Rabies post-exposure prophylaxis: A systematic review on abridged vaccination schedules and the effect of changing administration routes during a single course

Study of the effectiveness of combined rabies-tetanus vaccine as compared to individual vaccines

Purpose

Effective treatment for animal bites is essential, encompassing immediate measures and protocols for rabies and tetanus vaccination. In this study, we evaluated the effectiveness of the administration of individual and combined rabies-tetanus (RT) vaccines in mice as model animals.

Materials and Methods

Animal groups were injected with either undiluted Toxovac® combined with Rabies vaccine® (RT/Group 1)/Speeda® (ST/Group 3), 2-fold diluted Toxovac® with Rabies vaccine® (RT1/2/Group 2), or purified tetanus toxoid with Speeda® (Spurf/Group 4). Mice were immunized with either 2 intraperitoneal (IP) doses at one-week interval or one subcutaneous (SC) dose for rabies immunogenicity, and with one SC dose for tetanus immunogenicity. The potency of the vaccines was determined through challenge test, while their immunogenicity was examined by measuring the anti-rabies and anti-tetanus immunoglobulin G response.

Results

All tested vaccines were potent except Spurf; tetanus was not potent. Rabies' immunogenicity for all combinations through both routes of administration showed comparable antibody response & non-significant difference (p≥0.05) at days 14 and 28 compared to single rabies injected by 2 IP doses. Tetanus' immunogenicity in combinations was compared with Toxovac®. RT depicted higher antibody response on both days 14 and 28. Whereas RT1/2 showed a non-significant difference on both days 14 and 28. Therefore, rabies has a synergistic effect on tetanus in combination.

Conclusion

The immune response to rabies in combination vaccine injected as a single SC dose was as effective as 2 IP doses of single vaccine. Our results highlight the potential of RT combination vaccine via SC as a cost-effective means to provide protective immunity.

Metal-Phenolic Network Hydrogel Vaccine Platform for Enhanced Humoral Immunity against Lethal Rabies Virus

Rabies, caused by rabies virus (RABV), is a zoonotic disease with a high mortality rate that has attracted global attention with the goal of eradication by 2030. However, rabies can only be prevented by appropriate and multiple vaccinations, which impede widespread vaccination in developing countries due to its high expenditure. Designing single-dose vaccines is a pressing challenge in the prevention of rabies and other infectious diseases. Herein, a metal-phenolic network (MPN)-based hydrogel vaccine (designated as CGMR) was developed to stimulate potent humoral immunity against RABV infection by a single immunization, resulting in 4.3-fold and 1.8-fold enhancements of virus-neutralizing antibody compared with that induced by inactivated RABV and alum adjuvant. The CGMR, cross-linked by phenol-modified chitosan with manganese ion, could prolong residence time by confining the antigen to the network of hydrogel, acting as a "hydrogel antigen depot". It also stimulated the activation of the cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS)-stimulator of interferon gene (STING) pathway, facilitating dendritic cell maturation and antigen presentation. The vaccine formulation recruited immunocytes and activated the germinal center, enhancing and sustaining humoral immune responses against the virulent RABV challenge. Collectively, this injectable manganese-based hydrogel vaccine provides a universal and ideal avenue for rabies and other infectious diseases.

Rabies post-exposure prophylaxis delivery to ensure treatment efficacy and increase compliance

Objectives

Since rabies is lethal once symptoms appear, its prevention including community awareness, mass dog vaccination and post-exposure prophylaxis (PEP) is crucial. Although safe and potent rabies vaccines have long been available, the global rabies burden is still high and access to adequately-delivered PEP remains challenging. Here we offer healthcare providers up-to-date, simple, exhaustive, visual guidance on how to perform PEP steps correctly.

Protocol

PEP consists of 1) washing the wound with water and soap for 15 min, 2) assessing the need for rabies biologicals based on specific criteria; 3) administering, if required, rabies immunoglobulin or monoclonal antibodies deep in and around all wounds; 4) starting, if necessary, the WHO-recommended intradermal 1-week vaccination regimen; 5) informing patients adequately throughout the PEP process to increase compliance and avoid dangerous misconceptions about animal bite treatment and rabies risk.

Discussion

The intradermal 1-week vaccination regimen recommended by WHO is as safe as other regimens but carries important cost-, dose- and time-sparing benefits. As fundamental as the correct administration of rabies biologicals is clear doctor-patient communication and sharing of up-to-date knowledge among healthcare professionals.

