Development and Evaluation of an Enzyme-Linked Immunosorbent Assay Targeting Rabies-Specific IgM and IgG in Human Sera.

Immunity from rabies depends on rabies virus neutralizing antibodies (RVNA) induced after immunization; however, the influence of antibody isotype switching has not been extensively investigated. This has become particularly relevant with changes in World Health Organization (WHO) recommended rabies vaccine regimens that may influence RVNA isotype kinetics, potentially affecting the peak, and longevity, of RVNA immunoglobulin (IgG) levels. We developed rapid and reliable assays for quantifying the anti-rabies IgM/IgG class switch in human serum based on an indirect ELISA technique. The immune response was tracked in ten individuals naïve to the rabies vaccine by quantifying serum titers weekly, from day seven to day 42 post-immunization, using a serum neutralization assay and the ELISA IgM/IgG assays. The average RVNA IU/mL levels were at D0 ≤ 0.1, D7 0.24, D14 8.36, D21 12.84, D28 25.74 and D42 28.68. Levels of specific IgM antibodies to rabies glycoprotein (EU/mL) were higher, on average, at D7, 1.37, and from D14, 5.49, to D21, 6.59. In contrast, average IgG antibodies (EU/mL) predominated from D28, 10.03, to D42, 14.45. We conclude that levels of anti-rabies IgM/IgG at D28 characterize the isotype class switch. These assays, combined with serum neutralization assays, distinguished the RVNA levels in terms of the IgM/IgG responses and are expected to add to the diagnostic repertoire, provide additional information in establishing rabies vaccine regimens, both post- and pre-exposure prophylaxis, and contribute to research efforts.

Correction: Briggs, D.J.; Moore, S.M. The Route of Administration of Rabies Vaccines: Comparing the Data. Viruses 2021, 13, 1252.

The authors wish to make the following corrections to this paper [...].

Robust humoral immune response against rabies virus in rabbits and guinea pigs immunized with plasmid DNA vectors encoding rabies virus glycoproteins - An approach to the production of polyclonal antibody reagents.

DNA-based immunization has been previously shown to be an efficient approach to induce robust immunity against infectious diseases in animals and humans. The advantages of DNA vaccines are simplicity of their construction and production, low cost, high stability, and ability to elicit a full spectrum of immune responses to target antigens. The goals of this study were (i) to assess the antibody immune response to rabies virus glycoproteins (rGPs) in rabbits and guinea pigs after intramuscular immunization with pTargeT and pVAC2-mcs mammalian expression vectors encoding either the wild-type (WT) or codon-optimized (cOPT) rGP genes; and (ii) to prepare in-house rabbit anti-rGP polyclonal antibody reagents suitable for in Single Radial Immunodiffusion (SRID) and Indirect Fluorescent Antibody (IFA) assays. The maximum antibody responses against rabies virus in rabbits and guinea pigs were observed after immunization series with 500 µg/dose of pVAC2-mcs vector encoding either the WT or cOPT rGP genes adjuvanted with Emulsigen-D. No significant difference in the anti-rabies virus neutralizing antibody titers was observed in rabbits immunized with the WT and cOPT rGPs. The in-house rabbit anti-rGP polyclonal antibody reagents reacted comparable to the current reference reagents in SRID and IFA assays. The results of the study demonstrated that the DNA immunization of animals with the WT or cOPT rGPs is a promising approach to either induction of high anti-rabies virus neutralizing antibody titers in vivo or for production of polyclonal antibody reagents against rabies.

Use of a Modified Preexposure Prophylaxis Vaccination Schedule to Prevent Human Rabies: Recommendations of the Advisory Committee on Immunization Practices - United States, 2022.

