Current rabies vaccines and prophylaxis schedules: Preventing rabies before and after exposure

Preclinical animal models to evaluate therapeutic antiviral antibodies

Despite the availability of effective preventative vaccines and potent small-molecule antiviral drugs, effective non-toxic prophylactic and therapeutic measures are still lacking for many viruses. The use of monoclonal and polyclonal antibodies in an antiviral context could fill this gap and provide effective virus-specific medical interventions. In order to develop these therapeutic antibodies, preclinical animal models are of utmost importance. Due to the variability in viral pathogenesis, immunity and overall characteristics, the most representative animal model for human viral infection differs between virus species. Therefore, throughout the years researchers sought to find the ideal preclinical animal model for each virus. The most used animal models in preclinical research include rodents (mice, ferrets, …) and non-human primates (macaques, chimpanzee, ….). Currently, antibodies are tested for antiviral efficacy against a variety of viruses including different hepatitis viruses, human immunodeficiency virus (HIV), influenza viruses, respiratory syncytial virus (RSV), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and rabies virus. This review provides an overview of the current knowledge about the preclinical animal models that are used for the evaluation of therapeutic antibodies for the abovementioned viruses.

A Bioengineered Nanovesicle Vaccine Boosts T-B cell Interaction for Immunotherapy of Echinococcus multilocularis

Alveolar echinococcosis (AE) is a zoonotic parasitic disease, resulting from being infected with the metacestode larvae of the tapeworm Echinococcus multilocularis (E. multilocularis). Novel prophylactic and therapeutic interventions are urgently needed since the current chemotherapy displays limited efficiency in AE treatment. Bioengineered nano cellular membrane vesicles are widely used for displaying the native conformational epitope peptides because of their unique structure and biocompatibility. In this study, four T-cells and four B-cells dominant epitope peptides of E. multilocularis with high immunogenicity were engineered into the Vero cell surface to construct a membrane vesicle nanovaccine for the treatment of AE. The results showed that the nanovesicle vaccine can efficiently activate dendritic cells, induce specific T/B cells to form a mutually activated circuit, and inhibit E. multilocularis infection. This study presents for the first time a nanovaccine strategy that can completely eliminate the burden of E. multilocularis.

Atmospheric pollen concentrations and chronic obstructive pulmonary disease (COPD) patients visits in Beijing: time series analysis using a generalized additive model

To investigate the correlation between the daily visits of chronic obstructive pulmonary disease (COPD) patients in hospital clinic and pollen concentrations in Beijing. We collected daily visits of COPD patients of Beijing Shijitan Hospital from April 1st, 2019 to September 30th, 2019. The relationship between pollen concentrations and COPD patient number was analyzed with meteorological factors, time trend, day of the week effect and holiday effect being controlled by the generalized additive model of time series analysis. R4.1.2 software was applied to generate Spearman correlation coefficient, specific and incremental cumulative effect curves of relative risks as well as the response and three-dimensional diagrams for the exposure lag effect prediction. The fitting models were used to predict the lag relative risk and 95% confidence intervals for specific and incremental cumulative effects of specific pollen concentrations. The number of COPD patients was positively correlated with pollen concentration. When pollen concentration increased by 10 grains/1000 mm2, the peak value of the specific cumulative effect appeared on day0, with the effect gone on day4 and a lag time of 4 days observed, whereas the incremental cumulative effect's peak value was shown on day17, and the effect disappeared on day18, with a lag time of 18 days. The results showed that pollen concentration was not only positively correlated with the number of COPD patients, but also had a bimodal lag effect on COPD visits in the hospital at Beijing.

Persistence of Anti-Rabies Antibody Response in Horses Following Vaccination

Rabies is a fatal zoonotic disease affecting all mammalian species. It is caused by the rabies virus and is prevalent worldwide. Horses are not commonly infected with rabies but their vaccination is recommended due to the potential zoonotic risk. This study aimed to evaluate the duration of immunity following rabies vaccination in horses. A total of 126 serum samples were collected from 93 horses, vaccinated 6 to 91 months before sampling. Rabies-virus-neutralizing antibody (RVNA) levels were evaluated using the Rabies Fluorescent Focus Inhibition Test (RFFIT). A protective RVNA titer of above 0.5 IU/mL was found in 112 (88.9%) of the samples and 84 (90.3%) of the horses. Antibody titers declined over time (rho = -0.271, p = 0.002); however, there was no significant difference in antibody titers or the prevalence of unprotected horses between the time intervals following vaccination. Purebred horses had lower antibody titers (p = 0.024). The response to booster vaccination was inspected in ten horses, and increased antibody titers were found in eight of them. The results of this study demonstrate the prolonged persistence of protective immunity in horses following rabies vaccination, in some cases, for up to eight years. Therefore, the current annual vaccination strategy should be re-evaluated. A rate of 9.7% of poor responders should be considered from an epidemiological perspective in order to minimize the risk of emergence of the disease.

A single immunization with core-shell structured lipopolyplex mRNA vaccine against rabies induces potent humoral immunity in mice and dogs

The persistence and clinical consequences of rabies virus (RABV) infection have prompted global efforts to develop a safe and effective vaccines against rabies. mRNA vaccines represent a promising option against emerging and re-emerging infectious diseases, gaining particular interest since the outbreak of COVID-19. Herein, we report the development of a highly efficacious rabies mRNA vaccine composed of sequence-modified mRNA encoding RABV glycoprotein (RABV-G) packaged in core-shell structured lipopolyplex (LPP) nanoparticles, named LPP-mRNA-G. The bilayer structure of LPP improves protection and delivery of RABV-G mRNA and allows gradual release of mRNA molecules as the polymer degrades. The unique core-shell structured nanoparticle of LPP-mRNA-G facilitates vaccine uptake and demonstrates a desirable biodistribution pattern with low liver targeting upon intramuscular immunization. Single administration of low-dose LPP-mRNA-G in mice elicited potent humoral immune response and provided complete protection against intracerebral challenge with lethal RABV. Similarly, single immunization of low-dose LPP-mRNA-G induced high levels of virus-neutralizing antibody titers in dogs. Collectively, our data demonstrate the potential of LPP-mRNA-G as a promising next-generation rabies vaccine used in human and companion animals.

Single visit rabies pre-exposure prophylaxis: A literature review

BACKGROUND

The current WHO-recommended rabies pre-exposure prophylaxis (PrEP) are two-visit vaccination schedules, but there are studies suggesting that single visit schedules might be sufficient to prime the immunity.

