Application of the developed assay to Sabin Poliovirus type 2 production run samples, illustrated a linear relationship with an R2 of 0.994, and an average accuracy of 97.2 % of the variant (allele)-specific AS LNA qPCR result, compared to NGS. The assay showed good sensitivity for poliovirus samples, containing E295K mutation levels between 0 % and 95 % (quantification range). In conclusion, the developed AS LNA qPCR presents a valuable low-cost, and fast tool, suitable for the process development and quality control of polio vaccines.

Exploring the path to polio eradication: insights from consecutive seroprevalence surveys among Pakistani children

Introduction

After trivalent oral poliovirus vaccine (tOPV) cessation, Pakistan has maintained immunity to type 2 poliovirus by administering inactivated polio vaccine (IPV) in routine immunization, alongside monovalent OPV type 2 (mOPV2) and IPV in supplementary immunization activities (SIAs). This study assesses the change in poliovirus type 2 immunity after tOPV withdrawal and due to SIAs with mOPV2 and IPV among children aged 6-11 months.

Methods

Three cross-sectional sequential serological surveys were conducted in 12 polio high-risk areas of Pakistan. 25 clusters from each geographical stratum were selected utilizing probability proportional to size.

Results

Seroprevalence of type 2 poliovirus was 49%, with significant variation observed among surveyed areas; <30% in Pishin, >80% in Killa Abdullah, Mardan & Swabi, and Rawalpindi. SIAs with IPV improved immunity from 38 to 57% in Karachi and 60 to 88% in Khyber. SIAs with IPV following mOPV2 improved immunity from 62 to 65% in Killa Abdullah, and combined mOPV2 and IPV SIAs in Pishin improved immunity from 28 to 89%. Results also reflected that immunity rates for serotypes 1 and 3 were consistently above 90% during all three phases and across all geographical areas.

Conclusion

The study findings highlight the importance of implementing effective vaccination strategies to prevent the re-emergence of poliovirus. Moreover, the results provide crucial information for policymakers working toward achieving global polio eradication.

Mothers' knowledge, attitude, and behavior regarding child immunization, and the association with child immunization status in Medan City during the COVID-19 pandemic

Background

The COVID-19 pandemic has caused disruption to healthcare access worldwide and has impacted basic childhood immunization services. A decline in immunization coverage can cause immunity gaps and lead to outbreaks of vaccine-preventable diseases. Our study evaluated the association between mothers' knowledge, attitude, and behavior regarding immunization and child immunization status during the COVID-19 pandemic in Medan, Indonesia.

Methods

An analytical cross-sectional study was conducted from April to November 2021. Mothers with children aged 0-12 months were interviewed about their knowledge, attitude, and behavior regarding immunization, and their child's immunization status.

Results

Of 196 participants, 46.5% had low knowledge on immunization, 41.3% had a negative attitude, and 20.4% had negative behavior. Only 62.8% of participants had children with a complete vaccination status, and mothers with moderate knowledge (OR 2.65, 95% CI 1.08-6.61), negative attitude (OR 5.33, 95% CI 2.71-10.59), and negative behavior (OR 7.88, 95% CI 3.36-19.47) were more likely to not vaccinate their children.

Conclusion

Mothers' attitude, behavior, and educational background were associated with child immunization status. Recovery efforts to improve immunization coverage are urgently needed, and should include efforts to reduce mothers' hesitancy regarding child vaccination during the pandemic.

Genetic and epidemiological description of an outbreak of circulating vaccine-derived polio-virus type 2 (cVDPV2) in Angola, 2019-2020

After six years without any detection of poliomyelitis cases, Angola reported a case of circulating vaccine-derived poliovirus type 2 (cVDPV2) with paralysis onset date of 27 March 2019. Ultimately, 141 cVDPV2 polio cases were reported in all 18 provinces in 2019-2020, with particularly large hotspots in the south-central provinces of Luanda, Cuanza Sul, and Huambo. Most cases were reported from August to December 2019, with a peak of 15 cases in October 2019. These cases were classified into five distinct genetic emergences (emergence groups) and have ties with cases identified in 2017-2018 in the Democratic Republic of Congo. From June 2019 to July 2020, the Angola Ministry of Health and partners conducted 30 supplementary immunization activity (SIA) rounds as part of 10 campaign groups, using monovalent OPV type 2 (mOPV2). There were Sabin 2 vaccine strain detections in the environmental (sewage) samples taken after mOPV2 SIAs in each province. Following the initial response, additional cVDPV2 polio cases occurred in other provinces. However, the national surveillance system did not detect any new cVDPV2 polio cases after 9 February 2020. While reporting subpar indicator performance in epidemiological surveillance, the laboratory and environmental data as of May 2021 strongly suggest that Angola successfully interrupted transmission of cVDPV2 early in 2020. Additionally, the COVID-19 pandemic did not allow a formal Outbreak Response Assessment (OBRA). Improving the sensitivity of the surveillance system and the completeness of AFP case investigations will be vital to promptly detect and interrupt viral transmission if a new case or sewage isolate are identified in Angola or central Africa.

Safety, tolerability, and immunogenicity of inactivated poliovirus vaccine with or without E.coli double mutant heat-labile toxin (dmLT) adjuvant in healthy adults; a phase 1 randomized study

BACKGROUND

Inactivated trivalent poliovirus vaccine (IPV) induces humoral immunity, which protects against paralytic poliomyelitis but does not induce sufficient mucosal immunity to block intestinal infection. We assessed the intestinal immunity in healthy adults in Belgium conferred by a co-formulation of IPV with the mucosal adjuvant double mutant Labile Toxin (dmLT) derived from Escherichia coli.