Human rabies is an acute, progressive encephalomyelitis that is nearly always fatal once symptoms begin. Several measures have been implemented to prevent human rabies in the United States, including vaccination of targeted domesticated and wild animals, avoidance of behaviors that might precipitate an exposure (e.g., provoking high-risk animals), awareness of the types of animal contact that require postexposure prophylaxis (PEP), and use of proper personal protective equipment when handling animals or laboratory specimens. PEP is widely available in the United States and highly effective if administered after an exposure occurs. A small subset of persons has a higher level of risk for being exposed to rabies virus than does the general U.S. population; these persons are recommended to receive preexposure prophylaxis (PrEP), a series of human rabies vaccine doses administered before an exposure occurs, in addition to PEP after an exposure. PrEP does not eliminate the need for PEP; however, it does simplify the rabies PEP schedule (i.e., eliminates the need for rabies immunoglobulin and decreases the number of vaccine doses required for PEP). As rabies epidemiology has evolved and vaccine safety and efficacy have improved, Advisory Committee on Immunization Practices (ACIP) recommendations to prevent human rabies have changed. During September 2019-November 2021, the ACIP Rabies Work Group considered updates to the 2008 ACIP recommendations by evaluating newly published data, reviewing frequently asked questions, and identifying barriers to adherence to previous ACIP rabies vaccination recommendations. Topics were presented and discussed during six ACIP meetings. The following modifications to PrEP are summarized in this report: 1) redefined risk categories; 2) fewer vaccine doses in the primary vaccination schedule; 3) flexible options for ensuring long-term protection, or immunogenicity; 4) less frequent or no antibody titer checks for some risk groups; 5) a new minimum rabies antibody titer (0.5 international units [IUs]) per mL); and 6) clinical guidance, including for ensuring effective vaccination of certain special populations.

A One Medicine Mission for an Effective Rabies Therapy.

Despite the disease's long history, little progress has been made toward a treatment for rabies. The prognosis for patient recovery remains dire. For any prospect of survival, patients require aggressive critical care, which physicians in rabies endemic areas may be reluctant or unable to provide given the cost, clinical expertise required, and uncertain outcome. Systematic clinical research into combination therapies is further hampered by sporadic occurrence of cases. In this Perspective, we examine the case for a One Medicine approach to accelerate development of an effective therapy for rabies through the veterinary care and investigational treatment of naturally infected dogs in appropriate circumstances. We review the pathogenesis of rabies virus in humans and dogs, including recent advances in our understanding of the molecular basis for the severe neurological dysfunction. We propose that four categories of disease process need to be managed in patients: viral propagation, neuronal degeneration, inflammation and systemic compromise. Compassionate critical care and investigational treatment of naturally infected dogs receiving supportive therapy that mimics the human clinical scenario could increase opportunities to study combination therapies that address these processes, and to identify biomarkers for prognosis and therapeutic response. We discuss the safety and ethics of this approach, and introduce the Canine Rabies Treatment Initiative, a non-profit organization with the mission to apply a One Medicine approach to the investigation of diagnostic, prognostic, and therapeutic options for rabies in naturally infected dogs, to accelerate transformation of rabies into a treatable disease for all patients.

Lessons Learned from the Development and Demonstration of a PPE Inventory Monitoring System for US Hospitals.

An international system should be established to support personal protective equipment (PPE) inventory monitoring, particularly within the healthcare industry. In this article, the authors discuss the development and 15-week deployment of a proof-of-concept prototype that included the use of a Healthcare Trust Data Platform to secure and transmit PPE-related data. Seventy-eight hospitals participated, including 66 large hospital systems, 11 medium-sized hospital systems, and a single hospital. Hospitals reported near-daily inventory information for N95 respirators, surgical masks, and face shields, ultimately providing 159 different PPE model numbers. Researchers cross-checked the data to ensure the PPE could be accurately identified. In cases where the model number was inaccurately reported, researchers corrected the numbers whenever possible. Of the PPE model numbers reported, 74.2% were verified-60.5% of N95 respirators, 40.0% of face shields, and 84.0% of surgical masks. The authors discuss the need to standardize how PPE is reported, possible aspects of a PPE data standard, and standards groups who may assist with this effort. Having such PPE data standards would enable better communication across hospital systems and assist in emergency preparedness efforts during pandemics or natural disasters.

Rabies virus neutralizing activity, pharmacokinetics, and safety of the monoclonal antibody mixture SYN023 in combination with rabies vaccination: Results of a phase 2, randomized, blinded, controlled trial.