Conclusions

This resource will help ensuring that no life is lost to rabies, an incurable yet preventable disease.

Comparing the genetic typing methods for effective surveillance and rabies control in Georgia

A full nucleoprotein gene sequencing of 68 isolates collected from passive rabies surveillance system in Georgia between 2015 and 2016 identified two distinct dog rabies phylogroups, GEO_V1 and GEO_V2, which both belonged to the cosmopolitan dog clade. GEO_V1 was found throughout the country and was further divided into four sub-phylogroups that overlapped geographically; GEO_V2 was found in the southeast region and was closely related to dog rabies in Azerbaijan. A sequence analysis of the full N gene, partial nucleoprotein gene of N-terminal and C-terminal, and the amplicon sequences of pan-lyssavirus RT-qPCR LN34 showed that all four sequencing approaches provided clear genetic typing results of canine rabies and could further differentiate GEO_V1 and GEO_V2. The phylogenetic analysis results vary and were affected by the length of the sequences used. Amplicon sequencing of the LN34 assay positive samples provided a rapid and cost-effective method for rabies genetic typing, which is important for improving rabies surveillance and canine rabies eradication globally.

Epidemiologic Aspects of Animal Bite, Rabies, and Predictors of Delay in Post-exposure Prophylaxis: A National Registry-based Study in Iran

BACKGROUND

The increasing trend in animal bites and rabies in recent years makes the disease a public health concern in Iran. The objectives of the current study were to investigate the epidemiologic aspects of the animal bite and determine the associated risk factors of the delay in initiation of post-exposure prophylaxis (PEP) against rabies in Iran.

STUDY DESIGN

National registry-based cross-sectional study.

METHODS

This study included all registered cases of animal bites between March 2021 and March 2022 at the Ministry of Health and Medical Education in Iran. We retrieved epidemiologic data on person, time, place, and PEP outcome.

RESULTS

A total of 260470 animal bite cases (approximately 334 per 100000 populations, and 11 deaths) were registered during the study period. About 77.2% of them were reported in males, 4.3% in children aged less than 5 years, 56.4% occurred in urban areas, 98% in domestic animals, and mostly in north and northeast areas of Iran. Additionally, 2.8% of cases had a delay of more than 48 hours in the initiation of PEP. Significant determinants of the increase in delay were female gender (OR=1.43, 95% CI: 1.36, 1.51, P<0.001), foreign nationality (OR=1.19, 95% CI: 1.01, 1.12, P=0.001), rural residence (OR=1.07, 95% CI: 1.01, 1.12, P=0.010), and the wild animals (OR=1.22, 95% CI: 1.12, 1.34, P<0.001).

CONCLUSION

The observed frequency of animal bites in a year indicates a serious public health concern and the need for targeted interventions, especially in at-risk areas and vulnerable populations.

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.

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.

Postexposure-vaccine-prophylaxis against COVID-19

During the COVID-19 pandemic, postexposure-vaccine-prophylaxis is not a practice. Following exposure, only patient isolation is imposed. Moreover, no therapeutic prevention approach is applied. We asked whether evidence exists for reduced mortality rate following postexposure-vaccine-prophylaxis. To estimate the effectiveness of postexposure-vaccine-prophylaxis, we obtained data from the Israeli Ministry of Health registry. The study population consisted of Israeli residents aged 12 years and older, identified for the first time as PCR-positive for SARS-CoV-2, between December 20th, 2020 (the beginning of the vaccination campaign) and October 7th, 2021. We compared "recently injected" patients-that proved PCR-positive on the same day or on 1 of the 5 consecutive days after first vaccination (representing an unintended postexposure-vaccine-prophylaxis)s-to unvaccinated control group. Among Israeli residents identified PCR-positive for SARS-CoV-2, 11 687 were found positive on the day they received their first vaccine injection (BNT162b2) or on 1 of the 5 days thereafter. In patients over 65 years, 143 deaths occurred among 1412 recently injected (10.13%) compared to 255 deaths among the 1412 unvaccinated (18.06%), odd ratio (OR) 0.51 (95% confidence interval [CI]: 0.41-0.64; p < 0.001). A significant reduction in the death toll was observed among the 55-64 age group, with 8 deaths occurring among the 1320 recently injected (0.61%) compared to 24 deaths among the 1320 unvaccinated control (1.82%), OR 0.33 (95% CI: 0.13-0.76; p = 0.007). Postexposure-vaccine-prophylaxis is effective against death in COVID-19 infection.