METHODS

Healthy fully IPV-vaccinated 18-45-year-olds were randomly allocated to three groups: on Day 1 two groups received one full dose of IPV (n = 30) or IPV + dmLT (n = 30) in a blinded manner, and the third received an open-label dose of bivalent live oral polio vaccine (bOPV types 1 and 3, n = 20). All groups received a challenge dose of bOPV on Day 29. Participants reported solicited and unsolicited adverse events (AE) using study diaries. Mucosal immune responses were measured by fecal neutralization and IgA on Days 29 and 43, with fecal shedding of challenge viruses measured for 28 days. Humoral responses were measured by serum neutralizing antibody (NAb).

RESULTS

Solicited and unsolicited AEs were mainly mild-to-moderate and transient in all groups, with no meaningful differences in rates between groups. Fecal shedding of challenge viruses in both IPV groups exceeded that of the bOPV group but was not different between IPV and IPV + dmLT groups. High serum NAb responses were observed in both IPV groups, alongside modest levels of fecal neutralization and IgA.

CONCLUSIONS

Addition of dmLT to IPV administered intramuscularly neither affected humoral nor intestinal immunity nor decreased fecal virus shedding following bOPV challenge. The tolerability of the dose of dmLT used in this study may allow higher doses to be investigated for impact on mucosal immunity. Registered on ClinicalTrials.gov - NCT04232943.

Safety and immunogenicity of 3 formulations of a Sabin inactivated poliovirus vaccine produced on the PER.C6® cell line: A phase 2, double-blind, randomized, controlled study in infants vaccinated at 6, 10 and 14 weeks of age

An inactivated poliovirus vaccine candidate using Sabin strains (sIPV) grown on the PER.C6® cell line was assessed in infants after demonstrated immunogenicity and safety in adults. The study recruited 300 infants who were randomized (1:1:1:1) to receive one of 3 dose levels of sIPV or a conventional IPV based on Salk strains (cIPV). Poliovirus-neutralizing antibodies were measured before the first dose and 28 days after the third dose. Reactogenicity was assessed for 7 days and unsolicited adverse events (AEs) for 28 days after each vaccination. Serious AEs (SAEs) were recorded throughout the study. Solicited AEs were mostly mild to moderate. None of the SAEs reported in the study were judged vaccine related, including one fatal SAE due to aspiration of vomitus that occurred 26 days after the third dose of low-dose sIPV. After 3 sIPV vaccinations and across all dose levels, seroconversion (SC) rates were at least 92% against Sabin poliovirus types and at least 80% against Salk types, with a dose-response in neutralizing antibody geometric mean titers (GMTs) observed across the 3 sIPV groups. Compared to cIPV, the 3 sIPV groups displayed similar or higher SC rates and GMTs against the 3 Sabin types but showed a lower response against Salk types 1 and 2; this was most visible for Salk type 1. While the PER.C6® cell line-based sIPV showed an acceptable safety profile and immunogenicity in infants, lower seroprotection against type 1 warrants optimization of dose level and additional clinical evaluation.

Poliomyelitis is a current challenge: long-term sequelae and circulating vaccine-derived poliovirus

For more than 20 years, the World Health Organization Western Pacific Region (WPR) has been polio-free. However, two current challenges are still polio-related. First, around half of poliomyelitis elderly survivors suffer late poliomyelitis sequelae with a substantial impact on daily activities and quality of life, experiencing varying degrees of residual weakness as they age. The post-polio syndrome as well as accelerated aging may be involved. Second, after the worldwide Sabin oral poliovirus (OPV) vaccination, the recent reappearance of strains of vaccine-derived poliovirus (VDPV) circulating in the environment is worrisome and able to persistent person-to-person transmission. Such VDPV strains exhibit atypical genetic characteristics and reversed neurovirulence that can cause paralysis similarly to wild poliovirus, posing a significant obstacle to the elimination of polio. Immunization is essential for preventing paralysis in those who are exposed to the poliovirus. Stress the necessity of maintaining high vaccination rates because declining immunity increases the likelihood of reemergence. If mankind wants to eradicate polio in the near future, measures to raise immunization rates and living conditions in poorer nations are needed, along with strict observation. New oral polio vaccine candidates offer a promissory tool for this goal.

Mucosal COVID-19 vaccines: Risks, benefits and control of the pandemic

Based on mucosal immunization to promote both mucosal and systemic immune responses, next-generation coronavirus disease 2019 (COVID-19) vaccines would be administered intranasally or orally. The goal of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines is to provide adequate immune protection and avoid severe disease and death. Mucosal vaccine candidates for COVID-19 including vector vaccines, recombinant subunit vaccines and live attenuated vaccines are under development. Furthermore, subunit protein vac-cines and virus-vectored vaccines have made substantial progress in preclinical and clinical settings, resulting in SARS-CoV-2 intranasal vaccines based on the previously successfully used nasal vaccines. Additional to their ability to trigger stable, protective immune responses at the sites of pathogenic infection, the development of ‘specific’ mucosal vaccines targeting coronavirus antigens could be an excellent option for preventing future pandemics. However, their efficacy and safety should be confirmed.

Immunity to enteric viruses

Pathogenic enteric viruses are a major cause of morbidity and mortality, particularly among children in developing countries. The host response to enteric viruses occurs primarily within the mucosa, where the intestinal immune system must balance protection against pathogens with tissue protection and tolerance to harmless commensal bacteria and food. Here, we summarize current knowledge in natural immunity to enteric viruses, highlighting specialized features of the intestinal immune system. We further discuss how knowledge of intestinal anti-viral mechanisms can be translated into vaccine development with particular focus on immunization in the oral route. Research reveals that the intestine is a complex interface between enteric viruses and the host where environmental factors influence susceptibility and immunity to infection, while viral infections can have lasting implications for host health. A deeper mechanistic understanding of enteric anti-viral immunity with this broader context can ultimately lead to better vaccines for existing and emerging viruses.