BACKGROUND: SYN023-002 is a randomized, blinded, controlled study comparing rabies virus neutralizing activity (RVNA) and safety of SYN023, a monoclonal anti-rabies antibody mixture, to human-serum derived anti-rabies immunoglobulin (RIG) when administered with commercially available vaccines to healthy adult volunteers. METHODS: Participants were randomized among 4 treatment groups (SYN023 + Imovax, SYN023 + RabAvert, HyperRab + Imovax, HyperRab + RabAvert). On Day 0, subjects received 1 dose of RIG (0.3 mg/kg SYN023 or 20 IU/mL HyperRab) and their first of 5 vaccine doses. The primary objective was to compare cumulative RVNA between SYN023 and HyperRab recipients. Secondary objectives were to compare safety and to assess SYN023 pharmacokinetics and immunogenicity. RESULTS: All 164 randomized subjects initiated treatment and were included in safety analyses. At least 34 subjects/treatment group received all treatment and had complete RVNA results, thus were included in the primary endpoint analysis. Mean RVNAs were approximately ten-fold higher in SYN023 recipients compared to HyperRab recipients until Day 14. From Day 14 onwards, mean RVNA was lower in SYN023 recipients, but remained above the RVNA level widely considered adequate (≥0.5 IU/mL) through Day 112 (study end). The point estimate of the cumulative RVNA (83.22% SYN023/HyperRab), but not the lower CI bound (90% CI: 66.06%, 104.83%), fell within the protocol-defined similarity margin. Each RIG + vaccine regimen appeared safe with mostly mild AEs and no serious or severe related events observed. Except injection site pain (22% HyperRab recipients vs. 6% SYN023 recipients), treatment-related AEs incidences were similar between RIGs. Anti-SYN023 antibodies were observed but had no apparent effects on PK or safety. CONCLUSIONS: SYN023 administered with commercially available vaccines provides adequate antibody coverage beginning earlier than other commercially available RIGs with an acceptable safety profile. Some suppression of vaccine response occurred, but RVNA levels ≥ 0.5 IU/mL were maintained throughout the relevant period. REGISTRATION: ClinicalTrials.gov #NCT02956746. FUNDING: Synermore biologics.

Applying the Social Vulnerability Index as a Leading Indicator to Protect Fire-Based Emergency Medical Service Responders' Health.

During emergencies, areas with higher social vulnerability experience an increased risk for negative health outcomes. However, research has not extrapolated this concept to understand how the workers who respond to these areas may be affected. Researchers from the National Institute for Occupational Safety and Health (NIOSH) merged approximately 160,000 emergency response calls received from three fire departments during the COVID-19 pandemic with the CDC's publicly available Social Vulnerability Index (SVI) to examine the utility of SVI as a leading indicator of occupational health and safety risks. Multiple regressions, binomial logit models, and relative weights analyses were used to answer the research questions. Researchers found that higher social vulnerability on household composition, minority/language, and housing/transportation increase the risk of first responders' exposure to SARS-CoV-2. Higher socioeconomic, household, and minority vulnerability were significantly associated with response calls that required emergency treatment and transport in comparison to fire-related or other calls that are also managed by fire departments. These results have implications for more strategic emergency response planning during the COVID-19 pandemic, as well as improving Total Worker Health® and future of work initiatives at the worker and workplace levels within the fire service industry.

Challenges of Rabies Serology: Defining Context of Interpretation.

The case fatality rate of rabies, nearly 100%, is one of the most unique characteristic of this ancient virus infection. The crucial role rabies virus neutralizing antibody plays in protection is both well established and explanation of why rabies serology is important. Various laboratory methods can and have been used but serum neutralization methods have long been the gold standard due to the ability to measure function (neutralization), however these methods can be difficult to perform for several reasons. Assays such as enzyme linked absorbance assays (ELISA), indirect fluorescence antibody (IFA) and more recently lateral flow methods are in use. Interpretation of results can be problematic, not only between methods but also due to modifications of the same method that can lead to misinterpretations. A common assumption in review of laboratory test results is that different methods for the same component produce comparable results under all conditions or circumstances. Assumptions and misinterpretations provide the potential for detrimental decisions, ranging from regulatory to clinically related, and most importantly what 'level' is protective. Review of the common challenges in performance and interpretation of rabies serology and specific examples illuminate critical issues to consider when reviewing and applying results of rabies serological testing.

The Route of Administration of Rabies Vaccines: Comparing the Data.