Natural-Product-Based Solutions for Tropical Infectious Diseases

About half of the world's population and 80% of the world's biodiversity can be found in the tropics. Many diseases are specific to the tropics, with at least 41 diseases caused by endemic bacteria, viruses, parasites, and fungi. Such diseases are of increasing concern, as the geographic range of tropical diseases is expanding due to climate change, urbanization, change in agricultural practices, deforestation, and loss of biodiversity. While traditional medicines have been used for centuries in the treatment of tropical diseases, the active natural compounds within these medicines remain largely unknown. In this review, we describe infectious diseases specific to the tropics, including their causative pathogens, modes of transmission, recent major outbreaks, and geographic locations. We further review current treatments for these tropical diseases, carefully consider the biodiscovery potential of the tropical biome, and discuss a range of technologies being used for drug development from natural resources. We provide a list of natural products with antimicrobial activity, detailing the source organisms and their effectiveness as treatment. We discuss how technological advancements, such as next-generation sequencing, are driving high-throughput natural product screening pipelines to identify compounds with therapeutic properties. This review demonstrates the impact natural products from the vast tropical biome have in the treatment of tropical infectious diseases and how high-throughput technical capacity will accelerate this discovery process.

Functionalized Nanoparticles in Prevention and Targeted Therapy of Viral Diseases With Neurotropism Properties, Special Insight on COVID-19

Neurotropic viruses have neural-invasive and neurovirulent properties to damage the central nervous system (CNS), leading to humans' fatal symptoms. Neurotropic viruses comprise a lot of viruses, such as Zika virus (ZIKV), herpes simplex virus (HSV), rabies virus (RABV), and severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2). Effective therapy is needed to prevent infection by these viruses in vivo and in vitro. However, the blood-brain barrier (BBB) usually prevents macromolecules from entering the CNS, which challenges the usage of the traditional probes, antiviral drugs, or neutralizing antibodies in the CNS. Functionalized nanoparticles (NPs) have been increasingly reported in the targeted therapy of neurotropic viruses due to their sensitivity and targeting characteristics. Therefore, the present review outlines efficient functionalized NPs to further understand the recent trends, challenges, and prospects of these materials.

Safety and Immunogenicity of a novel three-dose recombinant nanoparticle rabies G protein vaccine administered as simulated post exposure immunization: A randomized, comparator controlled, multicenter, phase III clinical study

BACKGROUND

Rabies vaccines are lifesaving in human post animal exposure. However, the compliance to the complete course of vaccine is found to be only 60%. Hence, there is a need for safe and immunogenic, shorter course vaccine that can enhance the compliance and effectively prevent the disease.

OBJECTIVES

To establish a noninferiority of a novel three-dose recombinant rabies G protein vaccine to be administered as simulated postexposure prophylaxis when compared to five-dose WHO prequalified vaccine for better safety and immunogenicity.

METHODS

A multi-centric, open label, assessor blind, center-specific block randomized, parallel design, phase III clinical study was conducted among 800 subjects. The eligible subjects were randomized in 2:1 ratio for recombinant rabies G protein vaccine and the reference vaccine. Subjects in recombinant rabies G protein vaccine arm received three doses of vaccine on days 0, 3, and 7, while subjects in reference vaccine arm received five doses of WHO prequalified vaccine on days 0, 3, 7, 14, and 28.

RESULTS

The socio-demographic characteristics of the two arms were comparable. About 9.9% subjects in recombinant rabies G protein vaccine arm and 17.2% subjects in reference arm reported adverse events. The sero-protection on day 14 was found to be 99.24% and 97.72% in recombinant rabies G protein vaccine arm and reference vaccine arm respectively and the difference was statistically nonsignificant.

CONCLUSION

The novel three-dose recombinant rabies G protein vaccine administered as simulated postexposure prophylaxis was noninferior to five dose WHO prequalified vaccine in terms of safety and immunogenicity.