Conducting public health surveillance in areas of armed conflict and restricted population access: a qualitative case study of polio surveillance in conflict-affected areas of Borno State, Nigeria

This study examined the impact of armed conflict on public health surveillance systems, the limitations of traditional surveillance in this context, and innovative strategies to overcome these limitations. A qualitative case study was conducted to examine the factors affecting the functioning of poliovirus surveillance in conflict-affected areas of Borno state, Nigeria using semi-structured interviews of a purposeful sample of participants. The main inhibitors of surveillance were inaccessibility, the destroyed health infrastructure, and the destroyed communication network. These three challenges created a situation in which the traditional polio surveillance system could not function. Three strategies to overcome these challenges were viewed by respondents as the most impactful. First, local community informants were recruited to conduct surveillance for acute flaccid paralysis in children in the inaccessible areas. Second, the informants engaged in local-level negotiation with the insurgency groups to bring children with paralysis to accessible areas for investigation and sample collection. Third, GIS technology was used to track the places reached for surveillance and vaccination and to estimate the size and location of the inaccessible population. A modified monitoring system tracked tailored indicators including the number of places reached for surveillance and the number of acute flaccid paralysis cases detected and investigated, and utilized GIS technology to map the reach of the program. The surveillance strategies used in Borno were successful in increasing surveillance sensitivity in an area of protracted conflict and inaccessibility. This approach and some of the specific strategies may be useful in other areas of armed conflict.

Evaluating stability of attenuated Sabin and two novel type 2 oral poliovirus vaccines in children

Novel oral poliovirus vaccine type 2 (nOPV2) is being developed to reduce the rare occurrence of disease and outbreaks associated with the genetic instability of the Sabin vaccine strains. Children aged 1 to 5 years were enrolled in two related clinical studies to assess safety, immunogenicity, shedding rates and properties of the shed virus following vaccination with nOPV2 (two candidates) versus traditional Sabin OPV type 2 (mOPV2). The anticipated pattern of reversion and increased virulence was observed for shed Sabin-2 virus, as assessed using a mouse model of poliovirus neurovirulence. In contrast, there were significantly reduced odds of mouse paralysis for shed virus for both nOPV2 candidates when compared to shed Sabin-2 virus. Next-generation sequencing of shed viral genomes was consistent with and further supportive of the observed neurovirulence associated with shed Sabin-2 virus, as well as the reduced reversion to virulence of shed candidate viruses. While shed Sabin-2 showed anticipated A481G reversion in the primary attenuation site in domain V in the 5’ untranslated region to be associated with increased mouse paralysis, the stabilized domain V in the candidate viruses did not show polymorphisms consistent with reversion to neurovirulence. The available data from a key target age group for outbreak response confirm the superior genetic and phenotypic stability of shed nOPV2 strains compared to shed Sabin-2 and suggest that nOPV2 should be associated with less paralytic disease and potentially a lower risk of seeding new outbreaks.

Immunochemical and Biophysical Characterization of Inactivated Sabin Poliovirus Products: Insights into Rapid Quality Assessment Tools

The aim of this study was to demonstrate the strength of combining immunochemical and biophysical analysis tools for assessing the quality of Sabin inactivated poliovirus vaccine (Sabin-IPV) bulk products. We assessed Sabin-IPV serotypes 1, 2 and 3 from six different manufacturers and evaluated their comparability through biosensor analysis and biophysical characterization methods, including tryptophan fluorescence and asymmetrical flow field-flow fractionation - multi-angle light scattering analysis. These methods enabled us to assess antigenic as well as conformational and structural integrity profiles, respectively. Based on Sabin-IPV samples that were subjected to accelerated storage conditions, we revealed that existing immunochemical methods exhibit remarkably similar trends to the results obtained by the biophysical characterization methods. While the results underpin that the comparability of Sabin-IPV bulk products of different manufacturers is poor, information about their quality can rapidly be obtained by using both immunochemical and biophysical methods. Furthermore, the study highlights that quality assessment of Sabin-IPV can be obtained through biophysical techniques can complement the assessments performed with monoclonal antibodies and suggests that similar techniques could be employed to characterize other enteroviruses.

Retrospective Analysis of Six Years of Acute Flaccid Paralysis Surveillance and Polio Vaccine Coverage Reported by Italy, Serbia, Bosnia and Herzegovina, Montenegro, Bulgaria, Kosovo, Albania, North Macedonia, Malta, and Greece

Here we analyzed six years of acute flaccid paralysis (AFP) surveillance, from 2015 to 2020, of 10 countries linked to the WHO Regional Reference Laboratory, at the Istituto Superiore di Sanità, Italy. The analysis also comprises the polio vaccine coverage available (2015–2019) and enterovirus (EV) identification and typing data. Centralized Information System for Infectious Diseases and Laboratory Data Management System databases were used to obtain data on AFP indicators and laboratory performance and countries’ vaccine coverage from 2015 to 2019. EV isolation, identification, and typing were performed by each country according to WHO protocols. Overall, a general AFP underreporting was observed. Non-Polio Enterovirus (NPEV) typing showed a high heterogeneity: over the years, several genotypes of coxsackievirus and echovirus have been identified. The polio vaccine coverage, for the data available, differs among countries. This evaluation allows for the collection, for the first time, of data from the countries of the Balkan area regarding AFP surveillance and polio vaccine coverage. The need, for some countries, to enhance the surveillance systems and to promote the polio vaccine uptake, in order to maintain the polio-free status, is evident.