METHODS

A literature review was conducted to retrieve and summarize published data on single visit rabies PrEP. PubMed database was screened for articles published between January 1st, 2003 and December 31st, 2022. The bibliographies of the articles chosen to undergo full text review and of the current major WHO publications on rabies were searched to find additional references, regardless of publication date. The primary outcome was the percentage of subjects having received rabies PrEP on single visit schedules who achieved antibody levels ≥0.5 IU/mL one week after post-exposure prophylaxis (PEP), regardless of the PEP regimen.

RESULTS

11 studies were selected for inclusion, totalling 935 subjects, of which 696 received a simulated PEP schedule. Of these 696, a serological test result on day 7 was available for 408 of them, and 406 subjects (99.51%) seroconverted after PEP without any difference regarding time delay between PrEP and PEP or the vaccination schedule used for PEP.

CONCLUSION

Single visit PrEP schedules seem to confer sufficient protection in most healthy individuals without immunocompromised status if a booster PEP is administered after a suspected rabies exposure. Further studies in real-life settings and in different age categories are needed to confirm this finding, which may increase the availability of vaccines and thus the accessibility of PrEP for vulnerable populations.

Unmodified rabies mRNA vaccine elicits high cross-neutralizing antibody titers and diverse B cell memory responses

Licensed rabies virus vaccines based on whole inactivated virus are effective in humans. However, there is a lack of detailed investigations of the elicited immune response, and whether responses can be improved using novel vaccine platforms. Here we show that two doses of a lipid nanoparticle-formulated unmodified mRNA vaccine encoding the rabies virus glycoprotein (RABV-G) induces higher levels of RABV-G specific plasmablasts and T cells in blood, and plasma cells in the bone marrow compared to two doses of Rabipur in non-human primates. The mRNA vaccine also generates higher RABV-G binding and neutralizing antibody titers than Rabipur, while the degree of somatic hypermutation and clonal diversity of the response are similar for the two vaccines. The higher overall antibody titers induced by the mRNA vaccine translates into improved cross-neutralization of related lyssavirus strains, suggesting that this platform has potential for the development of a broadly protective vaccine against these viruses.

Canine rabies: An epidemiological significance, pathogenesis, diagnosis, prevention, and public health issues

Rabies is a zoonotic disease caused by rabies virus of the genus Lyssa virus and family Rhabdoviridae. It affects all mammals and is prevalent throughout the world and endemic in many countries except in Islands like Australia and Antarctica. It is highly fatal, but preventable. Disease causes threat to public health because rabid dogs bite humans, resulting in thousands of deaths every year. Around 59,000 people die every year from rabies in the world. Dogs play a vital role in most of the human exposure in rabies endemic areas. Transmission of virus occurs through the bite of an infected dog. Disease is manifested by fatal nervous symptoms leading to paralysis and death. Direct fluorescent antibody technique is the gold standard for the diagnosis of the disease in animals and humans. Prevention of rabies involves the vaccination of dogs and humans before or after an exposure. This review describes the etiology, pathogenesis, diagnosis, its prevention and control strategies.

Implications of the antiviral drug favipiravir on rabies immunoglobulin for post-exposure prophylaxis of rabies in mice model with category III-like exposures

Rabies is a fatal zoonotic disease caused by the rabies virus (RABV), with almost 100% mortality if proper post-exposure prophylaxis (PEP), consisting of rabies immunoglobulin (RIG) and rabies vaccine, is not applied in a timely manner. However, this is challenged by the limited availability of RIG, especially in resource-constrained countries. In this study, we assessed the scope of the antiviral drug favipiravir to treat rabies-infected mice as an alternative to RIG. Category III-like wounds were induced in RABV-challenged mice treated with favipiravir instead of RIG in the PEP regimen. The use of favipiravir followed by rabies vaccine provided complete protection against rabies-related death in 100% of mice, even after RABV propagated to the central nervous system during infection. Additionally, the virus-neutralizing antibody titer in the favipiravir and vaccine group was significantly higher than that of the RIG and vaccine recipients. The use of favipiravir with rabies vaccine seemingly prevents fatal outcomes and even rescues the cases that already express clinical symptoms. A clinical trial of this approach is warranted, especially in countries with low RIG availability.

Analytical and Numerical Boundedness of a Model with Memory Effects for the Spreading of Infectious Diseases

In this study, an integer-order rabies model is converted into the fractional-order epidemic model. To this end, the Caputo fractional-order derivatives are plugged in place of the classical derivatives. The positivity and boundedness of the fractional-order mathematical model is investigated by applying Laplace transformation and its inversion. To study the qualitative behavior of the non-integer rabies model, two steady states and the basic reproductive number of the underlying model are worked out. The local and global stability is investigated at both the steady states of the fractional-order epidemic model. After analytic treatment, a structure-preserving numerical template is constructed to numerically solve the fractional-order epidemic model. Moreover, the positivity, boundedness and symmetry of the numerical scheme are examined. Lastly, numerical experiment and simulations are accomplished to substantiate the significant traits of the projected numerical design. Consequences of the study are highlighted in the closing section.

Long-term persistence of antibodies and boostability after rabies intradermal pre-exposure prophylaxis

BACKGROUND

Currently, there is limited data on long-term persistence of antibodies and boostability of intradermal (ID) rabies pre-exposure prophylaxis (PrEP) schedules. This study investigated travellers who received a primary ID PrEP schedule at least 5 years previously to determine the persistence of antibodies and subsequent antibody response after one 0.1-ml ID booster dose.

METHODS

Adults (age ≥ 18 years) who had previously received ID PrEP at a specialist travel medicine clinic in Brisbane, Australia were included. At Day 0, blood was collected for serology and one dose of 0.1-ml ID rabies vaccine (Verorab®) was administered. At Day 7, serology was repeated. At Day 14, participants were given results and enquired if they experienced adverse events following immunization (AEFIs). Antibodies were measured using Platelia Rabies II ELISA; levels ≥0.5 EU/mL were considered antibody-positive.

RESULTS

158 participants were included [64.6% female, median age at enrolment 56.4 years, interquartile range (IQR) 42.4-65.2 years], and median time since the primary ID PrEP was 8.5 years (IQR 6.9-11.7 years). The majority of participants (82.3%) were antibody-positive at Day 0. The proportion of participants who were antibody-positive at Day 0 was higher among those who were younger at primary vaccination (87.0% if aged<50 years, 75.8% of aged ≥50 years). The proportion of participants who were antibody-positive declined as median time since primary vaccination increased, though the trend was not statistically significant (p-trend = 0.187). All except one participant (99.4%) were antibody-positive after one ID booster dose. AEFIs were reported by 42.4% of participants and were mainly mild.

CONCLUSIONS

Rabies antibodies persist for many years after ID PrEP and can be rapidly boosted with a single ID dose. Future studies are needed to confirm that ID PrEP primes the immune system sufficiently so that boosters are not routinely needed, and only given in the event of a rabies-prone exposure.

