Last data update: Nov 04, 2024. (Total: 48056 publications since 2009)
Records 1-27 (of 27 Records) |
Query Trace: Smith TG[original query] |
---|
Notes from the field: Mpox cluster caused by tecovirimat-resistant monkeypox virus - Five States, October 2023-February 2024
Gigante CM , Takakuwa J , McGrath D , Kling C , Smith TG , Peng M , Wilkins K , Garrigues JM , Holly T , Barbian H , Kittner A , Haydel D , Ortega E , Richardson G , Hand J , Hacker JK , Espinosa A , Haw M , Kath C , Bielby M , Short K , Johnson K , De La Cruz N , Davidson W , Hughes C , Green NM , Baird N , Rao AK , Hutson CL . MMWR Morb Mortal Wkly Rep 2024 73 (40) 903-905 The antiviral drug tecovirimat* has been used extensively to treat U.S. mpox cases since the start of a global outbreak in 2022. Mutations in the mpox viral protein target (F13 or VP37) that occur during treatment can result in resistance to tecovirimat(†) (1,2). CDC and public health partners have conducted genetic surveillance of monkeypox virus (MPXV) for F13 mutations through sequencing and monitoring of public databases. MPXV F13 mutations associated with resistance have been reported since 2022, typically among severely immunocompromised mpox patients who required prolonged courses of tecovirimat (3-5). A majority of patients with infections caused by MPXV with resistant mutations had a history of tecovirimat treatment; however, spread of tecovirimat-resistant MPXV was reported in California during late 2022 to early 2023 among persons with no previous tecovirimat treatment (3). This report describes a second, unrelated cluster of tecovirimat-resistant MPXV among 18 persons with no previous history of tecovirimat treatment in multiple states. |
Tecovirimat resistance in Mpox patients, United States, 2022-2023
Smith TG , Gigante CM , Wynn NT , Matheny A , Davidson W , Yang Y , Condori RE , O'Connell K , Kovar L , Williams TL , Yu YC , Petersen BW , Baird N , Lowe D , Li Y , Satheshkumar PS , Hutson CL . Emerg Infect Dis 2023 29 (12) 2426-2432 During the 2022 multinational outbreak of monkeypox virus (MPXV) infection, the antiviral drug tecovirimat (TPOXX; SIGA Technologies, Inc., https://www.siga.com) was deployed in the United States on a large scale for the first time. The MPXV F13L gene homologue encodes the target of tecovirimat, and single amino acid changes in F13 are known to cause resistance to tecovirimat. Genomic sequencing identified 11 mutations previously reported to cause resistance, along with 13 novel mutations. Resistant phenotype was determined using a viral cytopathic effect assay. We tested 124 isolates from 68 patients; 96 isolates from 46 patients were found to have a resistant phenotype. Most resistant isolates were associated with severely immunocompromised mpox patients on multiple courses of tecovirimat treatment, whereas most isolates identified by routine surveillance of patients not treated with tecovirimat remained sensitive. The frequency of resistant viruses remains relatively low (<1%) compared with the total number of patients treated with tecovirimat. |
Community spread of a human monkeypox virus variant with a tecovirimat resistance-associated mutation
Garrigues JM , Hemarajata P , Espinosa A , Hacker JK , Wynn NT , Smith TG , Gigante CM , Davidson W , Vega J , Edmondson H , Karan A , Marutani AN , Kim M , Terashita D , Balter SE , Hutson CL , Green NM . Antimicrob Agents Chemother 2023 67 (11) e0097223 Tecovirimat, also known as TPOXX or ST-246, is a drug available for the treatment of mpox. Tecovirimat targets the conserved orthopoxvirus VP37 protein (also known as F13) required for extracellular virus particle generation (1, 2). Multiple VP37 mutations associated with tecovirimat resistance have been reported within the current global mpox outbreak in immunocompromised individuals with advanced HIV infection (3 – 5). In many of these cases, resistance mutation heterogeneity was observed following tecovirimat exposure, suggesting resistance emerged under selective pressure during treatment. | To monitor circulating monkeypox virus (MPXV) within California, a genomic surveillance network was established whereby clinical and commercial laboratories provided positive specimens for whole-genome sequencing using an amplicon-based protocol and subsequent analysis (6 – 9). Through this surveillance, 11 mpox cases were identified in southern California with the same tecovirimat resistance-associated mutation (Table 1): a three-nucleotide deletion in the vaccinia virus Copenhagen F13L gene homolog (OPG057) resulting in asparagine removed from position 267 in the VP37 protein (VP37:N267del) (5) (https://www.fda.gov/emergency-preparedness-and-response/mcm-issues/fda-mpox-response#therapeutics). VP37:N267del was the only tecovirimat resistance-associated mutation detected in identified specimens and had allele frequencies greater than 89% in all instances, suggesting infections may have occurred with predominantly mutant virus. Phenotypic testing in vitro (3 – 5) confirmed tecovirimat resistance in ten identified specimens with EC50 values ranging from 1.488 to 3.977 µM, corresponding to an 85- to 230-fold change compared to wild-type isolates. |
Resistance to anti-orthopoxviral drug tecovirimat (TPOXX) during the 2022 mpox outbreak in the US (preprint)