Cellular responses at the application site of a high-density microarray patch delivering an influenza vaccine in a randomized, controlled phase I clinical trial

Microarray patches (MAPs) have the potential to be a safer, more acceptable, easier to use and more cost-effective method for administration of vaccines when compared to the needle and syringe. Since MAPs deliver vaccine to the dermis and epidermis, a degree of local immune response at the site of application is expected. In a phase 1 clinical trial (ACTRN 12618000112268), the Vaxxas high-density MAP (HD-MAP) was used to deliver a monovalent, split inactivated influenza virus vaccine into the skin. HD-MAP immunisation led to significantly enhanced humoral responses on day 8, 22 and 61 compared with IM injection of a quadrivalent commercial seasonal influenza vaccine (Afluria Quadrivalent®). Here, the aim was to analyse cellular responses to HD-MAPs in the skin of trial subjects, using flow cytometry and immunohistochemistry. HD-MAPs were coated with a split inactivated influenza virus vaccine (A/Singapore/GP1908/2015 [H1N1]), to deliver 5 μg haemagglutinin (HA) per HD-MAP. Three HD-MAPs were applied to the volar forearm (FA) of five healthy volunteers (to achieve the required 15 μg HA dose), whilst five control subjects received three uncoated HD-MAPs (placebo). Local skin response was recorded for over 61 days and haemagglutination inhibition antibody titres (HAI) were assessed on days 1, 4, 8, 22, and 61. Skin biopsies were taken before (day 1), and three days after HD-MAP application (day 4) and analysed by flow-cytometry and immunohistochemistry to compare local immune subset infiltration. HD-MAP vaccination with 15 μg HA resulted in significant HAI antibody titres compared to the placebo group. Application of uncoated placebo HD-MAPs resulted in mild erythema and oedema in most subjects, that resolved by day 4 in 80% of subjects. Active, HA-coated HD-MAP application resulted in stronger erythema responses on day 4, which resolved between days 22-61. Overall, these erythema responses were accompanied by an influx of immune cells in all subjects. Increased cell infiltration of CD3+, CD4+, CD8+ T cells as well as myeloid CD11b+ CD11c+ and non-myeloid CD11b- dendritic cells were observed in all subjects, but more pronounced in active HD-MAP groups. In contrast, CD19+/CD20+ B cell counts remained unchanged. Key limitations include the use of an influenza vaccine, to which the subjects may have had previous exposure. Different results might have been obtained with HD-MAPs inducing a primary immune response. In conclusion, influenza vaccine administered to the forearm (FA) using the HD-MAP was well-tolerated and induced a mild to moderate skin response with lymphocytic infiltrate at the site of application.

A shorter post-exposure prophylaxis regimen for rabies, Pakistan

OBJECTIVE

To assess the cost and effectiveness of the two-site, 1-week, intradermal rabies post-exposure prophylaxis regimen recommended by the World Health Organization (WHO) in 2018.

METHODS

We compared the number of rabies vaccine and rabies immunoglobulin ampoules consumed at The Indus Hospital in Karachi, Pakistan and their cost before and after implementing WHO's 2018 recommendations. In 2017, patients with suspected rabies-infected bites were treated using the two-site, 4-week, Thai Red Cross regimen, which involved administering four rabies vaccine doses intradermally over 4 weeks and infiltrating immunoglobulin into serious wounds, with the remainder injected into a distant muscle. In 2018, patients received three vaccine doses intradermally over 1 week, with a calculated amount of immunoglobulin infiltrated into wounds only. Remaining immunoglobulin was saved for other patients. The survival of patients bitten by apparently rabid dogs was used as a surrogate for effectiveness.

FINDINGS

Despite treating 8.5% more patients in 2018 (5370 patients) than 2017 (4948 patients), 140 fewer ampoules of rabies vaccine and 436 fewer ampoules of rabies immunoglobulin were used, at a cost saving of 4202 United States dollars. Of 56 patients bitten by apparently rabid dogs, 50 were alive at 6-month follow-up. The remaining six patients could not be contacted but did not present to any hospital with rabies.

CONCLUSION

The new regimen was more economical than the two-site, 4-week regimen and was equally effective. This regimen is recommended for preventing rabies in countries where the disease is endemic and rabies vaccine and immunoglobulin are in short supply.

Rabies encephalitis in a preschool child following postexposure prophylaxis

We report a case of rabies encephalitis in a 4½-year-old male child with an exposure to a suspect rabid dog. The child developed rabies 25 days after receiving postexposure prophylaxis. Rabies immunoglobulin (RIG) is currently administered according to body weight. In high-risk exposures over the head and neck, local administration of RIG over and above the body weight depending on the site, size, and severity of exposure may help to prevent rabies death. There is a need for further studies to generate new evidence in this regard.