Efficacy of one-dose intramuscular rabies vaccine as pre-exposure prophylaxis in travellers

BACKGROUND

Current guidelines for rabies pre-exposure prophylaxis (PrEP) recommend multiple vaccine doses. Travellers sometimes present for pre-travel consultation with insufficient time to complete standard PrEP schedules. We investigated the efficacy of one-dose intramuscular (IM) vaccine in priming the immune system (as PrEP) by measuring antibody response to simulated post-exposure prophylaxis (PEP).

METHODS

A quasi-experimental pre-post intervention clinical trial was conducted at a specialist travel clinic in Australia. Adults (≥18 years) without a history of rabies vaccination were included. At Visit 1, seronegative status was confirmed and one dose of 0.5 ml IM rabies vaccine (Verorab®) administered. At Visit 2 (≥60 days after Visit 1), serology was repeated and a simulated PEP dose (0.5 ml IM) given on this day and again 3 days later (Visit 3). Serology was repeated at Visit 4 (7 days after Visit 2).

RESULTS

A total of 94 antibody-negative participants were included (<50 years [n = 50]; ≥50 years [n = 44]). At Visit 2, 38.0 and 31.8% of participants aged <50 and ≥50 years were antibody-positive (≥0.5 EU/ml). At Visit 4, all participants were antibody-positive; 82.0 and 47.7% of participants aged <50 and ≥50 years had antibody levels >4 EU/ml, respectively.

CONCLUSIONS

One-dose IM vaccine was effective as PrEP for priming the immune system in both age groups, resulting in rapid development of antibodies 7 days after commencing simulated PEP. If there is insufficient time to complete a standard PrEP schedule, one-dose IM could be considered as an alternative schedule for short trips, rather than not offering travellers any doses at all.Clinical trials registration: ACTRN12619000946112.

Evaluation of rabies immunoglobulin administration status in China: a retrospective, cross-sectional study at a tertiary hospital in Beijing

This retrospective cross-sectional study included patients with category Ⅲ exposure to the rabies virus at a single center between January and December 2019. Exposure characteristics and clinical data were compared and statistically analyzed among groups willing and unwilling to receive RIG injection, and determinants of its administration were identified by stepwise multivariate logistic regression analyses. In total, 1,757 patients with category Ⅲ exposure were enrolled: 845 males (48.1%) and 912 females (51.9%; median age: 28 [9-50] years). Among them, 1,297 (73.8%) received RIG injection (median age: 28 [8-50] years) and 460 (26.2%) refused to receive the injection (median age: 25 [15-48] years). Patients aged 16-25 years (odds ratio [OR]=3.006, 95% confidence interval [CI]=1.957-4.619), 26-45years (OR=2.940, 95% CI=2.011-4.298), 46-55 years (OR=3.647, 95% CI=2.233-5.959) and over 56 years (OR=6.660, 95% CI=4.009-11.062); those with injuries caused by cats (OR=1.937, 95% CI=1.476- 2.542); and people with scratch (OR=3.319, 95% CI= 2.510-4.390), minor (OR=35.281, 95% CI=18.524-64.198), and moderate (OR=12.711, 95% CI=7.221-22.375) injuries were more likely to refuse injection. The RIG administration level in the settings studied herein is insufficient. Educational and awareness programs should be considered for rabies prevention, especially those targeted at people not injured by dogs, people with minor injuries, and the elderly.

Timing of Intradermal Rabies Pre-exposure Prophylaxis Injections: Immunological Effect on Vaccination Response

INTRODUCTION

Rabies remains a global threat, with annually over 59,000 deaths. Intradermal (ID) pre-exposure prophylaxis (PrEP) is very efficient and reduces the need for rabies immunoglobulins. Not much is known about factors that influence the immune response to ID administered rabies vaccine. The aim of this study is to determine if variations in timing of vaccine administration and serology determination, age and gender have an influence on the levels of rabies virus neutralizing antibody (RVNA) after ID rabies vaccination.

MATERIALS AND METHODS

This is a retrospective study based on electronic health record vaccination data of Belgian military personnel who received ID rabies PrEP with a three injections regimen during the period 2014-2017. Serology was determined by using the RFFIT method. Fischer's exacts tests were used to evaluate the effect of each independent variable on RVNA levels.

RESULTS

In this study, 2,112 subjects were included. All but one seroconverted with a RVNA level ≥0.5 IU/mL. About 48% of subjects developed an antibody titer of >10 IU/mL, 36% had antibody levels 3-10 IU/mL and 16% had an antibody level 0.5-2.99 IU/mL. Statistically significant (p = 0.0018) higher RVNA levels are observed in the groups that received vaccination doses later as planned. Timing of serology determination also influenced RVNA levels significantly (p = 0.000). Antibody levels were significantly higher in females than in males (p = 0.000). Age did influence RVNA levels significantly (p = 0.022).

CONCLUSIONS

Timing of vaccine dose administration, timing of serology testing, sex and age do significantly influence the humoral B-cell response to ID administered rabies vaccine.

Developing and evaluating an intervention to improve care and reduce costs of rabies postexposure therapy: an observational quality improvement initiative in selected vaccination units in Sri Lanka

BACKGROUND

Exposure to the rabies virus is fatal unless a patient is treated with a timely, accurate and complete administration of postexposure prophylaxis (PEP). The level of adherence to PEP guidelines by health service providers is therefore critical in providing high-quality care as well as preventing unnecessary costs.

METHODS

We developed a simple user-friendly decision aid based on Sri Lankan national guidelines for the administration of PEP and trialed it over a 5-month period in three study settings. Pre and post levels of adherence to the national guidelines by service providers was measured in each setting. Changes to per patient cost for rabies medications and hospital admissions were also collected.

RESULTS

A significant improvement in adherence to the guidelines was observed in two settings with a nonsignificant improvement observed in the third setting. We estimated a total cost saving of LKR 158 476 across the three sites, comprising LKR 14 418 in admissions cost savings and LKR 144 058 in medication savings.

CONCLUSION

We conclude that the development of a decision aid for the administration of PEP is likely to be an effective and cost-saving intervention in the Sri Lankan setting. Further research is required to inform the generalizability of our findings.

Preexposure Intradermal Rabies Vaccination: A Noninferiority Trial in Healthy Adults on Shortening the Vaccination Schedule From 28 to 7 Days

Background

The existing 4-week preexposure rabies vaccination schedule is costly and often not practicable. Shorter effective schedules would result in wider acceptance.