Smith TG , Gigante CM , Wynn NT , Matheny A , Davidson W , Yang Y , Condori RE , O'Connell K , Kovar L , Williams TL , Yu YC , Petersen BW , Baird N , Lowe D , Li Y , Satheshkumar PS , Hutson CL . medRxiv 2023 18 Background: During the 2022 multinational outbreak of monkeypox virus (MPXV) clade IIb, the antiviral drug tecovirimat (TPOXX) was deployed in the US on a large scale for the first time ever. The MPXV F13L gene homolog encodes the target of tecovirimat, and single amino acid changes in the F13 protein are known to cause resistance to tecovirimat in orthopoxviruses (OPXV). Method(s): Whole genome metagenomic sequencing and amplicon-based sequencing targeting the F13L gene was used to identify nine mutations previously reported to cause resistance in other OPXV along with ten novel mutations that have been identified from the 2022 mpox outbreak. A cytopathic effect assay, previously established at CDC as part of WHO smallpox research, was adapted to MPXV for tecovirimat phenotype testing of virus isolated from mpox patients. Result(s): As of March 2023, in total, 70 isolates from 40 patients were tested, and 50 of these isolates from 26 patients were found to have a resistant phenotype. Most resistant isolates were associated with severely immunocompromised mpox patients on multiple courses of TPOXX treatment; while isolates with F13 mutations identified by routine surveillance of patients not treated with TPOXX have remained sensitive. Conclusion(s): These data indicate that tecovirimat resistance is developing in immunocompromised patients treated with TPOXX and that for isolates that we have analyzed, the frequency of resistant viruses remain relatively low (< 1%) compared to the total number of patients treated with TPOXX. These findings inform our understanding of when tecovirimat resistance is likely to occur and highlight the need for additional OPXV therapeutics. Copyright The copyright holder for this preprint is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. This article is a US Government work. It is not subject to copyright under 17 USC 105 and is also made available for use under a CC0 license. |
Identification of tecovirimat resistance-associated mutations in human monkeypox virus - Los Angeles County
Garrigues JM , Hemarajata P , Karan A , Shah NK , Alarcón J , Marutani AN , Finn L , Smith TG , Gigante CM , Davidson W , Wynn NT , Hutson CL , Kim M , Terashita D , Balter SE , Green NM . Antimicrob Agents Chemother 2023 67 (7) e0056823 Tecovirimat (also known as TPOXX or ST-246) is a drug available for the treatment of mpox through the Centers for Disease Control and Prevention’s Expanded Access Investigational New Drug “compassionate use” protocol (https://www.cdc.gov/poxvirus/monkeypox/clinicians/Tecovirimat.html). In Los Angeles County, a fatal case of mpox with tecovirimat resistance was previously reported (1). Epidemiologic surveillance in Los Angeles County has since identified additional cases of severe mpox that did not improve after multiple rounds of tecovirimat treatment, including one involving a person who succumbed to infection (Table 1). Consistent with reports describing severe manifestations of mpox within the current global outbreak (1, 2), the identified cases involved host immunodeficiency due to advanced HIV infection. |
Serological responses to the MVA-based JYNNEOS monkeypox vaccine in a cohort of participants from the Democratic Republic of Congo
Priyamvada L , Carson WC , Ortega E , Navarra T , Tran S , Smith TG , Pukuta E , Muyamuna E , Kabamba J , Nguete BU , Likafi T , Kokola G , Lushima RS , Tamfum JM , Okitolonda EW , Kaba DK , Monroe BP , McCollum AM , Petersen BW , Satheshkumar PS , Townsend MB . Vaccine 2022 40 (50) 7321-7327 The current worldwide monkepox outbreak has reaffirmed the continued threat monkeypox virus (MPXV) poses to public health. JYNNEOS, a Modified Vaccinia Ankara (MVA)-based live, non-replicating vaccine, was recently approved for monkeypox prevention for adults at high risk of MPXV infection in the United States. Although the safety and immunogenicity of JYNNEOS have been examined previously, the clinical cohorts studied largely derive from regions where MPXV does not typically circulate. In this study, we assess the quality and longevity of serological responses to two doses of JYNNEOS vaccine in a large cohort of healthcare workers from the Democratic Republic of Congo (DRC). We show that JYNNEOS elicits a strong orthopoxvirus (OPXV)-specific antibody response in participants that peaks around day 42, or 2 weeks after the second vaccine dose. Participants with no prior history of smallpox vaccination or exposure have lower baseline antibody levels, but experience a similar fold-rise in antibody titers by day 42 as those with a prior history of vaccination. Both previously naïve and vaccinated participants generate vaccinia virus and MPXV-neutralizing antibody in response to JYNNEOS vaccination. Finally, even though total OPXV-specific IgG titers and neutralizing antibody titers declined from their peak and returned close to baseline levels by the 2-year mark, most participants remain IgG seropositive at the 2-year timepoint. Taken together, our data demonstrates that JYNNEOS vaccination triggers potent OPXV neutralizing antibody responses in a cohort of healthcare workers in DRC, a monkeypox-endemic region. MPXV vaccination with JYNNEOS may help ameliorate the disease and economic burden associated with monkeypox and combat potential outbreaks in areas with active virus circulation. |
Multiple lineages of monkeypox virus detected in the United States, 2021-2022.