A novel enterovirus in lambs with poliomyelitis and brain stem encephalitis

An Austrian organic dairy sheep farm experienced cases of recumbency and sudden deaths in 3- to 4-week-old lambs. Two animals were subjected to thorough clinical and pathological investigations. Pathohistological analysis identified severe nonsuppurative myelitis and mild nonsuppurative encephalitis. A reverse-transcription quantitative PCR (RT-qPCR) assay for the recently discovered ovine picornavirus causing comparable lesions scored negative. By next-generation sequencing-based metagenomics, a nearly complete genome of a novel enterovirus could be detected and assembled. In situ hybridization using a specifically designed probe revealed robust signals in affected motoneurons of the spinal cord suggesting a causative role of the novel virus.

Indian Academy of Pediatrics (IAP) Advisory Committee on Vaccines and Immunization Practices (ACVIP): Recommended Immunization Schedule (2020-21) and Update on Immunization for Children Aged 0 Through 18 Years

Justification

In view of new developments in vaccinology and the availability of new vaccines, there is a need to revise/review the existing immunization recommendations.

Process

Advisory Committee on Vaccines and Immunization Practices (ACVIP) of Indian Academy of Pediatrics (IAP) had a physical meeting in March, 2020 followed by online meetings (September-October, 2020), to discuss the updates and new recommendations. Opinion of each member was sought on the various recommendations and updates, following which an evidence-based consensus was reached.

Objectives

To review and revise the IAP recommendations for 2020–21 and issue recommendations on existing and new vaccines.

Recommendations

The major changes include recommendation of a booster dose of injectable polio vaccine (IPV) at 4–6 years for children who have received the initial IPV doses as per the ACVIP/IAP schedule, re-emphasis on the importance of IPV in the primary immunization schedule, preferred timing of second dose of varicella vaccine at 3–6 months after the first dose, and uniform dosing recommendation of 0.5 mL (15 µg HA) for inactivated influenza vaccines.

Assessing the impact of polio supplementary immunisation activities on routine immunisation and health systems: a systematic review

Introduction

The Global Polio Eradication Initiative uses polio supplementary immunisation activities (SIAs) as a strategy to increase vaccine coverage and cease poliovirus transmission. Impact of polio SIAs on immunisation systems is frequently debated. We reviewed the impact of polio SIAs on routine immunisation and health systems during the modern era of polio eradication.

Methods

We searched nine databases for studies reporting on polio SIAs and immunisation coverage, financial investment, workforce and health services delivery. We conducted a narrative synthesis of evidence. Records prior to 1994, animal, modelling or case studies data were excluded.

Results

20/1637 unique records were included. Data on vaccine coverage were included in 70% (14/20) studies, workforce in 65% (13/20) and health services delivery in 85% (17/20). SIAs positively contributed to vaccination uptake of non-polio vaccines in seven studies, neutral in three and negative in one. Some polio SIAs contributed to workforce strengthening through training and capacity building. Polio SIAs were accompanied with increased social mobilisation and community awareness building confidence in vaccination programmes. Included studies were programmatic in nature and contained variable data, thus could not be justly critically appraised.

Conclusion

Polio SIAs are successful at increasing polio vaccine coverage, but the resources and infrastructures were not always utilised for delivery of non-polio vaccines and integration into routine service delivery. We found a gap in standardised tools to evaluate SIAs, which can then inform service integration. Our study provides data to inform SIAs evaluations, and provides important considerations for COVID-19 vaccine roll-out to strengthen health systems.

PROSPERO registration number

CRD42020152195.

Isolation and characterization of a Sabin 3/Sabin 1 recombinant vaccine-derived poliovirus from a child with severe combined immunodeficiency

An 8-month-old child diagnosed with severe combined immunodeficiency (SCID) was found to be excreting vaccine-derived poliovirus (VDPVs). Five stool samples from the child and stool samples from 24 contacts were collected during the following 7 months. Complete genome sequence by next generation sequencing (NGS) identified 0.7 to 1.4% nucleotide substitutions in the capsid P1 region of the first and the last isolates compared with Sabin 3 strain. Simplot analysis revealed that all isolates were Sabin 3/Sabin 1 recombinants, sharing a single recombination breakpoint in the 2C region. Multiple nucleotide variants were identified in the 5'UTR (T₄₇₂→C and G₃₉₅→A); amino acid mutations were identified in residues at VP1-6 (Thr to Ile), VP1-105 (Met to Thr), VP1-286 (Arg to Lys), VP2-155 (Lys to Glu), VP3-59 (Ser to Asn) and VP3-91 (Phe to Ser). These variants were commonly observed in other PV strains, which may contribute to attenuation and temperature sensitivity. None of the 24 tested contacts of the patient and related transmits was found to be infected with poliovirus. Our study provides a rapid and reliable method for the characterization of VDPV research in Poliovirus infection. In post-OPV era, immunodeficient people with persistent and chronic infection remain a major challenge for polio eradication in China.

Insight of oral vaccines as an alternative approach to health and disease management: An innovative intuition and challenges

Vaccination is the most suitable and persuasive healthcare program for the prohibition of various deadly diseases. However, the higher production cost and purification strategies are out of reach for the developing nations. In this scenario, development of edible vaccine turns out to be the most promising alternative for remodeling the pharmaceutical industry with reduced production and purification costs. Generally, oral route of vaccination is mostly preferred due to its safety, compliance, low manufacturing cost and most importantly the ability to induce immunity in both systemic and mucosal sites. Genetically modified microorganisms and plants could efficiently be used as vehicles for edible vaccines. Edible vaccines are supposed to reduce the risk associated with traditional vaccines. Currently, oral vaccines are available in the market for several viral and bacterial diseases like cholera, hepatitis B, malaria, rabies etc. Herein, the review focuses on the breakthrough events in the area of edible vaccines associated with dietary microbes and plants for better control over diseases.