Immunogenicity after pre- and post-exposure rabies vaccination: A systematic review and dose-response meta-analysis

BACKGROUND

There are a myriad of vaccine schedules for rabies pre- (PrEP) and post-exposure prophylaxis (PEP) that differ in the number and timedoses, number of visits, length of schedule, and route of administration. The objective of this study was to systematically review the evidence and investigate how thedifferences in schedules influence titres over time.

METHODS

Four databaseswere searched from inception to January 2020 for rabies PrEP and PEP studies. Adose-response meta-analysis was utilised to pool geometric mean titres (GMT) over time. Subgroup analyses by route of administration, age group, and schedule were conducted.

RESULTS

80 studies met the inclusion criteria and contributed with 191 datasets and 12,413 participants. Both intradermal (ID) and intramuscular (IM) PrEP/PEP produce adequate GMTs. Significantly lower GMT levels were achieved in older (>50yrs) compared to younger (<50yrs) participants. Short 1-week schedules were as effective as longer schedules that can take between 3 and 12 weeks to complete.

CONCLUSIONS

Several effective ID and IM schedules were identified, the selection of a schedule should take into account the patient's needs, costs, availability to return for subsequent doses, and the time required to complete the schedule. Older individuals warrant special attention as they develop lower antibody response.

Lean Management Promotes Compliance and Satisfaction of Rabies Vaccines

OBJECTIVE

This study aimed to explore the application effect of lean management in rabies vaccination.

METHODS

Lean management in rabies vaccination was implemented from July 2020. A total of 2306 patients vaccinated from January to June 2020 were enrolled as routine management group, and 2718 patients vaccinated from July to November 2020 were enrolled as lean management group. The relationship between potential factors and rabies vaccination with 1:1 propensity score matching (PSM) was analysed. The compliance, waiting time for vaccination, and satisfaction of patients of routine and lean management group were statistically analyzed. The changes in the three indicators before and after the implementation and their application effects were compared.

RESULTS

Compliance rate in lean management group (98.72%) was significantly higher than that in routine management group (93.87%) (χ ²=32.902, P<0.001). The waiting time for vaccination was also significantly shortened (t = 9.209, P < 0.001), and the satisfaction of patients significantly improved (X ² = 39.611, P < 0.001).

CONCLUSION

Implementing lean management in all aspects of rabies vaccination can significantly improve patient compliance and work efficiency of nursing staff and improve the patient medical experience.

Anno 2021: Which antivirals for the coming decade?

Despite considerable progress in the development of antiviral drugs, among which anti-immunodeficiency virus (HIV) and anti-hepatitis C virus (HCV) medications can be considered real success stories, many viral infections remain without an effective treatment. This not only applies to infectious outbreaks caused by zoonotic viruses that have recently spilled over into humans such as severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), but also ancient viral diseases that have been brought under control by vaccination such as variola (smallpox), poliomyelitis, measles, and rabies. A largely unsolved problem are endemic respiratory infections due to influenza, respiratory syncytial virus (RSV), and rhinoviruses, whose associated morbidity will likely worsen with increasing air pollution. Furthermore, climate changes will expose industrialized countries to a dangerous resurgence of viral hemorrhagic fevers, which might also become global infections. Herein, we summarize the recent progress that has been made in the search for new antivirals against these different threats that the world population will need to confront with increasing frequency in the next decade.

[New aspects of rabies control]

Rabies still causes about 60,000 human deaths per year, mainly in poor populations in Africa and Asia. However, since Louis Pasteur developed the first vaccine 130 years ago, prophylactic measures have been considerably improved and simplified. They now consist of the vaccine combined with purified rabies immunoglobulins of equine or human origin. In general, however, post-exposure prophylaxis protocols are long and expensive. Furthermore, the immunoglobulins used for associated serotherapy are costly and not widely available in developing countries. Approaches have been developed to deal with these two issues that offer hope for a paradigm shift for the benefit of exposed populations. Finally, mass rabies vaccination in dogs, which are the most cost-effective measure for preventing rabies in humans, are difficult to implement and sometimes have moderate effectiveness. The identification and analysis of the epidemiological drivers conditioning the circulation of the virus in dog populations allow a better understanding of the key control points that need to be associated with these campaigns for a better efficacy.