Gigante CM , Korber B , Seabolt MH , Wilkins K , Davidson W , Rao AK , Zhao H , Smith TG , Hughes CM , Minhaj F , Waltenburg MA , Theiler J , Smole S , Gallagher GR , Blythe D , Myers R , Schulte J , Stringer J , Lee P , Mendoza RM , Griffin-Thomas LA , Crain J , Murray J , Atkinson A , Gonzalez AH , Nash J , Batra D , Damon I , McQuiston J , Hutson CL , McCollum AM , Li Y . Science 2022 378 (6619) eadd4153 Monkeypox is a viral zoonotic disease endemic in Central and West Africa. In May 2022, dozens of non-endemic countries reported hundreds of monkeypox cases, most with no epidemiological link to Africa. We identified two lineages of monkeypox virus (MPXV) among two 2021 and seven 2022 U.S. monkeypox cases: the major 2022 outbreak variant, B.1, and a minor contemporaneously sampled variant called A.2. Analyses of mutations among these two variants revealed an extreme preference for GA-to-AA mutations indicative of human APOBEC3 cytosine deaminase activity among Clade IIb MPXV (previously West African, Nigeria) sampled since 2017. Such mutations were not enriched within other MPXV clades. These findings suggest that APOBEC3 editing may be a recurrent and a dominant driver of MPXV evolution within the current outbreak. |
A cocktail of human monoclonal antibodies broadly neutralizes North American rabies virus variants as a promising candidate for rabies post-exposure prophylaxis.
Ejemel M , Smith TG , Greenberg L , Carson WC , Lowe D , Yang Y , Jackson FR , Morgan CN , Martin BE , Kling C , Hutson CL , Gallardo-Romero N , Ellison JA , Moore S , Buzby A , Sullivan-Bolyai J , Klempner M , Wang Y . Sci Rep 2022 12 (1) 9403 Human rabies remains a globally significant public health problem. Replacement of polyclonal anti-rabies immunoglobulin (RIG), a passive component of rabies post-exposure prophylaxis (PEP), with a monoclonal antibody (MAb), would eliminate the cost and availability constraints associated with RIG. Our team has developed and licensed a human monoclonal antibody RAB1 (Rabishield()), as the replacement for RIG where canine rabies is enzootic. However, for the highly diverse rabies viruses of North America, a cocktail containing two or more MAbs targeting different antigenic sites of the rabies glycoprotein should be included to ensure neutralization of all variants of the virus. In this study, two MAb cocktails, R172 (RAB1-RAB2) and R173 (RAB1-CR57), were identified and evaluated against a broad range of rabies variants from North America. R173 was found to be the most potent cocktail, as it neutralized all the tested North American RABV isolates and demonstrated broad coverage of isolates from both terrestrial and bat species. R173 could be a promising candidate as an alternative or replacement for RIG PEP in North America. |
Negligible risk of rabies importation in dogs thirty days after demonstration of adequate serum antibody titer
Smith TG , Fooks AR , Moore SM , Freuling CM , Müller T , Torres G , Wallace RM . Vaccine 2021 39 (18) 2496-2499 Importation of one rabid dog from areas where rabies virus (RABV) is circulating into a country or zone that is declared free of rabies poses a threat of rabies re-introduction into the resident dog population (if “herd” immunity is insufficient) or congeneric species. To prevent rabies importation, the World Organisation for Animal Health (OIE) Terrestrial Code (8.14.7) currently recommends that rabies-vaccinated animals, individually identifiable and not showing any rabies clinical signs, have a minimum waiting period of three months between proof of adequate rabies serum antibody titer (≥ 0.5 IU/mL) and entry into a rabies free country. Alternatively, dogs may undergo a 6 month quarantine prior to import. The waiting period ensures that a dog with RABV neutralizing antibodies (rVNA) detected through OIE recommended methods is not incubating RABV, which can induce rVNA in late stages of disease. We propose reducing the waiting period to 30 days. |
Bat and Lyssavirus exposure among humans in area that celebrates bat festival, Nigeria, 2010 and 2013