Magnitude and causes of routine immunization disruptions during COVID-19 pandemic in developing countries

The ongoing pandemic of COVID-19 is a threat to various routine healthcare services. India's routine immunization (RI) campaign is one of largest ever known. In this review, we discuss the magnitude of disruption of RI activities due to COVID-19 pandemic, various causes of it and recommend ways to reduce the disruptions. Prominent literature databases were searched till April 30, 2021 for articles reporting disruptions of RI due to COVID-19. One study from India and numerous from outside India reported significant declines in the vaccine coverage rates during the lockdown period, which ranged from March 2020 till August 2020 in different regions of the world. Some reported disruptions for all vaccines, while a few reported sparing of birth doses. Shortage of healthcare workers due for them being diverted to patient care services and their reduced movement due to lockdowns and non-availability of public transport were prominent causes. Parents avoided RI sessions as they feared them or their children getting infected. They also faced travel restrictions, just like the healthcare workers. Children of school entry age and those from poorer socio-demographic profile appeared to miss the doses more frequently. Ministry of Health and Family Welfare, India has issued guidelines for conducting fixed and outreach RI sessions while following COVID-appropriate behavior. Promptly identifying missed out children and scheduling catch-up sessions is required to sustain the gains made over the decades by the immunization program of India.

The immediate impact of the COVID-19 pandemic on polio immunization and surveillance activities

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.

Neurologic Safety Monitoring of COVID-19 Vaccines: Lessons From the Past to Inform the Present

The spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has triggered a global effort to rapidly develop and deploy effective and safe coronavirus disease 2019 (COVID-19) vaccinations. Vaccination has been one of the most effective medical interventions in human history, although potential safety risks of novel vaccines must be monitored, identified, and quantified. Adverse events must be carefully assessed to define whether they are causally associated with vaccination or coincidence. Neurologic adverse events following immunizations are overall rare but with significant morbidity and mortality when they occur. Here, we review neurologic conditions seen in the context of prior vaccinations and the current data to date on select COVID-19 vaccines including mRNA vaccines and the adenovirus-vector COVID-19 vaccines, ChAdOx1 nCOV-19 (AstraZeneca) and Ad26.COV2.S Johnson & Johnson (Janssen/J&J).

Progress Toward Poliomyelitis Eradication - Pakistan, January 2020-July 2021

When the Global Polio Eradication Initiative began in 1988, wild poliovirus (WPV) transmission was occurring in 125 countries; currently, only WPV type 1 (WPV1) transmission continues, and as of August 2021, WPV1 transmission persists in only two countries (1,2). This report describes Pakistan's progress toward polio eradication during January 2020-July 2021 and updates previous reports (3,4). In 2020, Pakistan reported 84 WPV1 cases, a 43% reduction from 2019; as of August 25, 2021, Pakistan has reported one WPV1 case in 2021. Circulating vaccine-derived poliovirus (cVDPV) emerges as a result of attenuated oral poliovirus vaccine (OPV) virus regaining neurovirulence after prolonged circulation in underimmunized populations and can lead to paralysis. In 2019, 22 cases of cVDPV type 2 (cVDPV2) were reported in Pakistan, 135 cases were reported in 2020, and eight cases have been reported as of August 25, 2021. Because of the COVID-19 pandemic, planned supplementary immunization activities (SIAs)* were suspended during mid-March-June 2020 (3,5). Seven SIAs were implemented during July 2020-July 2021 without substantial decreases in SIA quality. Improving the quality of polio SIAs, vaccinating immigrants from Afghanistan, and implementing changes to enhance program accountability and performance would help the Pakistan polio program achieve its goal of interrupting WPV1 transmission by the end of 2022.

Wastewater-Based Epidemiology and Long-Read Sequencing to Identify Enterovirus Circulation in Three Municipalities in Maricopa County, Arizona, Southwest United States between June and October 2020

We used wastewater-based epidemiology and amplicon-based long-read high-throughput sequencing for surveillance of enteroviruses (EVs) in Maricopa County, Arizona, Southwest United States. We collected 48 samples from 13 sites in three municipalities between 18 June and 1 October 2020, and filtered (175 mL each; 0.45 µm pore size) and extracted RNA from the filter-trapped solids. The RNA was converted to cDNA and processed through two workflows (Sanger sequencing (SSW) and long-read Illumina sequencing (LRISW)) each including a nested polymerase chain reaction (nPCR) assay. We subjected the ~350 bp amplicon from SSW to Sanger sequencing and the ~1900-2400 bp amplicon from LRISW to Illumina sequencing. We identified EV contigs from 11 of the 13 sites and 41.67% (20/48) of screened samples. Using the LRISW, we detected nine EV genotypes from three species (Enterovirus A (CVA4, EV-A76, EV-A90), Enterovirus B (E14) and Enterovirus C (CVA1, CVA11, CVA13, CVA19 and CVA24)) with Enterovirus C representing approximately 90% of the variants. However, the SSW only detected the five Enterovirus C types. Similarity and phylogenetic analysis showed that multiple Enterovirus C lineages were circulating, co-infecting and recombining in the population during the season despite the SARS-CoV-2 pandemic and the non-pharmaceutical public health measures taken to curb transmission.

In vitro antiviral activity of peptide-rich extracts from seven Nigerian plants against three non-polio enterovirus species C serotypes

Background

As frequent viral outbreaks continue to pose threat to public health, the unavailability of antiviral drugs and challenges associated with vaccine development underscore the need for antiviral drugs discovery in emergent moments (endemic or pandemic). Plants in response to microbial and pest attacks are able to produce defence molecules such as antimicrobial peptides as components of their innate immunity, which can be explored for viral therapeutics.