Neuroglia infection by rabies virus after anterograde virus spread in peripheral neurons

The highly neurotropic rabies virus (RABV) enters peripheral neurons at axon termini and requires long distance axonal transport and trans-synaptic spread between neurons for the infection of the central nervous system (CNS). Recent 3D imaging of field RABV-infected brains revealed a remarkably high proportion of infected astroglia, indicating that highly virulent field viruses are able to suppress astrocyte-mediated innate immune responses and virus elimination pathways. While fundamental for CNS invasion, in vivo field RABV spread and tropism in peripheral tissues is understudied. Here, we used three-dimensional light sheet and confocal laser scanning microscopy to investigate the in vivo distribution patterns of a field RABV clone in cleared high-volume tissue samples after infection via a natural (intramuscular; hind leg) and an artificial (intracranial) inoculation route. Immunostaining of virus and host markers provided a comprehensive overview of RABV infection in the CNS and peripheral nerves after centripetal and centrifugal virus spread. Importantly, we identified non-neuronal, axon-ensheathing neuroglia (Schwann cells, SCs) in peripheral nerves of the hind leg and facial regions as a target cell population of field RABV. This suggests that virus release from axons and infected SCs is part of the RABV in vivo cycle and may affect RABV-related demyelination of peripheral neurons and local innate immune responses. Detection of RABV in axon-surrounding myelinating SCs after i.c. infection further provided evidence for anterograde spread of RABV, highlighting that RABV axonal transport and spread of infectious virus in peripheral nerves is not exclusively retrograde. Our data support a new model in which, comparable to CNS neuroglia, SC infection in peripheral nerves suppresses glia-mediated innate immunity and delays antiviral host responses required for successful transport from the peripheral infection sites to the brain.

Tollwutprophylaxe: So beraten Sie in der Hausarztpraxis

Auch wenn von Reisen während der COVID-19-Pandemie gegenwärtig noch weitgehend abzusehen ist, bleibt Tollwut ein wichtiges Thema, dem Sie sich spätestens dann wieder widmen müssen, wenn die ersten Kurzentschlossenen zur Reiseberatung in Ihrer Praxis erscheinen werden. Dieser Beitrag frischt Ihr vorhandenes Wissen auf und informiert Sie insbesondere über das von der WHO propagierte verkürzte präexpositionelle Impfschema.

Health economic assessment of a rabies pre-exposure prophylaxis program compared with post-exposure prophylaxis alone in high-risk age groups in the Philippines

OBJECTIVES

Once symptoms appear, rabies is almost always fatal and accounts for 200-300 deaths annually in the Philippines. Available rabies vaccines can be administered either in pre- exposure prophylaxis (PrEP) or post-exposure prophylaxis (PEP). After exposure, PrEP-immunized individuals require fewer doses of PEP and no rabies immunoglobulin.

METHODS

A static decision-tree model was developed to assess cost-effectiveness of a PrEP+PEP program vs PEP alone. Philippines-specific data for people seeking medical advice at the Research Institute for Tropical Medicine between July 2015 and June 2016 were used in the model, together with data from published literature.

RESULTS

Over a 20-year period, in a cohort of 1 million 5-year-old children in the Philippines, PrEP+PEP was expected to prevent 297 deaths compared with PEP alone. From both payer and societal perspectives, the resulting incremental cost-effectiveness ratios were 36 035 (US$759; 2016 US$ conversion) and 18 663 (US$393) Philippine Pesos (PHP) - quality-adjusted life-years gained - respectively, which are both below the willingness-to-pay threshold of PHP140 255 (US$2 953).

CONCLUSION

These data suggest that a universal PrEP program targeting 5-year-olds would be cost-effective in the Philippines.

Modern biologics for rabies prophylaxis and the elimination of human cases mediated by dogs

Introduction: Rabies is a major viral zoonosis and neglected tropical disease, with a global distribution. Humans, domestic animals, and wild mammals are susceptible to infection. Etiological agents reside in the Order Mononegavirales, Family Rhabdoviridae, Genus Lyssavirus. This acute, progressive encephalitis causes the highest case fatality of any conventional infectious disease. Tens of millions of humans become exposed annually to the bites of infected mammals, predominantly in Asia and Africa. Despite the existence of effective vaccines and immune globulins, tens of thousands of people, typically children in the developing world, succumb. Areas covered: Concentrating upon both historical and major published references from the peer-reviewed literature over the past 5 years, we describe current biologics for rabies prevention, newly recommended principles for prophylaxis, and relevant future products in the developmental pipeline. Expert opinion: Modern human rabies biologics are pure, potent, safe, and efficacious, when used in a timely and appropriate manner. Few individuals survive after clinical signs. Anti-viral compounds are not licensed. Experimental therapy, while obviously desirable, is highly controversial. Education on bite prevention and integrated risk management are critical. Access to affordable care, dose-sparing, and shortened regimens of human rabies biologics remain key.