Cell culture rabies vaccines were initially licensed in the 1980s and are essential in the prevention of human rabies. The first post-exposure prophylaxis (PEP) vaccination regimen recommended by the World Health Organization (WHO) was administered intramuscularly over a lengthy three-month period. In efforts to reduce the cost of PEP without impinging on safety, additional research on two strategies was encouraged by the WHO including the development of less expensive production methods for CCVs and the administration of reduced volumes of CCVs via the intradermal (ID) route. Numerous clinical trials have provided sufficient data to support a reduction in the number of doses, a shorter timeline required for PEP, and the approval of the intradermal route of administration for PEP and pre-exposure prophylaxis (PreP). However, the plethora of data that have been published since the development of CCVs can be overwhelming for public health officials wishing to review and make a decision as to the most appropriate PEP and PreP regimen for their region. In this review, we examine three critical benchmarks that can serve as guidance for health officials when reviewing data to implement new PEP and PreP regimens for their region including: evidence of immunogenicity after vaccination; proof of efficacy against development of disease; and confirmation that the regimen being considered elicits a rapid anamnestic response after booster vaccination.

Safety, Pharmacokinetics, and Neutralizing Activity of SYN023, a Mixture of Two Novel Antirabies Monoclonal Antibodies Intended for Use in Postrabies Exposure Prophylaxis.

SYN023 is a mixture of 2 humanized monoclonal antirabies antibodies (CTB011, CTB012). Two first-in-human studies evaluated ascending intramuscular (IM) injected doses (Study SYN023-001; N = 15) and IM vs subcutaneous (SC) administration (Study SYN023-003; N = 35) in healthy adults. In both studies, end points were safety, pharmacokinetics (PK), pharmacodynamics/rabies virus neutralizing activity (RVNA), and immunogenicity (anti-SYN023 antibodies). Adverse events were mild and infrequent at all doses tested by IM injection (0.3 mg/kg, 1.0 mg/kg, 2.0 mg/kg), or by SC injection (0.3 mg/kg). There were no apparent trends in adverse event frequency or nature with increased dose or with administration route. Serum PK of SYN023 component antibodies appeared comparable to each other at each dose tested and when administered IM versus SC with serum exposure doubling over the second week after administration. At the lowest dose tested (0.3 mg/kg) by either IM or SC injection, RVNA levels exceeded the concentration generally accepted as protective against rabies (≥0.5 IU/mL) by day 1 after administration. Supra-inhibitory levels persisted >42 days. RVNA increased with higher doses. Anti-CTB011 and anti-CTB012 antibodies occurred with no apparent effect on PK or safety. These data support the potential use of SYN023 in antirabies postexposure prophylaxis.

Developing a methodology to collect empirical data that informs policy and practices for stockpiling personal protective equipment.

BACKGROUND: Personal protective equipment (PPE) are stockpiled across the nation to offset supply depletion during public health emergencies. Stockpiled PPE inventories vary across the United States by type, model, quantity, and the conditions in which they are stored. Over the past decade, federal, state, and local stockpile managers have had concerns for the viability of aging PPE. METHODS: To understand factors that may affect stockpiled PPE, we explored the breadth of stockpile storage conditions and respirator and surgical gown inventories through collaboration with the national PPE community, qualitative observations collected at 10 different US stockpiles, and by compiling stockpile PPE inventories and climate data from a convenience sample of US stockpiles. RESULTS: The aggregated inventory from 20 stockpiles is reported, accounting for approximately 53 million respirators. Most respirators (69% or 35.8 million) have been stored between 5 and 10 years. Upon visiting 10 stockpile facilities, we report on the storage conditions observed and summarize the storage environment data collected. CONCLUSIONS: This is the first study to identify common PPE types, inventories, and storage conditions across federal, state, and local government stockpile facilities as well as health care organization-managed caches. These findings will be leveraged to guide the development of sampling protocols for air-purifying respirators and surgical gowns in US stockpiles to understand the performance viability after long-term storage.

Lagging or leading? Exploring the temporal relationship among lagging indicators in mining establishments 2006-2017.

PROBLEM: Safety management literature generally categorizes key performance indicators (KPIs) as either leading or lagging. Traditional lagging indicators are measures related to negative safety incidents, such as injuries, while leading indicators are used to predict (and therefore can be used to prevent) the likelihood of future negative safety incidents. Recent theory suggests that traditional lagging indicators also possess characteristics of leading indicators, and vice versa, however empirical evidence is limited. METHOD: The current research investigated the temporal relationships among establishment-level injuries, near misses, and fatal events using injury and employment data from a sample of 24,910 mining establishments over a 12-year period. RESULTS: While controlling for employee hours worked, establishment-level reported injuries and near misses were associated with of future fatal events across the sample of mines and over the time period studied. Fatal events were also associated with increases in future reported near misses, providing evidence of a cyclic relationship between them. DISCUSSION: These findings challenge the strict categorization of injuries, near misses, and fatal events as lagging indicators. Practical applications: Understanding the KPIs that should be used to manage organizational safety, and how they can be used, is of critical practical importance. The results of the current study suggest that, depending on several considerations, metrics tied to negative safety incidents may be used to anticipate, and possibly prevent, future negative safety events.