Methods

We conducted a noninferiority trial in 500 healthy adults comparing the safety and immunogenicity of a 2-visit (days 0 and 7) intradermal (ID) primary vaccination (2 doses of 0.1 mL ID of the human diploid cell culture rabies vaccine [HDCV] at days 0 and 7) vs a standard 3-visit schedule (single dose of 0.1 mL ID at days 0, 7, and 28). One year to 3 years after primary vaccination, a single booster dose of 0.1 mL ID of HDCV was given to evaluate the anamnestic rabies antibody response. The primary endpoint for immunogenicity was the percentage of subjects with an adequate antibody level >0.5 IU/mL 7 days after the booster injection. The safety endpoint was the proportion of participants developing adverse reactions following the primary vaccination and/or booster dose.

Results

All subjects in both study groups possessed a rabies antibody titer >0.5 IU/mL on day 7 following the booster dose. Following the booster dose, subjects exposed to the double-dose 2-visit ID schedule had a geometric mean titer of 37 IU/mL, compared with 25 IU/mL for the single-dose 3-visit schedule (P < .001). Local reactions at the injection site following primary vaccination were mild and transient.

Conclusions

In healthy adults, ID administration of a double dose of 0.1 mL of HDCV over 2 visits (days 0 and 7) was safe and not inferior to the single-dose 3-visit schedule.

Clinical Trials Registration

NCT01388985, EudraCT 2011-001612-62.

Seroconversion after three doses of intramuscular rabies vaccine as a post-exposure treatment

Rabies is still threatening half of the world's population with the global burden of canine rabies being estimated as 59,000 human deaths, annually. With no cure existing for clinical rabies, post-exposure prophylaxis (PEP) is the only certain means to save lives of the exposed people. In Iran, bite incidences exceed 180,000 per year, where all victims receive 5 vaccine doses for PEP, conforming to the Essen regimen. More than two-thirds of the exposed individuals stop receiving treatments after day 7, for the reason of being exposed to a non-rabid dog or cat. According to the national standard protocols, these individuals should re-start a complete 5-dose PEP course upon the re-exposure. New WHO recommendations based on scientific data is encouraging revisions to the existing prophylaxis programs. In order to know if an incomplete Essen regimen can provide adequate immunity, in the present study, 5 groups of individuals who had only received 3 first doses of the Essen regimen within the previous 1, 3, 6, 12 and 24 months were examined for immunity against rabies. Our results indicated sufficient anti-rabies neutralizing antibody in all individuals, before and after receiving two standard booster doses (i.e. days 0 and 3). This might also suggest the adequacy of the 3 first doses of vaccination, as a one-week long post-exposure vaccination program.

Understanding the basis of transcutaneous vaccine delivery

Under many circumstances, prophylactic immunizations are considered as the only possible strategy to control infectious diseases. Considerable efforts are typically invested in immunogen selection but, erroneously, the route of administration is not usually a major concern despite the fact that it can strongly influence efficacy. The skin is now considered a key component of the lymphatic system with tremendous potential as a target for vaccination. The purpose of this review is to present the immunological basis of the skin-associated lymphoid tissue, so as to provide understanding of the skin vaccination strategies. Several strategies are currently being developed for the transcutaneous delivery of antigens. The classical, mechanical or chemical disruptions versus the newest approaches based on microneedles for antigen delivery through the skin are discussed herein.

Nasal Reconstruction Following a Dog Bite

Bite wounds in the nose region may lead to serious esthetic problems and functional losses. The authors describe a dog bite to his nose, resulting in a defect involving the entire tip of the nose and a part of the surrounding subunits. He was repaired with forehead flap and auricular conchal cartilage acutely. To the authors' knowledge, there are very few cases of acute repair in the literature. The authors also made a literature review on this subject.

Descriptive assessment of rabies post-exposure prophylaxis procurement, distribution, monitoring, and reporting in four Asian countries: Bangladesh, Bhutan, Cambodia, and Sri Lanka, 2017-2018

BACKGROUND

There are approximately 35,000 human deaths from rabies in Asia annually. Rabies can be prevented through timely post-exposure prophylaxis (PEP) consisting of wound washing, rabies vaccine, and in some cases, rabies immunoglobulin (RIG). However, access to rabies PEP often remains limited to urban areas and is cost-prohibitive. There is little information on procurement, distribution, monitoring, and reporting of rabies PEP.

METHODS

We interviewed key informants in the public sector from various levels in Bangladesh, Bhutan, Cambodia, and Sri Lanka between March 2017 and May 2018 using a descriptive assessment tool to obtain information on procurement, distribution, monitoring, and reporting of rabies PEP. These four countries in Asia were chosen to showcase a range of rabies PEP systems. National rabies focal points were interviewed in each country and focal points helped identify additional key informants at lower levels.

RESULTS

A total of 22 key informants were interviewed at various levels (central level to health facility level) including national rabies focal points in each country. Each country has a unique system for managing rabies PEP procurement, distribution, monitoring, and reporting. There are varying levels of PEP access for those with potential rabies exposures. Rabies PEP is available in select health facilities throughout the country in Bangladesh, Bhutan, and Sri Lanka. In Cambodia, rabies PEP is limited to two urban centers. The availability of RIG in all four countries is limited. In these four countries, most aspects of the rabies PEP distribution system operate independently of systems for other vaccines. However, in Bhutan, rabies PEP and Expanded Programme on Immunization (EPI) vaccines share cold chain space in some locations at the lowest level. All countries have a monitoring system in place, but there is limited reporting of data, particularly to the central level.

CONCLUSION

Systems to procure, deliver, monitor, and report on rabies PEP are variable across countries. Sharing information on practices more widely among countries can help programs to increase access to this life-saving treatment.

Trying to treat the untreatable: experimental approaches to clear rabies virus infection from the CNS

Rabies virus causes an invariably fatal encephalitis following the onset of clinical disease. Despite the availability of safe and effective vaccines, the clinical stages of rabies encephalitis remain untreatable, with few survivors being documented. A principal obstacle to the treatment of rabies is the neurotropic nature of the virus, with the blood-brain barrier size exclusion limit rendering the delivery of antiviral drugs and molecules to the central nervous system inherently problematic. This review focuses on efforts to try and overcome barriers to molecule delivery to treat clinical rabies and overviews current progress in the development of experimental live rabies virus vaccines that may have future applications in the treatment of clinical rabies, including the attenuation of rabies virus vectors through either the duplication or mutation of existing genes or the incorporation of non-viral elements within the genome. Rabies post-infection treatment (PIT) remains the holy grail of rabies research.

Human rabies post exposure prophylaxis at the Pasteur Institute of Dakar, Senegal: trends and risk factors

BACKGROUND

Rabies remains a major public health problem in developing countries. Most fatal rabies cases, especially in children, result from dog bites and occur in low-income countries, such as those in Sub-Saharan Africa. Rabies can be controlled through mass dog vaccination and human deaths prevented through timely and appropriate post-exposure prophylaxis (PEP). As access to appropriate PEP remains a serious challenge for bite-victims, the aim of this study was to understand the use of PEP, to evaluate the knowledge, attitudes and practices with respect to rabies and to identify risk factors related to non-compliance with PEP to define recommendations for improving PEP in Senegal.