Methods

In this study, partially purified peptide-rich fraction (P-PPf) were obtained from aqueous extracts of seven plants by reverse-phase solid-phase extraction and cysteine-rich peptides detected by a modified TLC method. The peptide-enriched fractions and the aqueous (crude polar) were screened for antiviral effect against three non-polio enterovirus species C members using cytopathic effect reduction assay.

Results

In this study, peptide fraction obtained from Euphorbia hirta leaf showed most potent antiviral effect against Coxsackievirus A13, Coxsackievirus A20, and Enterovirus C99 (EV-C99) with IC₅₀ < 2.0 µg/mL and selective index ≥ 81. EV-C99 was susceptible to all partially purified peptide fractions except Allamanda blanchetii leaf.

Conclusion

These findings establish the antiviral potentials of plants antimicrobial peptides and provides evidence for the anti-infective use of E. hirta in ethnomedicine. This study provides basis for further scientific investigation geared towards the isolation, characterization and mechanistic pharmacological study of the detected cysteine-rich peptides.

The importance of enterovirus surveillance in a post-polio world

Poliovirus is known to most people in the world as the cause of polio, a devastating paralytic disease from the past. Success in polio eradication has understandably translated into stricter containment plans for poliovirus, coordinated by WHO. In this Personal View, we discuss the impact of recent biosafety level 3+ guidelines for handling potential poliovirus-containing diagnostic specimens, which has resulted in closure of many national WHO poliovirus reference laboratories. This reduction in laboratory capacity has a knock-on effect of capability to detect and characterise non-polio enteroviruses in samples obtained from patients with neurological symptoms. The development is of concern given the widespread circulation of non-polio enteroviruses, their role as the most common cause of meningitis worldwide, and their involvement in other severe neurological conditions, such as acute flaccid myelitis and encephalitis. These disease presentations have increased substantially in the past decade, and have been associated with major outbreaks of enterovirus D68 and enterovirus A71, leaving many who survived with lasting paralysis and disabilities. To address this growing gap in diagnostic and surveillance capability, we have established the European Non-Poliovirus Enterovirus Network (also known as ENPEN) as a supra-national, non-commercial, core reference consortium. Our consortium will develop, test, and implement generic surveillance platforms for non-polio enteroviruses and other emerging viral diseases.

Using immunisation caregiver journey interviews to understand and optimise vaccination uptake: lessons from Sierra Leone

Quantitative and qualitative assessments have revealed diverse factors that influence the uptake of childhood immunisation services and shed light on reasons for vaccination delays and refusals. UNICEF and partner organisations developed the Immunisation Caregiver Journey Framework as a novel way to understand caregiver experiences in accessing and receiving immunisation services for children. This framework aims to help immunisation programmes identify vaccination barriers and opportunities to improve vaccination uptake by enhancing the overall caregiver journey in a systems-focused manner, using human-centred design principles. In this paper, we adapt the framework into a flexible qualitative inquiry approach with theoretical guidance from interpretative phenomenology. We draw from the implementation experiences in Sierra Leone to inform methodological guidance on how to design and implement the Immunisation Caregiver Journey Interviews (ICJI) to understand the lived experiences of caregivers as they navigate immunisation services for their children. Practical guidance is provided on sampling techniques, conducting interviews, data management, data analysis and the use of data to inform programmatic actions. When properly implemented, the ICJI approach generates a rich qualitative understanding of how caregivers navigate household and community dynamics, as well as primary healthcare delivery systems. We argue that understanding and improving the caregiver journey will enhance essential immunisation outcomes, such as the completion of the recommended vaccination schedule, timeliness of vaccination visits and reduction in dropouts between vaccine doses.

Development of a Quantitative One-Step RT-PCR Method for the Detection of Sabin 2 Virus Contamination in a Novel Oral Poliovirus Vaccine Type 2

To control circulating vaccine-derived type 2 poliovirus outbreaks, a more genetically stable novel Oral Poliovirus Vaccine type 2 (nOPV2) was developed by targeted modifications of Sabin 2 genome. Since the use of OPV2 made of Sabin 2 strain has been stopped, it is important to exclude the possibility that batches of nOPV2 are contaminated with Sabin 2 virus. Here, we report the development of a simple quantitative one-step reverse-transcription polymerase chain reaction assay for the detection and quantitation of Sabin 2 virus in the presence of overwhelming amounts of nOPV2 strain. The method is specific and linear within 8 log₁₀ range even in the presence of relevant amounts of nOPV2 virus. It is sensitive, with a lower limit of detection of 0.2 CCID₅₀/mL (an equivalent of 198 genome copies per mL), and generates reproducible results. This assay can be used for quality control and lot release of the nOPV2.

Challenging definitions and diagnostic approaches for ancient rare diseases: The case of poliomyelitis

OBJECTIVE

This paper aims to contribute to the definition of ancient rare diseases in skeletons displaying pathologies associated with paralysis. It uses a new suite of methods, which can be applied to challenging cases of possible paralysis in archaeologically-derived human skeletal material, specifically applied to the identification of poliomyelitis.

MATERIALS

An adult male skeleton from Roman Halbturn, Austria.

METHODS

Morphological and entheseal change analyses, CT scans, X-rays, cross-section morphology, and histology, alongside modern clinical, as well as historic, literature were used to discuss paralyses.

RESULTS

The results suggest a diagnosis of poliomyelitis; now considered a rare disease, but perhaps ubiquitous in antiquity, thus complicating the definition of 'rare disease'.

