Public health response to the silent reintroduction of wild poliovirus to Israel, 2013-2014

Genetic Variants and Protective Immunity against SARS-CoV-2

The novel coronavirus-19 (SARS-CoV-2), has infected numerous individuals worldwide, resulting in millions of fatalities. The pandemic spread with high mortality rates in multiple waves, leaving others with moderate to severe symptoms. Co-morbidity variables, including hypertension, diabetes, and immunosuppression, have exacerbated the severity of COVID-19. In addition, numerous efforts have been made to comprehend the pathogenic and host variables that contribute to COVID-19 susceptibility and pathogenesis. One of these endeavours is understanding the host genetic factors predisposing an individual to COVID-19. Genome-Wide Association Studies (GWAS) have demonstrated the host predisposition factors in different populations. These factors are involved in the appropriate immune response, their imbalance influences susceptibility or resistance to viral infection. This review investigated the host genetic components implicated at the various stages of viral pathogenesis, including viral entry, pathophysiological alterations, and immunological responses. In addition, the recent and most updated genetic variations associated with multiple host factors affecting COVID-19 pathogenesis are described in the study.

Optimal allocation and operation of sewer monitoring sites for wastewater-based disease surveillance: A methodological proposal

Wastewater-based epidemiology (WBE) is drawing increasing attention as a promising tool for an early warning of emerging infectious diseases such as COVID-19. This study demonstrated the utility of a spatial bisection method (SBM) and a global optimization algorithm (i.e., genetic algorithm, GA), to support better designing and operating a WBE program for disease surveillance and source identification. The performances of SBM and GA were compared in determining the optimal locations of sewer monitoring manholes to minimize the difference among the effective spatial monitoring scales of the selected manholes. While GA was more flexible in determining the spatial resolution of the monitoring areas, SBM allows stepwise selection of optimal sampling manholes with equiareal subcatchments and lowers computational cost. Upon detecting disease outbreaks at a regular sewer monitoring site, additional manholes within the catchment can be selected and monitored to identify source areas with a required spatial resolution. SBM offered an efficient method for rapidly searching for the optimal locations of additional sampling manholes to identify the source areas. This study provides strategic and technical elements of WBE including sampling site selection with required spatial resolution and a source identification method.

Relationship Between Helicobacter pylori IgG Seroprevalence and the Immune Response to Poliovirus Vaccine Among School-Age Children From a Population With Near-Universal Immunity Level

Objectives

To examine the association between Helicobacter pylori seroprevalence and serum pepsinogens (PGs) as markers of gastric inflammation), with high neutralizing antibody titers to poliovirus type 1 and 3 vaccine strains among children age 3–4 years, subsequent to sub-clinical infection acquired during a wild-type poliovirus type 1 outbreak in Israel.

Methods

A serosurvey was conducted among 336 children aged 5–17 years who were vaccinated with both inactivated polio vaccine and oral polio vaccines. H. pylori serum IgG antibodies and PG concentrations were measured using ELISA. Neutralizing antibodies to poliovirus vaccine strains were measured and children with a titer ≥1:8 were considered immune. High-level immunity was defined as having a serum NA titer >1:2048. Propensity score inverse weighting was used to account for confounders.

Results

Neutralizing antibodies titers ≥1:8 to poliovirus type 1 and 3 vaccine strains were found in 99.4 and 98.2% of the children, respectively. An inverse association was found between H. pylori seropositivity accompanied by PGI:PGII ratio ≤6.5 (marker of gastric inflammation) and high-level immunity to poliovirus type 1: OR 0.39 (95% CI 0.68–0.91), p = 0.027. The association between H. pylori seropositivity of CagA virulent phenotype and polio high immunity was not significant. The association between H. pylori seropositivity and high neutralizing antibodies to type 3 poliovirus was of low magnitude and not significant.

Conclusions

H. pylori seroprevalence accompanied by evidence of gastric inflammation was inversely correlated with high titers of neutralizing antibodies to poliovirus in children from a population with near universal polio immunity.