METHODS

This study included patients with suspicion of rabies exposure who sought PEP at the Pasteur Institute of Dakar from April 2013 to March 2014. Patients with rabies clinical symptoms, those who had already started PEP and those with exposure outside Senegal or for more than 3 months were excluded. Data on risk factors and propensity to seek and complete PEP were collected using questionnaires and phone interviews. The association between acceptability and compliance with PEP and other independent variables were evaluated using multivariate regression analysis.

RESULTS

Among the 905 patients enrolled into the study, 67% were male (sex ratio M/F, 2) and 46%, children under 15 years of age. Exposures by animal bites represented 87%, whereas the remainder were due to scratches or contact; 76% were classified as WHO category III and 88% were due to dogs. Among these patients, 7% refused to start PEP and 54.5% completed the full schedule. Main factors reported by non-compliant patients were vaccine costs and affordability, and knowledge on status of biting animal.

CONCLUSION

This study shows that despite the awareness about rabies dangers and prevention, only half of the patients completed the full PEP schedule. The following recommendations, such as free of charge prophylaxis or intradermal regimens as an alternative to intramuscular regimens, should be considered to increase the adherence to PEP at the Pasteur Institute of Dakar and in Senegal.

Bats and Viruses: Emergence of Novel Lyssaviruses and Association of Bats with Viral Zoonoses in the EU

Bats in the EU have been associated with several zoonotic viral pathogens of significance to both human and animal health. Virus discovery continues to expand the existing understating of virus classification, and the increased interest in bats globally as reservoirs or carriers of zoonotic agents has fuelled the continued detection and characterisation of new lyssaviruses and other viral zoonoses. Although the transmission of lyssaviruses from bat species to humans or terrestrial species appears rare, interest in these viruses remains, through their ability to cause the invariably fatal encephalitis—rabies. The association of bats with other viral zoonoses is also of great interest. Much of the EU is free of terrestrial rabies, but several bat species harbor lyssaviruses that remain a risk to human and animal health. Whilst the rabies virus is the main cause of rabies globally, novel related viruses continue to be discovered, predominantly in bat populations, that are of interest purely through their classification within the lyssavirus genus alongside the rabies virus. Although the rabies virus is principally transmitted from the bite of infected dogs, these related lyssaviruses are primarily transmitted to humans and terrestrial carnivores by bats. Even though reports of zoonotic viruses from bats within the EU are rare, to protect human and animal health, it is important characterise novel bat viruses for several reasons, namely: (i) to investigate the mechanisms for the maintenance, potential routes of transmission, and resulting clinical signs, if any, in their natural hosts; (ii) to investigate the ability of existing vaccines, where available, to protect against these viruses; (iii) to evaluate the potential for spill over and onward transmission of viral pathogens in novel terrestrial hosts. This review is an update on the current situation regarding zoonotic virus discovery within bats in the EU, and provides details of potential future mechanisms to control the threat from these deadly pathogens.

Dog bite injuries of the eye and ocular adnexa

Dog bites result in a diverse range of injuries and complications in the periocular region, particularly in school aged children. It is therefore incumbent on the oculoplastic surgeon to be well versed in both acute and long-term management. The intent of this review is to provide a systematic evaluation of the epidemiology, principles of dog bite wound care, and specific considerations related to common patterns of ophthalmic injury. Review of clinical literature from 1976 to 2014. The majority of periocular injuries result from seemingly benign interactions between young children and familiar dogs. Aggressive saline lavage combined with selective debridement of devitalized tissue is essential. High-risk wounds and vulnerable patient groups may benefit from preventive antibiotic coverage as well as appropriate rabies and tetanus prophylaxis. While the nuances of surgical repair are variable given the heterogeneity of presentation, systematic examination and an algorithm-driven approach underlie the optimal management of these complex injuries.

A high throughput neutralization test based on GFP expression by recombinant rabies virus

The effectiveness of rabies vaccination in both humans and animals is determined by the presence of virus neutralizing antibodies (VNAs). The Rapid Fluorescent Focus Inhibition Test (RFFIT) is the method traditionally used for detection and quantification of VNAs. It is a functional in vitro test for assessing the ability of antibodies in serum to bind and prevent infection of cultured cells with rabies virus (RABV). The RFFIT is a labor intensive, low throughput and semi-quantitative assay performed by trained laboratorians. It requires staining of RABV-infected cells by rabies specific fluorescent antibodies and manual quantification of fluorescent fields for titer determination. Although the quantification of fluorescent fields observed in each sample is recorded, the corresponding images are not stored or captured to be used for future analysis. To circumvent several of these disadvantages, we have developed an alternative, automated high throughput neutralization test (HTNT) for determination of rabies VNAs based on green fluorescent protein (GFP) expression by a recombinant RABV and compared with the RFFIT. The HTNT assay utilizes the recombinant RABV ERA variant expressing GFP with a nuclear localization signal (NLS) for efficient quantification. The HTNT is a quantitative method where the number of RABV-infected cells are determined and the images are stored for future analysis. Both RFFIT and HTNT results correlated 100% for a panel of human and animal positive and negative rabies serum samples. Although, the VNA titer values are generally agreeable, HTNT titers tend to be lower than that of RFFIT, probably due to the differences in quantification methods. Our data demonstrates the potential for HTNT assays in determination of rabies VNA titers.

The potency of rabies vaccine is demonstrated by the presence of virus neutralizing antibodies (VNAs) in serum. It is critical to evaluate immunologic status of individuals who work directly with rabies virus (RABV) (laboratorians) or at high risk of infection due to interaction with animals (veterinarians and animal control workers). In addition, rabies vaccination records and demonstration of VNAs in animals are mandatory before initiating pet travel to rabies-free counties or regions. Rabies VNAs are currently determined by the rapid fluorescent focus inhibition test (RFFIT) and the fluorescent antibody virus neutralization (FAVN) test, which measure the ability of antibodies to bind and prevent infection of RABV in vitro. Both assays require staining of infected cells using anti-rabies antibodies and manual observation of infected cells by a fluorescent microscope to determine VNA titers. In this study, we have developed a GFP reporter-based high throughput neutralization test (HTNT) for automated quantification of infected cells. This method has the advantages of allowing investigators to analyze and store the results, and can accommodate large sample sizes. Overall, the results from HTNT exhibited 100% correlation with that of RFFIT, albeit with differences in rabies VNA titer values due to quantification methods.