Purified Vero Cell Rabies Vaccine (PVRV, Verorab®): A Systematic Review of Intradermal Use Between 1985 and 2019

The purified Vero cell rabies vaccine (PVRV; Verorab®, Sanofi Pasteur) has been used in rabies prevention since 1985. Evolving rabies vaccination trends, including shorter intradermal (ID) regimens with reduced volume, along with WHO recommendation for ID administration has driven recent ID PVRV regimen assessments. Thus, a consolidated review comparing immunogenicity of PVRV ID regimens during pre-exposure prophylaxis (PrEP) and post-exposure prophylaxis (PEP) is timely and beneficial in identifying gaps in current research. A search of seven databases for studies published from 1985 to November 2019 identified 35 studies. PrEP was assessed in 10 studies (n = 926) with 1-3-site, 1-3-visit regimens of up to 3-months duration. Seroconversion (rabies virus neutralizing antibodies [RVNA] ≥ 0.5 IU/mL) rates of 90-100% were reported within weeks, irrespective of regimen, with robust booster responses at 1 year (100% seroconversion rates by day 14 post-booster). However, data are lacking for the current WHO-recommended, 2-site, 1-week ID PrEP regimen. PEP was assessed in 25 studies (n = 2136) across regimens of 1-week to 90-day duration. All ID PEP regimens assessed induced ≥ 99% seroconversion rates (except in HIV participants) by day 14-28. This review confirms ID PVRV suitability for rabies prophylaxis and highlights the heterogeneity of use in the field.

A 1-week intradermal dose-sparing regimen for rabies post-exposure prophylaxis (RESIST-2): an observational cohort study

BACKGROUND

The international health authorities are backing an effort to eliminate canine-mediated rabies in humans by 2030. This effort will require improving access to adequate and timely rabies post-exposure prophylaxis as compliance is low with WHO-recommended regimens (given in four to five visits over 1 month). Access could be substantially improved by an abridged regimen to reduce doses, direct and indirect costs, and improve vaccine equity by better sharing of available vaccine. We aimed to compare rabies virus neutralising antibody titres before and after the fourth visit to determine whether that session was needed or the current regimen could be abridged.

METHODS

In this observational cohort study, we measured rabies virus neutralising antibody titres using rapid fluorescent focus inhibition tests in 116 people bitten by dogs with laboratory-confirmed rabies and 20 control individuals. Percentages of circulating plasmablasts were determined by flow cytometry. All individuals had been referred to the rabies prevention clinic at Institut Pasteur in Cambodia and received two intradermal injections of post-exposure prophylaxis on days 0, 3, 7, and 28 (Thai Red Cross regimen) with or without equine rabies immunoglobulin, as per 2010 WHO recommendations.

FINDINGS

All individuals had rabies virus neutralising antibody titres considered protective (≥0·5 IU/mL) and plasmablast activation on day 28 before the last injection. The median rabies virus neutralising antibody concentration in the group of individuals bitten by rabies virus-positive dogs was 1·08 IU/mL (IQR 0·37-3·09) on day 7, 26·86 (22·68-49·50) on day 28, and 26·74 (11·78-49·06) on day 42. No significant differences were observed in titres between days 28 and 42, after titres reached a plateau. These titres were reached notwithstanding equine rabies immunoglobulin use, age, sex, nutrition status as indicated by upper-arm circumference in children or BMI in adults, or dog infection status. Titres or plasmablast percentages did not increase between the day of the last injection and 2 weeks later. All patients were alive 1 year after post-exposure prophylaxis.

INTERPRETATION

The fourth vaccine session on day 28 provides no additional benefit. Rabies post-exposure prophylaxis can be abridged to a two-dose, three-session, 1 week regimen to improve post-exposure prophylaxis coverage and equity at no risk to patients.

FUNDING

Institut Pasteur.