The Influence of ß-1,3-1,6-Glucans on Rabies Vaccination Titers in Cats.

ß-glucans have been shown to stimulate the immune system in several animal species. The aim of this study was to evaluate the immune stimulation capacity of a fully formulated diet with ß-1,3-1,6-glucans in cats, by assessing the rabies antibody titer after vaccination. Thirty-five healthy cats were recruited. The cats were placed into two groups and fed a standard diet in accordance with body weight. One group had the ß-glucans incorporated into the diet; the other group served as the control group. After two weeks of dietary adjustment; the rabies vaccine (Imrab® 3 TF; Merial) was administered on days 0 and 21. Blood samples were taken on days 0, 21, and 42. Titers were determined with the rapid fluorescent foci inhibition test (RFFIT). Titers at days 21 and 42 were compared between the two groups in a linear mixed effects model. This study showed that the animals receiving the non-supplemented feed had higher post-vaccination rabies antibody titers. This indicates that, in contrast to other animal species, the ß-glucan supplemented diet did not have the expected positive effect on the rabies antibody titers in cats.

Rabies: Current Preventive Strategies.

Desensitization to rabies is a result of successfully eliminating canine rabies in the United States, which occurred in 2007; however, the need for mandatory rabies vaccination in pets remains. Rabies cases are rare in comparison with other vaccine-preventable diseases in companion animals; however, because it is a zoonotic disease with the highest case fatality rate of any infectious disease demands the establishment of strict laws for disease prevention. Preventive strategies include addressing current concerns in consideration of disease surveillance, appropriate vaccination recommendations, and local regulations protecting public health.

Interstitial Lung Diseases in the U.S. Mining Industry: Using MSHA Data to Examine Trends and the Prevention Effects of Compliance with Health Regulations, 1996-2015.

Given the recent increase in dust-induced lung disease among U.S. coal miners and the respiratory hazards encountered across the U.S. mining industry, it is important to enhance an understanding of lung disease trends and the organizational contexts that precede these events. In addition to exploring overall trends reported to the Mine Safety and Health Administration (MSHA), the current study uses MSHA's enforcement database to examine whether or not compliance with health regulations resulted in fewer mine-level counts of these diseases over time. The findings suggest that interstitial lung diseases were more prevalent in coal mines compared to other mining commodities, in Appalachian coal mines compared to the rest of the United States, and in underground compared to surface coal mines. Mines that followed a relevant subset of MSHA's health regulations were less likely to report a lung disease over time. The findings are discussed from a lung disease prevention strategy perspective.

Examining Factors that Influence the Existence of Heinrich's Safety Triangle Using Site-Specific H&S Data from More than 25,000 Establishments.

In the 1930s, Heinrich established one of the most prominent and enduring accident prevention theories when he concluded that high severity occupational safety and health (OSH) incidents are preceded by numerous lower severity incidents and near misses. Seventy-five years of theory expansion/interpretation includes two fundamental tenets: (1) the ratio of lower to higher severity incidents exists in the form of a "safety-triangle" and (2) similar causes underlie both high and low severity events. Although used extensively to inform public policy and establishment-level health and safety priorities, recent research challenges the validity of the two tenets. This study explored the validity of the first tenet, the existence of the safety triangle. The advantage of the current study is the use of a detailed, establishment-specific data set that evaluated over 25,000 establishments over a 13-year time period, allowing three specific questions to be explored: (1) Are an increased number of lower severity incidents at an establishment significantly associated with the probability of a fatal event over time? (2) At the establishment level, do the effects of OSH incidents on the probability of a fatality over time decrease as the degree of severity decreases-thereby taking the form of a triangle? and (3) Do distinct methods for delineating incidents by severity affect the existence of the safety triangle form? The answer to all three questions was yes with the triangle form being dependent upon how severity was delineated. The implications of these findings in regard to Heinrich's theory and OSH policy and management are discussed.