Recent advances in the development of monoclonal antibodies for rabies post exposure prophylaxis: A review of the current status of the clinical development pipeline

Despite successful control in many parts of the world, rabies virus continues to result in tens of thousands of deaths each year. Death from rabies can be prevented by timely and appropriate post exposure prophylaxis including wound cleaning and administration of vaccine and rabies immunoglobulin. Currently, rabies immunoglobulin is derived from the blood plasma of horses or humans and has several limitations relating to supply, cost and quality. Monoclonal antibodies produced through recombinant DNA technologies could potentially overcome these limitations. The first anti-rabies monoclonal antibody has recently gained regulatory approval in India and there are several other candidates being evaluated in clinical trials. Given the advances in the field, rabies monoclonal antibodies have been recently considered by the World Health Organization's Strategic Advisory Group of Experts on Immunization and included in updated WHO immunization policy recommendations for rabies published in April 2018. This article reviews the current landscape of the clinical trial development of anti-rabies monoclonal antibodies and the historical clinical trial pathways followed for blood-derived rabies immunoglobulin before discussing challenges in the clinical evaluation, regulatory approval, uptake and monitoring of these products.

Global characteristics of the rabies biologics market in 2017

In 2017, the World Health Organization, the World Organisation for Animal Health, the Food and Agriculture Organization of the United Nations and the Global Alliance for Rabies control developed a strategic plan to end human rabies deaths by 2030.

A survey for manufacturing capacity and product characteristics of rabies biologics was conducted to inform this process. Twenty-three of 42 manufacturers, responded, giving a market capacity for 2017 of 90 million vials for human vaccines, 2.5 million vials for rabies immunoglobulins, 2 million vials for monoclonal antibodies and 181 million vials for dog vaccines.

Production capacity could be increased by many manufacturers but was limited by country demand, lack of long-term planning and restricted market expansion. Should countries implement national rabies elimination programmes where biologic needs are forecasted and production lead times respected, manufacturers can meet future supply needs towards global elimination of human dog-mediated rabies deaths.

Recombinant Monoclonal Antibodies for Rabies Post-exposure Prophylaxis

Rabies virus is a prototypical neurotropic virus that causes one of the most dangerous zoonotic diseases in humans. Humanized or fully human monoclonal antibodies (mAb) that neutralize rabies virus would be the basis for powerful post-exposure prophylaxis of rabies in humans, having several significant benefits in comparison with human or equine rabies polyclonal immunoglobulins. The most advanced antibodies should broadly neutralize natural rabies virus isolates, bind with conserved antigenic determinants of the rabies virus glycoprotein, and show high neutralizing potency in assays in vivo. The antibodies should recognize nonoverlapping epitopes if they are used in combination. This review focuses on basic requirements for anti-rabies therapeutic antibodies. The urgency in the search for novel rabies post-exposure prophylaxis and methods of development of anti-rabies human mAb cocktail are discussed. The rabies virus structure and pathways of its penetration into the nervous system are also briefly described.

Single visit rabies pre-exposure priming induces a robust anamnestic antibody response after simulated post-exposure vaccination: results of a dose-finding study

BACKGROUND

The current standard 3-dose intramuscular rabies PrEP schedule suffers from a number of disadvantages that severely limit accessibility and availability. The cost of is often prohibitive, it requires 3 visits to the clinic, and there are regular vaccine shortages.

METHODS

Volunteers ( N  = 30) were randomly assigned to 4 study arms: 1 standard dose intramuscular (IM) dose of PVRV (purified Vero cell rabies vaccine, Verorab), and 1/5th, 2/5th or 3/5th- fractional intradermal (ID) dose of PVRV in a single visit. All subjects received a simulated rabies post-exposure prophylaxis (D0, D3) 1 year later. Rabies virus neutralizing antibodies (RVNA) were determined by virus neutralization microtest (FAVN) on D0, D7, D28, Y1 and Y1 + D7.

RESULTS

28 out of 30 subjects (93%) seroconverted 1 month after primary vaccination; 1 subject in the 1-dose IM arm and 1 in the 1/5th-fractional dose ID arm did not. After 1 year, 22 out of 30 subjects (73%) no longer had RVNA above 0.5 IU/ml, with no discernible difference between study groups. After 1 year, all 30 subjects mounted a booster response within 7 days after simulated PEP, with the highest titers found in the single dose IM group ( P  < 0.03).

CONCLUSIONS

This dose finding study demonstrates that priming with a single dose of rabies vaccine was sufficient to induce an adequate anamnestic antibody response to rabies PEP in all subjects 1 year later, even in those in whom the RVNA threshold of 0.5 IU/ml was not reached after priming.

The impact of novel lyssavirus discovery

The global discovery of novel lyssaviruses is of continued scientific interest through its importance to both public and animal health. Lyssaviruses cause an invariably fatal encephalitis that is more commonly known as rabies. The term rabies has a long history in human society, as rabies virus (RABV) is the only pathogen that is associated with 100% fatality once the onset of clinical disease has started. Although predominantly associated across the globe with domestic and feral dog populations, the association of bats is clear. Whilst evolutionarily associated with bats, RABV is most commonly transmitted to human populations through the bite of an infected dog and dogs are considered the primary reservoir of disease. Indeed, RABV does cause more than an estimated 70000 deaths every year globally in human populations and whilst this is largely in areas where the disease is endemic, areas that remain free of rabies must remain vigilant to the risk of re-incursion of disease. Characterisation of novel lyssaviruses is of importance on several levels. Not least to investigate the pathogenesis and potential transmission routes of different lyssavirus species but also to assess the potential effect of post-exposure treatments and vaccination should human exposure occur. Bat lyssaviruses and the problems associated with novel discoveries and the potential impact they have on both human and animal populations are discussed.

Safety comparison of four types of rabies vaccines in patients with WHO category II animal exposure: An observation based on different age groups

To evaluate the safeties of 4 types of rabies vaccines for patients with WHO category II animal exposure, especially in different age groups.A total of 4000 patients with WHO category II animal exposure were randomly divided into 4 vaccine groups, and were respectively given with Vaccines A, B, C, and D. And subjects in each vaccine group were divided into 4 age groups (≤5, 5-18, 19-60, and ≥60-year-old groups). Then adverse events (including local and systemic ones) were recorded and compared. Consequently, except for Vaccine B, patients under the age of 5 in Groups A, C, and D suffered from more adverse reactions than those in other age groups. Furthermore, for the children aged less than 5 years, incidence of adverse events following administration of Vaccine B, with the dose of 0.5 mL and production of bioreactor systems, was significantly lower than Vaccines A and D.Our data showed that rabies vaccines with smaller doses and more advanced processing techniques are of relatively high safety for the patients, especially for the young children.

