Progress Toward Poliovirus Containment Implementation - Worldwide, 2019-2020

Beyond polio: Exploring non-polio enteroviruses, global health preparedness, and the "Disease X" paradigm

Background and Aims

Disease X represents the possibility that an unidentified infection may spread globally and start a pandemic. This study explored various aspects of emerging non-polio enteroviruses (NPEVs) as a possible source of "Disease X," an enigmatic agent declared by the World Health Organization, and discussed the potential impact of NPEVs on global public health.

Methods

In this perspective article, we collected information from publicly available sources such as Google Scholar, PubMed, and Scopus. We used NPEVs, viral diseases, pandemics, and zoonotic diseases as keywords. We extracted information from the most relevant articles.

Results

Notable outbreaks caused by NPEVs include enterovirus D68 (EV-D68) and enterovirus A71 (EV-A71), among many others. With a focus on therapeutic and preventative components, alternate modes of therapy, and the development of broad-spectrum antivirals, this analysis looks at the origin, epidemiology, genetic alterations, transmission dynamics, and disease pathophysiology of NPEVs. The information presented in the review indicates the current risk assessment of NPEVs, taking into account the following factors: the need for research and therapeutic interventions, the diversity of clinical manifestations, the impact of genetic variability on virulence, the persistence of emergence despite vaccination efforts, recurrent outbreaks, and the global impact of these viruses.

Conclusion

There is a possibility that NPEVs could trigger global pandemics based on their zoonotic origins and urges for complete readiness, continuous research, cooperation, and a comprehensive strategy to combat emerging infectious diseases in a constantly changing global environment. It is peak time to acknowledge how important it is to abide by safety and health laws to prevent these illnesses.

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.

Establishment of a Poliovirus Containment Program and Containment Certification Process for Poliovirus-Essential Facilities, United States 2017-2022

Upon declaration of poliovirus (PV) type 2 eradication in 2015, the World Health Organization (WHO) published PV containment requirements in the Global Action Plan III (GAPIII) for mitigating the risk of a facility-associated release post eradication. In 2018, the 71st World Health Assembly resolution urged member states retaining PV to appoint a National Authority for Containment (NAC), reduce the number of PV facilities, and submit applications for containment certification. The United States (US) NAC was established in 2018 for containment oversight, and two paths to WHO GAPIII containment certification were developed. Facilities retaining PV were identified through national poliovirus containment surveys. The US NAC conducted 27 site visits at 18 facilities (20 laboratories: A/BSL-2 (65%), A/BSL-3 (20%), and storage-only (15%)) to verify the implementation of US NAC's preliminary containment measures. The NAC identified areas for improvement in seven categories: primary containment, decontamination, hand hygiene, security, emergency response, training, and immunization practices. Sixteen facility applications were endorsed to pursue poliovirus-essential facility (PEF) certification, whereas four facilities opted to withdraw during the containment certification process. The US made noteworthy progress in PV containment to enhance biosafety and biosecurity practices at US PV facilities to safeguard the polio eradication effort.

Understanding Factors Contributing to Vaccine Hesitancy in a Large Metropolitan Area

Vaccine hesitancy has become a major global concern, leading to a significant decrease in the vaccination rate, with the World Health Organization recognizing it as one of the top ten threats to public health. Moreover, the health cost generated is evaluated to be 27 billion dollars per year in the US alone. To investigate the association between demographic variables and knowledge, attitudes, and behaviours related to vaccination, a survey-based cross-sectional study was conducted with 1163 individuals. Three models were used to perform a multiple linear regression analysis. In Model I, knowledge about vaccinations was found to be associated with smoking habits, education, and marital status. In Model II, attitudes towards vaccinations were significantly associated with sex, smoking habits, education, marital status, and knowledge. In Model III, behaviours related to vaccination were associated with sex, smoking habits, having children, knowledge, and attitudes. One potential solution to improve behaviours related to vaccinations in the general population is to implement specific public health programs, which can be a cost-effective intervention. This study provides valuable insights into the determinants of knowledge, attitudes, and behaviours related to vaccinations in the general population.

Genetic characterization and molecular evolution of type 3 vaccine-derived polioviruses from an immunodeficient patient in China

In 2013, a case of immunodeficiency vaccine-derived poliovirus (iVDPV) was identified in Jiangxi Province, China. In this study, we purified 14 type 3 original viral isolates from this case and characterized the molecular evolution of these iVDPVs for 298 days. Genetic variants were found in most of the original viral isolates, with complex genetic and evolutionary relationships among the variants. A phylogenetic tree constructed based on the P1 region showed that these iVDPVs were classified into lineage A and B. The dominant lineage B represents a major trend in virus evolution. The nucleotide substitution rate at the third codon position (3CP) estimated by the BEAST program was 1.76 × 10-2 substitutions/site/year (95% HPD: 1.23-2.39 × 10-2). The initial OPV dose was given dating back to March 2013, which was close to the time of the last OPV vaccination, suggesting that OPV infection may have originated with the last dose of vaccine. Recombinant analysis showed that these iVDPVs were inter-vaccine recombinants with two recombination patterns, S3/S2/S1 and S3/S2/S3/S2/S1. Whole genome sequence analysis revealed that key nucleotide sites (C472U, C2034U, U2493C) associated with the attenuated phenotype of Sabin 3 have been replaced. Temperature sensitivity test showed that all tested strains were temperature-sensitive, except for the variant Day11-5. Interestingly, we observed that the variant Day11-5 temperature resistance properties may be associated with the Lys to Met substitution at the VP2-162 site. Serological test and whole genome sequence analysis showed that the seropositivity rate remained high, and mutations in the antigenic sites did not significantly alter neutralization ability.