CONCLUSIONS

The integrated methodological procedures employed for this case constitutes a replicable and thorough approach to diagnosis, and explores the nature of ancient rare diseases. Due to the socio-environmental aspects of poliomyelitis transmission, it is likely that polio was likely not rare in the past. Therefore, the definition of 'rare diseases in the past' must include rarely occurring rarely diagnosed diseases due to biases and challenges within the archaeological and environmental record.

SIGNIFICANCE

The developed suite of methods has not been applied to establish a diagnosis of polio in the past.

LIMITATIONS

The individual considered in this study is fairly well-preserved; thus, this set of analyses may not be applicable to all remains where preservation is poor or highly fragmentary, and the discussion of rare diseases requires relatively secure diagnoses and context.

SUGGESTIONS FOR FURTHER RESEARCH

Large collections and series of skeletal human remains are recommended to develop definitive conclusions.

Stopping a polio outbreak in the midst of war: Lessons from Syria

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 < 3 doses of oral poliovirus vaccine (OPV). After adjusting for age and sex, non-polio AFP case-patients aged 6-59 months in outbreak-affected areas had 2.5 (95% CI: 1.1-5.7) increased odds of being unvaccinated with OPV compared with non-polio AFP case-patients in the same age group in other parts of Syria. Three outbreak response rounds of monovalent OPV type 2 (mOPV2) vaccination were conducted, with governorate-level coverage mostly exceeding 80%.

INTERPRETATION

Significant declines in both national and subnational polio vaccination coverage, precipitated by war and a humanitarian crisis, led to a cVDPV2 outbreak in Syria that was successfully contained following three rounds of mOPV2 vaccination.

Total hip replacement in patient with residual poliomyelitis with neglected femoral neck fracture

A 71-year-old man with residual poliomyelitis was referred to the orthopaedic surgeons with a neglected left femoral neck fracture of the paralytic limb. He had presented at another hospital with left groin pain and inability to weight bear 4 weeks earlier after a fall from standing height, but had delayed treatment due to his insistence on waiting until he returned to his home country.Successful treatment of residual poliomyelitis fractures requires early union as well as early mobilisation and rehabilitation. This patient presented to the orthopaedic surgeons with a challenging case due to the delay in treatment and the fact that the fracture was basicervical which results in an unstable fracture. Surgical expertise was required to decide on the optimum surgical option and a total hip arthroplasty was performed. The patient made a good recovery following physiotherapy as evidenced clinically and radiologically.

Neuromuscular Scoliosis: When, Who, Why and Outcomes

Scoliosis has a very high prevalence among patients with neuromuscular disease involving the thoracic spine and truncal muscles. Physical examination and radiographs are used to screen for presence of scoliosis and monitor progression. Management includes therapy participation, optimizing equipment and orthotic use, and possible surgical intervention. Unlike idiopathic adolescent scoliosis, curves tend to progress despite orthotic use compliance. Associated pelvic obliquity creates risk for pressure sores and pain. As such, education of caregivers is a key point of optimizing management.

The Current State: Epidemiology and Working Toward Eradication

Acute polio, once epidemic and a significant source of paralysis and disability, has been dramatically reduced through global vaccination programs. Although vaccination efforts have experienced a setback because of COVID-19, resulting in increased number of vaccine-associated and wild virus infections, polio eradication is still a realistic goal that will result in significant cost savings. The secondary health issues related to aging with the residual effects of polio, including postpolio syndrome, will persist for many years posteradication. Continued education of medical professionals is essential to ensure provision of the necessary care to this population.

High Diversity of Human Non-Polio Enterovirus Serotypes Identified in Contaminated Water in Nigeria

Human enteroviruses (EVs) are highly prevalent in sewage and have been associated with human diseases with complications leading to severe neurological syndromes. We have used a recently developed molecular method to investigate the presence of EVs in eight samples collected in 2017–2018 from water streams contaminated by drainage channels in three different locations in Nigeria. A total of 93 human EV strains belonging to 45 different serotypes were identified, far exceeding the number of strains and serotypes found in similar samples in previous studies. Next generation sequencing analysis retrieved whole-capsid genomic nucleotide sequences of EV strains belonging to all four A, B, C, and D species. Our results further demonstrate the value of environmental surveillance for the detection of EV transmission of both serotypes commonly associated with clinical syndromes, such as EV-A71, and those that appear to circulate silently but could eventually cause outbreaks and disease. Several uncommon serotypes, rarely reported elsewhere, were detected such as EV-A119, EV-B87, EV-C116, and EV-D111. Ten EV serotypes were detected in Nigeria for the first time and two of them, CV-A12 and EV-B86, firstly described in Africa. This method can be expanded to generate whole-genome EV sequences as we show here for one EV-D111 strain. Our data revealed phylogenetic relationships of Nigerian sewage strains with EV strains reported elsewhere, mostly from African origin, and provided new insights into the whole-genome structure of emerging serotype EV-D111 and recombination events among EV-D serotypes.

COVID-19 in comparison with other emerging viral diseases: risk of geographic spread via travel

Purpose of review

The COVID-19 pandemic poses a major global health threat. The rapid spread was facilitated by air travel although rigorous travel bans and lockdowns were able to slow down the spread. How does COVID-19 compare with other emerging viral diseases of the past two decades?

Recent findings

Viral outbreaks differ in many ways, such as the individuals most at risk e.g. pregnant women for Zika and the elderly for COVID-19, their vectors of transmission, their fatality rate, and their transmissibility often measured as basic reproduction number. The risk of geographic spread via air travel differs significantly between emerging infectious diseases.

Summary

COVID-19 is not associated with the highest case fatality rate compared with other emerging viral diseases such as SARS and Ebola, but the combination of a high reproduction number, superspreading events and a globally immunologically naïve population has led to the highest global number of deaths in the past 20 decade compared to any other pandemic.