Current Developments and Future Prospects for Plant-Made Biopharmaceuticals Against Rabies

Rabies is a prevalent health problem in developing countries. Although vaccines and immunoglobulin treatments are available, their cost and multiple-dose treatments restrict availability. During the last two decades, plants have served as a low-cost platform for biopharmaceuticals production and have been applied to fight against rabies during the last two decades. Herein, I provide a description of the state of the art in the development of plant-made pharmaceuticals against rabies and identify key prospects for the field in terms of novel strategies, immunogen design, and therapeutic antibodies production.

Should travellers to rabies-endemic countries be pre-exposure vaccinated? An assessment of post-exposure prophylaxis and pre-exposure prophylaxis given to Danes travelling to rabies-endemic countries 2000-12

BACKGROUND

Since 2000, a steady increase of vaccines used for both rabies Post-exposure prophylaxis (PEP) and rabies Pre-exposure prophylaxis (PrEP) given to Danish travellers was observed. This study aims to evaluate whether the increase of PEP and PrEP was due to increased travelling, increased awareness of the need for PrEP, or more animal bites per travel, leading to more PEP being administered, in order to assess the need for changing the recommendations. We also described in which countries Danish travelers most frequently reported possible exposure to rabies, and evaluated the timeliness of rabies PEP, including rabies immunoglobulin (RIG).

METHODS

We included all Danes reported to the National Database for Rabies Treatment as having started rabies PEP either abroad or after returning to Denmark, between 2000 and 2012. Data on the yearly number of Danish travelers from 2004 to 2012 to Thailand were collected to calculate the incidence of animal bites at this destination. We also included data on rabies vaccines sold for PrEP or for booster vaccination in Denmark.

RESULTS

PEP after possible exposure to rabies abroad increased yearly by 8.8 %. Likewise vaccines sold for PrEP increased by 8.2% annually. The number of Danish travelers to Thailand increased by 7.3% per year, resulting in a stable incidence of animal bites per 100,000 travelers. Seventy-five % started PEP in the country of exposure, while only 10 % received RIG.

CONCLUSIONS

The yearly increase in PEP and PrEP are parallel to the yearly increase in number of travelers, and can thus be explained by the increased rate of traveling, and not by a rise in awareness of rabies risk or more bites per traveler.Even short term travelers should be given the option of including PrEP in their travel immunisation program, as PEP and especially RIG is not always available in rabies-endemic countries.

Sudden onset unilateral sensorineural hearing loss after rabies vaccination

A 33-year-old man developed profound sudden onset right-sided hearing loss with tinnitus and vertigo, within 24 h of pretravel rabies vaccination. There was no history of upper respiratory tract infection, systemic illness, ototoxic medication or trauma, and normal otoscopic examination. Pure tone audiograms (PTA) demonstrated right-sided sensorineural hearing loss (thresholds 90-100 dB) and normal left-sided hearing. MRI internal acoustic meatus, viral serology (hepatitis B, C, HIV and cytomegalovirus) and syphilis screen were normal. Positive Epstein-Barr virus IgG, viral capsid IgG and anticochlear antibodies (anti-HSP-70) were noted. Initial treatment involved a course of high-dose oral prednisolone and acyclovir. Repeat PTAs after 12 days of treatment showed a small improvement in hearing thresholds. Salvage intratympanic steroid injections were attempted but failed to improve hearing further. Sudden onset sensorineural hearing loss (SSNHL) is an uncommon but frightening experience for patients. This is the first report of SSNHL following rabies immunisation in an adult.

Animal-associated exposure to rabies virus among travelers, 1997-2012

No demographic characteristics identified who might benefit most from pretravel counseling.

Among travelers, rabies cases are rare, but animal bites are relatively common. To determine which travelers are at highest risk for rabies, we studied 2,697 travelers receiving care for animal-related exposures and requiring rabies postexposure prophylaxis at GeoSentinel clinics during 1997–2012. No specific demographic characteristics differentiated these travelers from other travelers seeking medical care, making it challenging to identify travelers who might benefit from reinforced pretravel rabies prevention counseling. Median travel duration was short for these travelers: 15 days for those seeking care after completion of travel and 20 days for those seeking care during travel. This finding contradicts the view that preexposure rabies vaccine recommendations should be partly based on longer travel durations. Over half of exposures occurred in Thailand, Indonesia, Nepal, China, and India. International travelers to rabies-endemic regions, particularly Asia, should be informed about potential rabies exposure and benefits of pretravel vaccination, regardless of demographics or length of stay.

Operational performance and analysis of two rabies vaccination campaigns in N'Djamena, Chad

Transmission of rabies from animals to people continues despite availability of good vaccines for both human and animal use. The only effective strategy to achieve elimination of dog rabies and the related human exposure is to immunize dogs at high coverage levels. We present the analysis of two consecutive parenteral dog mass vaccination campaigns conducted in N'Djamena in 2012 and 2013 to advocate the feasibility and effectiveness for rabies control through proof of concept. The overall coverage reached by the intervention was >70% in both years. Monthly reported rabies cases in dogs decreased by more than 90% within one year. Key points were a cooperative collaboration between the three partner institutions involved in the control program, sufficient information and communication strategy to access local leaders and the public, careful planning of the practical implementation phase and the effective motivation of staff. The dynamic and semi to non-restricted nature of dog populations in most rabies endemic areas is often considered to be a major obstacle to achieve sufficient vaccination coverage. However, we show that feasibility of dog mass vaccination is highly dependent on human determinants of dog population accessibility and the disease awareness of dog owners. Consequently, prior evaluation of the human cultural and socio-economic context is an important prerequisite for planning dog rabies vaccination campaigns.

Interplay between rabies virus and the mammalian immune system

Rabies is a disease caused following infection of the brain by the rabies virus (RABV). The principle mechanism of transmission is through a bite wound. The virus infects peripheral nerves and moves to the central nervous system (CNS). There appears to be little involvement of other organ systems and little detectable immune stimulation prior to infection of the CNS. This failure of the mammalian immune system to respond to rabies virus infection leads, in the overwhelming majority of cases, to death of the host. To some extent, this failure is likely due to the exclusive replication of RABV in neurons and the limited ability to generate, sufficiently rapidly, an anti-viral antibody response in situ. This is reflected in the ability of post-exposure vaccination, when given early after infection, to prevent disease. The lack of immune stimulation during RABV infection preceding neural invasion is the Achilles heel of the immune response. Whilst many viruses infect the brain, causing encephalitis and neuronal deficit, none are as consistently fatal to the host as RABV. This is in part due to prior replication of many viruses in peripheral, non-neural tissue by other viruses that allows timely activation of the immune response before the host is overwhelmed. Our current understanding of the correlates of protection for rabies suggests that it is the action of neutralising antibodies that prevent infection and control spread of RABV. Furthermore, it tells us that the induction of immunity can protect and understanding how and why this happens is critical to controlling infection. However, the paradigm of antibody development suggests that antigen presentation overwhelmingly occurs in lymphoid tissue (germinal and non-germinal centres) and these are external to the CNS. In addition, the blood-brain-barrier may provide a block to the delivery of immune effectors (antibodies/plasma B-cells) entering where they are needed. Alternatively, there may be insufficient antigen exposure after natural infection to mount an effective response or the virus actively suppresses immune function. To improve our ability to treat this fatal infection it is imperative to understand how immunity to RABV develops and functions so that parameters of protection are better defined.