Descriptive epidemiology of poliomyelitis cases due to wild poliovirus type 1 and wild poliovirus type 3 in Nigeria, 2000-2020

Introduction

in August 2020, the World Health Organization African Region was certified free of wild poliovirus (WPV) when Nigeria became the last African country to interrupt wild poliovirus transmission. The National Polio Emergency Operations Center instituted in 2012 to coordinate and manage Nigerian polio eradication efforts reviewed the epidemiology of WPV cases during 2000-2020 to document lessons learned.

Methods

we analyzed reported WPV cases by serotype based on age, oral poliovirus vaccine immunization history, month and year of reported cases, and annual geographic distribution based on incidence rates at the Local Government Area level. The observed trends of cases were related to major events and the poliovirus vaccines used during mass vaccination campaigns within the analysis period.

Results

a total of 3,579 WPV type 1 and 1,548 WPV type 3 laboratory-confirmed cases were reported with onset during 2000-2020. The highest WPV incidence rates per 100,000 population in Local Government Areas were 19.4, 12.0, and 11.3, all in 2006. Wild poliovirus cases were reported each year during 2000-2014; the endemic transmission went undetected throughout 2015 until the last cases in 2016. Ten events/milestones were highlighted, including insurgency in the northeast which led to a setback in 2016 with four cases from children previously trapped in security-compromised areas.

Conclusion

Nigeria interrupted WPV transmission despite the challenges faced because of the emergency management approach, implementation of mass vaccination campaigns, the commitment of the government agencies, support from global polio partners, and special strategies deployed to conduct vaccination and surveillance in the security-compromised areas.

Assessment of Enterovirus Excretion and Identification of VDPVs in Patients with Primary Immunodeficiency in India: Outcome of ICMR-WHO Collaborative Study Phase-I

The emergence of vaccine-derived polioviruses (VDPVs) in patients with Primary Immunodeficiency (PID) is a threat to the polio-eradication program. In a first of its kind pilot study for successful screening and identification of VDPV excretion among patients with PID in India, enteroviruses were assessed in stool specimens of 154 PID patients across India in a period of two years. A total of 21.42% of patients were tested positive for enteroviruses, 2.59% tested positive for polioviruses (PV), whereas 18.83% of patients were positive for non-polio enteroviruses (NPEV). A male child of 3 years and 6 months of age diagnosed with Hyper IgM syndrome was detected positive for type1 VDPV (iVDPV1) with 1.6% nucleotide divergence from the parent Sabin strain. E21 (19.4%), E14 (9%), E11 (9%), E16 (7.5%), and CVA2 (7.5%) were the five most frequently observed NPEV types in PID patients. Patients with combined immunodeficiency were at a higher risk for enterovirus infection as compared to antibody deficiency. The high susceptibility of PID patients to enterovirus infection emphasizes the need for enhanced surveillance of these patients until the use of OPV is stopped. The expansion of PID surveillance and integration with a national program will facilitate early detection and follow-up of iVDPV excretion to mitigate the risk for iVDPV spread.

Enterovirus A71 antivirals: Past, present, and future

Enterovirus A71 (EV-A71) is a significant human pathogen, especially in children. EV-A71 infection is one of the leading causes of hand, foot, and mouth diseases (HFMD), and can lead to neurological complications such as acute flaccid myelitis (AFM) in severe cases. Although three EV-A71 vaccines are available in China, they are not broadly protective and have reduced efficacy against emerging strains. There is currently no approved antiviral for EV-A71. Significant progress has been made in developing antivirals against EV-A71 by targeting both viral proteins and host factors. However, viral capsid inhibitors and protease inhibitors failed in clinical trials of human rhinovirus infection due to limited efficacy or side effects. This review discusses major discoveries in EV-A71 antiviral development, analyzes the advantages and limitations of each drug target, and highlights the knowledge gaps that need to be addressed to advance the field forward.

Current understandings of the impact of mandatory vaccination laws in Europe

Vaccinations are among the most successful preventive tools to protect collective health. In response to alarming vaccines preventable diseases (VPDs) outbreaks resurgence, decreased vaccination coverage and vaccine refusal, several European countries have recently revised their vaccination policies introducing or extending mandatory vaccinations. This review examines the health, political and ethical aspects of mandatory vaccination.The authors first clarify terms and definitions and propose a conceptual framework of mandatory policies. Second, they describe the current status of mandatory childhood immunization programmes in Europe, assessing selected mandatory laws. Third, as the authors conduct a systematic review of the literature (retrieving from Medline 17 relevant records between 2010 and 2020), they take an analytical approach to measure the impact of mandatory vaccination policies on both VPDs control and immunization coverage, but also on population attitudes toward vaccines. 40% of European countries currently have mandatory vaccination policies; however, policies vary widely and, although there is evidence of increased vaccine uptake, their impact on informed adherence to preventive behaviors is scant.Although mandatory vaccination policies might be needed to protect collective health in times of emergency, public health goals of VPD prevention and health promotion should primarily be pursued through health education and population empowerment.