The Impact of the COVID-19 Pandemic on Immunization Campaigns and Programs: A Systematic Review

The COVID-19 pandemic has had an impact on health service delivery, including immunization programs, and this review assesses the impact on vaccine coverage across the globe and identifies the potential underlying factors. A systematic search strategy was employed on PubMed, Embase, MedRxiv, BioRxiv, and WHO COVID-19 databases from December 2019 till 15 September 2020. Two review authors independently assessed studies for inclusion, assessed quality, and extracted the data (PROSPERO registration #CRD42020182363). A total of 17 observational studies were included. The findings suggest that there was a reduction in the vaccination coverage and decline in total number of vaccines administered, which led to children missing out on their vaccine doses. An approximately fourfold increase was also observed in polio cases in polio endemic countries. Factors contributing to low vaccine coverage included fear of being exposed to the virus at health care facilities, restriction on city-wide movements, shortage of workers, and diversion of resources from child health to address the pandemic. As the world re-strategizes for the post-2020 era, we should not let a crisis go to waste as they provide an opportunity to establish guidelines and allocate resources for future instances. High-quality supplementary immunization activities and catch-up programs need to be established to address gaps during the pandemic era.

Mutation, Selection, and Bottlenecks in Polio Vaccine Reversion

Troubled by an unstable world beset by new and emerging viruses? Virus evolution is here to help. Through detailed studies of poliovirus vaccine reversion to virulence, Valesano and colleagues remind us that some things in life can, indeed, be counted on.

Indian Academy of Pediatrics (IAP) Advisory Committee on Vaccines and Immunization Practices (ACVIP): Recommended Immunization Schedule (2020-21) and Update on Immunization for Children Aged 0 Through 18 Years

JUSTIFICATION

In view of new developments in vaccinology and the availability of new vaccines, there is a need to revise/review the existing immunization recommendations.

PROCESS

Advisory Committee on Vaccines and Immunization Practices (ACVIP) of Indian Academy of Pediatrics (IAP) had a physical meeting in March, 2020 followed by online meetings (September-October, 2020), to discuss the updates and new recommendations. Opinion of each member was sought on the various recommendations and updates, following which an evidence-based consensus was reached.

OBJECTIVES

To review and revise the IAP recommendations for 2020-21 and issue recommendations on existing and new vaccines.

RECOMMENDATIONS

The major changes include recommendation of a booster dose of injectable polio vaccine (IPV) at 4-6 years for children who have received the initial IPV doses as per the ACVIP/IAP schedule, re-emphasis on the importance of IPV in the primary immunization schedule, preferred timing of second dose of varicella vaccine at 3-6 months after the first dose, and uniform dosing recommendation of 0.5 mL (15 µg HA) for inactivated influenza vaccines.

Impact of COVID-19 on polio vaccination in Pakistan: a concise overview

The pandemic of coronavirus disease 2019 (COVID-19) has disrupted immunization programs around the globe, potentially increasing life-threatening vaccine-preventable diseases. Pakistan and Afghanistan are the only countries, which are still struggling to eradicate wild poliovirus. All vaccination campaigns in Pakistan were suspended in April due to the COVID-19 outbreak, leading 40 million children to miss out on polio vaccination. Like the climate crisis, the COVID-19 pandemic could be regarded as a child-rights crisis because it could have life-threatening impact over children, who need immunization, now and in the long-term. Delays in polio vaccination programs might not have immediate impact but, in the long-term, the increase in polio cases in Pakistan could result in the global export of infections. Therefore, healthcare authorities must intensify their efforts to track and vaccinate unvaccinated children in countries like Pakistan and Afghanistan. Polio vaccination campaigns need to resume immediately, so we suggest applying social distancing measures along with standard operating procedure to flatten the transmission curve of COVID-19. Furthermore, the concurrent emergence of cVDPV2 means that tOPV should temporarily be used for primary immunization. In the current review, we have discussed delays in polio vaccination, surveillance of polio viruses, reported cases in Pakistan along with recommendations to overcome interrupted immunization.

'Most at risk' for COVID19? The imperative to expand the definition from biological to social factors for equity

First recognized in December 2019, the Coronavirus Disease 2019 (COVID19) was declared a global pandemic by the World Health Organization on March 11, 2020. To date, the most utilized definition of 'most at risk' for COVID19 morbidity and mortality has focused on biological susceptibility to the virus. This paper argues that this dominant biomedical definition has neglected the 'fundamental social causes' of disease, constraining the effectiveness of prevention and mitigation measures; and exacerbating COVID19 morbidity and mortality for population groups living in marginalizing circumstances. It is clear - even at this early stage of the pandemic - that inequitable social conditions lead to both more infections and worse outcomes. Expanding the definition of 'most at risk' to include social factors is critical to implementing equitable interventions and saving lives. Prioritizing populations with social conditions is necessary for more effective control of the epidemic in its next phase; and should become standard in the planning for, and prevention and mitigation of all health conditions. Reversing disparities and health inequities is only possible through an expansion of our 'most-at-risk' definition to also include social factors.

Viruses That Can and Cannot Coexist With Humans and the Future of SARS-CoV-2

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a worldwide pandemic. Many projections concerning the outbreak, such as the estimated number of cases and deaths in upcoming months, have been made available. However, what happens to the virus after the pandemic subsides has not been fully explored. In this article, we discuss the ways that past and present human viruses have emerged via zoonotic transmission, the mechanisms that they have acquired the ability for effective transmission among humans, the process to sustain a chain of transmission to coexist with humans, and the factors important for complete containment leading to eradication of viruses. These aspects of viral disease may provide clues for the future path that SARS-CoV-2 might take in relation to human infection.