The National Immunization Technical Advisory Group in Israel

National Immunization Technical Advisory Groups (NITAGs) are defined by the World Health Organization as multidisciplinary groups of health experts who are involved in the development of a national immunization policy. The NITAG has the responsibility to provide independent, evidence-informed advice to the policy makers and national programme managers, on policy issues and questions related to immunization and vaccines.This paper aims to describe the NITAG in Israel. The Israeli NITAG was established by the Ministry of Health in1974. The NITAG's full formal name is "the Advisory Committee on Infectious Diseases and Immunizations in Israel". The NITAG is charged with prioritizing choices while granting maximal significance to the national public health considerations. Since 2007, the full minutes of the NITAG's meetings have been publicly available on the committee's website (at the Ministry of Health website, in Hebrew).According to the National Health Insurance Law, all residents of Israel are entitled to receive universal health coverage. The health services basket includes routine childhood immunizations, as well as several adult and post - exposure vaccinations. The main challenge currently facing the NITAG is establishing a process for introducing new vaccines and updating the vaccination schedule through the annual update of the national health basket. In the context of the annual update, vaccines have to "compete" with multiple medications and technologies which are presented to the basket committee for inclusion in the national health basket. Over the years, the Israeli NITAG's recommendations have proved essential for vaccine introduction and scheduling and for communicable diseases control on a national level. The NITAG has established structured and transparent working processes and a decision framework according to WHO standards, which is evidence-based and country-specific to Israel.The recent global COVID-19 pandemic is a major concern for all countries as well as a challenge for NITAGs. Currently, the NITAGs have a key role in advising both on sustainment of the routine immunization programs and on planning of the COVID-19 vaccination campaigns, with ongoing updates and collaboration with the Ministry of Health and health organizations.

COVID-19, varying genetic resistance to viral disease and immune tolerance checkpoints

Coronavirus disease 2019 (COVID‐19) is a zoonosis like most of the great plagues sculpting human history, from smallpox to pandemic influenza and human immunodeficiency virus. When viruses jump into a new species the outcome of infection ranges from asymptomatic to lethal, historically ascribed to “genetic resistance to viral disease.” People have exploited these differences for good and bad, for developing vaccines from cowpox and horsepox virus, controlling rabbit plagues with myxoma virus and introducing smallpox during colonization of America and Australia. Differences in resistance to viral disease are at the core of the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) crisis, yet our understanding of the mechanisms in any interspecies leap falls short of the mark. Here I review how the two key parameters of viral disease are countered by fundamentally different genetic mechanisms for resistance: (1) virus transmission, countered primarily by activation of innate and adaptive immune responses; and (2) pathology, countered primarily by tolerance checkpoints to limit innate and adaptive immune responses. I discuss tolerance thresholds and the role of CD8 T cells to limit pathological immune responses, the problems posed by tolerant superspreaders and the signature coronavirus evasion strategy of eliciting only short‐lived neutralizing antibody responses. Pinpointing and targeting the mechanisms responsible for varying pathology and short‐lived antibody were beyond reach in previous zoonoses, but this time we are armed with genomic technologies and more knowledge of immune checkpoint genes. These known unknowns must now be tackled to solve the current COVID‐19 crisis and the inevitable zoonoses to follow.

Surveillance optimisation to detect poliovirus in the pre-eradication era: a modelling study of England and Wales

Surveillance for acute flaccid paralysis (AFP) cases are essential for polio eradication. However, as most poliovirus infections are asymptomatic and some regions of the world are inaccessible, additional surveillance tools require development. Within England and Wales, we demonstrate how inclusion of environmental sampling (ENV) improves the sensitivity of detecting both wild and vaccine-derived polioviruses (VDPVs) when compared to current surveillance. Statistical modelling was used to estimate the spatial risk of wild and VDPV importation and circulation in England and Wales. We estimate the sensitivity of each surveillance mode to detect poliovirus and the probability of being free from poliovirus, defined as being below a pre-specified prevalence of infection. Poliovirus risk was higher within local authorities in Manchester, Birmingham, Bradford and London. The sensitivity of detecting wild poliovirus within a given month using AFP and enterovirus surveillance was estimated to be 0.096 (95% CI 0.055–0.134). Inclusion of ENV in the three highest risk local authorities and a site in London increased surveillance sensitivity to 0.192 (95% CI 0.191–0.193). The sensitivity of ENV strategies can be compared using the framework by varying sites and the frequency of sampling. The probability of being free from poliovirus slowly increased from the date of the last case in 1993. ENV within areas thought to have the highest risk improves detection of poliovirus, and has the potential to improve confidence in the polio-free status of England and Wales and detect VDPVs.