Rabies: Rare Human Infection - Common Questions

Rabies is an acute, rapidly progressive encephalitis that is almost always fatal. Prophylaxis is highly effective but economics limits disease control. The mechanism of death from rabies is unclear. It is poorly cytopathic and poorly inflammatory. Rabies behaves like an acquired metabolic disorder. There may be a continuum of disease severity. History of animal bite is rare. The diagnosis is often missed. Intermittent encephalopathy, dysphagia, hydrophobia and aerophobia, and focal paresthesias or myoclonic jerks suggest rabies. Laboratory diagnosis is cumbersome but sensitive. Treatment is controversial but survivors are increasingly reported, with good outcomes in 4 of 8 survivors.

Infectious neuropathies

PURPOSE OF REVIEW

Infections are important, potentially treatable causes of peripheral nervous system disease. This article reviews the clinical presentation and management of several common peripheral nervous system diseases due to viral, bacterial, spirochetal, and parasitic infections.

RECENT FINDINGS

The clinical presentation and evaluation of infectious peripheral nervous system diseases are well established. Advances in the treatment and, in some cases, the prevention of these diseases are still evolving.

SUMMARY

A diverse range of peripheral nervous system diseases, including peripheral neuropathy, radiculopathy, radiculomyelopathy, cranial neuropathy, and motor neuropathy, are caused by numerous infectious agents. In some patients, peripheral neuropathy may be a side effect of anti-infectious drugs. Infectious neuropathies are important to recognize as they are potentially treatable. This article discusses the clinical presentation, evaluation, and treatment of several common peripheral nervous system diseases caused by viral, bacterial, spirochetal, and parasitic infections, as well as some peripheral nerve disorders caused by adverse effects of the treatments of these infectious diseases.

Vaccination in elite athletes

Public health vaccination guidelines cannot be easily transferred to elite athletes. An enhanced benefit from preventing even mild diseases is obvious but stronger interference from otherwise minor side effects has to be considered as well. Thus, special vaccination guidelines for adult elite athletes are required. In most of them, protection should be strived for against tetanus, diphtheria, pertussis, influenza, hepatitis A, hepatitis B, measles, mumps and varicella. When living or traveling to endemic areas, the athletes should be immune against tick-borne encephalitis, yellow fever, Japanese encephalitis, poliomyelitis, typhoid fever, and meningococcal disease. Vaccination against pneumococci and Haemophilus influenzae type b is only relevant in athletes with certain underlying disorders. Rubella and papillomavirus vaccination might be considered after an individual risk–benefit analysis. Other vaccinations such as cholera, rabies, herpes zoster, and Bacille Calmette–Guérin (BCG) cannot be universally recommended for athletes at present. Only for a very few diseases, a determination of antibody titers is reasonable to avoid unnecessary vaccinations or to control efficacy of an individual’s vaccination (especially for measles, mumps, rubella, varicella, hepatitis B and, partly, hepatitis A). Vaccinations should be scheduled in a way that possible side effects are least likely to occur in periods of competition. Typically, vaccinations are well tolerated by elite athletes, and resulting antibody titers are not different from the general population. Side effects might be reduced by an optimal selection of vaccines and an appropriate technique of administration. Very few discipline-specific considerations apply to an athlete’s vaccination schedule mainly from the competition and training pattern as well as from the typical geographical distribution of competitive sites.

Why we can prevent, control and possibly treat – but will not eradicate – rabies

ABSTRACT 

Rabies is an acute, progressive viral encephalitis. Despite historical recognition, millions still remain exposed annually. Most fatalities are of children, although this zoonosis is a vaccine-preventable disease. All developed countries interrupted canine transmission and increasingly, Asian and African communities recognize what Latin Americans demonstrated – dog rabies can be eliminated – by mass application of veterinary vaccines. Realistically, rabies is not a candidate for eradication. Management is lacking for major reservoirs, such as bats. Increasing pre-exposure immunization of individuals at risk, simplification of postexposure schedules, enhancing vaccine delivery by alternative routes, development of less expensive biologics and antiviral drugs, may lessen its impact if applied strategically in a One Health context.

Cost-effectiveness of rabies post-exposure prophylaxis in the context of very low rabies risk: A decision-tree model based on the experience of France

INTRODUCTION

Benefit-risk of different anti-rabies post-exposure prophylaxis (PEP) strategies after scratches or bites from dogs with unknown rabies status is unknown in very low rabies risk settings.

DESIGN AND SETTING

A cost-effectiveness analysis in metropolitan France using a decision-tree model and input data from 2001 to 2011.

POPULATION

A cohort of 2807 patients, based on the mean annual number of patients exposed to category CII (minor scratches) or CIII (transdermal bite) dog attacks in metropolitan France between 2001 and 2011.

INTERVENTIONS

Five PEP strategies: (A) no PEP for CII and CIII; (B) vaccine only for CIII; (C) vaccine for CII and CIII; (D) vaccine+ rabies immunoglobulin (RIG) only for CIII; and (E) vaccine for CII and vaccine+ RIG for CIII.

MAIN OUTCOMES MEASURES

The number of deaths related to rabies and to traffic accidents on the way to anti-rabies centers (ARC), effectiveness in terms of years of life gained by reducing rabies cases and avoiding traffic accidents, costs, and incremental cost-effectiveness ratios (ICER) associated with each strategy.

RESULTS

Strategy E led to the fewest rabies cases (3.6 × 10(-8)) and the highest costs (€ 1,606,000) but also to 1.7 × 10(-3) lethal traffic accidents. Strategy A was associated with the most rabies cases (4.8 × 10(-6)), but the risk of traffic accidents and costs were null; therefore, strategy A was the most effective and the least costly. The sensitivity analysis showed that, when the probability that a given dog is rabid a given day (PA) was > 1.4 × 10(-6), strategy D was more effective than strategy A; strategy B became cost-effective (i.e. ICER vs strategy A < 3 × French Gross Domestic Product per capita) when PA was > 1 .4 × 10(-4).

CONCLUSIONS

In the metropolitan France's very low rabies prevalence context, PEP with rabies vaccine, administered alone or with RIG, is associated with significant and unnecessary costs and unfavourable benefit-risk ratios regardless to exposure category.