Dynamics of Drug Resistance: Optimal Control of an Infectious Disease

Antimicrobial resistance is a significant public health threat. In the U.S. alone, 2 million people are infected and 23,000 die each year from antibiotic resistant bacterial infections. In many cases, infections are resistant to all but a few remaining drugs. We examine the case where a single drug remains and solve for the optimal treatment policy for an SIS infectious disease model incorporating the effects of drug resistance. The problem is formulated as an optimal control problem with two continuous state variables, the disease prevalence and drug's "quality" (the fraction of infections that are drug-susceptible). The decision maker's objective is to minimize the discounted cost of the disease to society over an infinite horizon. We provide a new generalizable solution approach that allows us to thoroughly characterize the optimal treatment policy analytically. We prove that the optimal treatment policy is a bang-bang policy with a single switching time. The action/inaction regions can be described by a single boundary that is strictly increasing when viewed as a function of drug quality, indicating that when the disease transmission rate is constant, the policy of withholding treatment to preserve the drug for a potentially more serious future outbreak is not optimal. We show that the optimal value function and/or its derivatives are neither C ¹ nor Lipschitz continuous suggesting that numerical approaches to this family of dynamic infectious disease models may not be computationally stable. Furthermore, we demonstrate that relaxing the standard assumption of constant disease transmission rate can fundamentally change the shape of the action region, add a singular arc to the optimal control, and make preserving the drug for a serious outbreak optimal. In addition, we apply our framework to the case of antibiotic resistant gonorrhea.

What is the importance of vaccine hesitancy in the drop of vaccination coverage in Brazil?

The successful Programa Nacional de Imunizações do Brasil (Brazilian National Immunization Program) has been experiencing a major challenge with regard to vaccination coverage for children, which has been dropping. Several aspects are related, but certainly vaccine hesitancy has been strengthening itself as one of the main concerns of Brazilian public administrators and researchers. Vaccine hesitancy is the delay in acceptance or refusal despite having the recommended vaccines available in health services, being a phenomenon that varies over time, over location and over types of vaccines. Hesitant individuals are between the two poles of total acceptance and refusal of vaccination. Vaccine hesitancy is nothing new in European and North-American countries, and even in Brazil, it has been studied even if under another name. The drop of vaccination coverage observed from 2016 on reiterates the relevance of the theme, which must be better understood through scientific research.

Successes and challenges of expansion of environmental poliovirus surveillance in the WHO South-East Asia Region

The last decade has witnessed an exponential expansion of environmental surveillance (ES) of poliovirus in sewage samples in the World Health Organization (WHO) South-East Asia Region. This has grown from only three sites in Mumbai, India in 2001 to 56 sites in 2017 in Bangladesh, India, Indonesia, Myanmar, Nepal and Thailand. ES is critical to the region in providing evidence of silent transmission of vaccine-derived poliovirus and Sabin-like poliovirus type 2 - especially since the global "switch" to cease use of oral polio vaccine type 2 - and for monitoring the effectiveness of containment activities. This targeted expansion of ES to supplement surveillance for acute flaccid paralysis (AFP) required quality assurance in ES procedures, improvements in the sensitivity of the laboratory-based surveillance system, and establishment of real-time data analysis for evidence-based programmes. ES in the region has provided documentary evidence for the absence of indigenous wild poliovirus in circulation and no importations via international travellers. Post-switch, while no vaccine-derived poliovirus was detected from AFP cases, ES identified five ambiguous vaccine-derived polioviruses in 2016 and early 2017, with no evidence of circulation. Future challenges include monitoring for vaccine-derived poliovirus strains shed for a prolonged time by immunodeficient individuals, and expanding ES to areas lacking sewage networks. To maintain the polio-free status of the WHO South-East Asia Region and achieve a world free of poliomyelitis, critical evaluation of immunization coverage, continued performance of surveillance for acute flaccid paralysis, and enhanced analysis of sewage samples to detect any breach in containment are essential.

Reintroducing OPV in Israel on the journey to global polio eradication - Estimation at a low rate of contraindicated population

INTRODUCTION

The 2013 reemergence of wild poliovirus in Israel led to the reinstatement of a routine OPV vaccination. Fearing VAPP in immunocompromised, the MOH regulated contraindications for vaccination candidates and household contacts. In this study we estimate the size of the contraindicated population to OPV vaccination.

METHOD

We studied vaccination candidates aged 2-9 and 14-23 months and probable household contacts. Using the rate of contraindications extracted for each study group from a medical records database, a statistical model was built to estimate the probability of contraindications in candidates.

RESULTS

3.9% of the 2-9-month-old study group and 4% of the 14-23-month-old group had contraindications by either self or household contacts.

CONCLUSION

A statistical model can provide an estimation of the contraindicated population and can be used in the future when devising vaccination campaigns. In contrast to concerns raised by the MOH, our findings show a smaller than anticipated contraindicated population.