Vora NM , Osinubi MOV , Davis L , Abdurrahman M , Adedire EB , Akpan H , Aman-Oloniyo AF , Audu SW , Blau D , Dankoli RS , Ehimiyein AM , Ellison JA , Gbadegesin YH , Greenberg L , Haberling D , Hutson C , Idris JM , Kia GSN , Lawal M , Matthias SY , Mshelbwala PP , Niezgoda M , Ogunkoya AB , Ogunniyi AO , Okara GC , Olugasa BO , Ossai OP , Oyemakinde A , Person MK , Rupprecht CE , Saliman OA , Sani M , Sanni-Adeniyi OA , Satheshkumar PS , Smith TG , Soleye MO , Wallace RM , Yennan SK , Recuenco S . Emerg Infect Dis 2020 26 (7) 1399-1408 Using questionnaires and serologic testing, we evaluated bat and lyssavirus exposure among persons in an area of Nigeria that celebrates a bat festival. Bats from festival caves underwent serologic testing for phylogroup II lyssaviruses (Lagos bat virus, Shimoni bat virus, Mokola virus). The enrolled households consisted of 2,112 persons, among whom 213 (10%) were reported to have ever had bat contact (having touched a bat, having been bitten by a bat, or having been scratched by a bat) and 52 (2%) to have ever been bitten by a bat. Of 203 participants with bat contact, 3 (1%) had received rabies vaccination. No participant had neutralizing antibodies to phylogroup II lyssaviruses, but >50% of bats had neutralizing antibodies to these lyssaviruses. Even though we found no evidence of phylogroup II lyssavirus exposure among humans, persons interacting with bats in the area could benefit from practicing bat-related health precautions. |
Lyssavirus Vaccine with a Chimeric Glycoprotein Protects across Phylogroups.
Fisher CR , Lowe DE , Smith TG , Yang Y , Hutson CL , Wirblich C , Cingolani G , Schnell MJ . Cell Rep 2020 32 (3) 107920 Rabies is nearly 100% lethal in the absence of treatment, killing an estimated 59,000 people annually. Vaccines and biologics are highly efficacious when administered properly. Sixteen rabies-related viruses (lyssaviruses) are similarly lethal, but some are divergent enough to evade protection from current vaccines and biologics, which are based only on the classical rabies virus (RABV). Here we present the development and characterization of LyssaVax, a vaccine featuring a structurally designed, functional chimeric glycoprotein (G) containing immunologically important domains from both RABV G and the highly divergent Mokola virus (MOKV) G. LyssaVax elicits high titers of antibodies specific to both RABV and MOKV Gs in mice. Immune sera also neutralize a range of wild-type lyssaviruses across the major phylogroups. LyssaVax-immunized mice are protected against challenge with recombinant RABV and MOKV. Altogether, LyssaVax demonstrates the utility of structural modeling in vaccine design and constitutes a broadened lyssavirus vaccine candidate. |
Antiviral ranpirnase TMR-001 inhibits rabies virus release and cell-to-cell infection in vitro
Smith TG , Jackson FR , Morgan CN , Carson WC , Martin BE , Gallardo-Romero N , Ellison JA , Greenberg L , Hodge T , Squiquera L , Sulley J , Olson VA , Hutson CL . Viruses 2020 12 (2) Currently, no rabies virus-specific antiviral drugs are available. Ranpirnase has strong antitumor and antiviral properties associated with its ribonuclease activity. TMR-001, a proprietary bulk drug substance solution of ranpirnase, was evaluated against rabies virus in three cell types: mouse neuroblastoma, BSR (baby hamster kidney cells), and bat primary fibroblast cells. When TMR-001 was added to cell monolayers 24 h preinfection, rabies virus release was inhibited for all cell types at three time points postinfection. TMR-001 treatment simultaneous with infection and 24 h postinfection effectively inhibited rabies virus release in the supernatant and cell-to-cell spread with 50% inhibitory concentrations of 0.2-2 nM and 20-600 nM, respectively. TMR-001 was administered at 0.1 mg/kg via intraperitoneal, intramuscular, or intravenous routes to Syrian hamsters beginning 24 h before a lethal rabies virus challenge and continuing once per day for up to 10 days. TMR-001 at this dose, formulation, and route of delivery did not prevent rabies virus transit from the periphery to the central nervous system in this model (n = 32). Further aspects of local controlled delivery of other active formulations or dose concentrations of TMR-001 or ribonuclease analogues should be investigated for this class of drugs as a rabies antiviral therapeutic. |
Inactivated rabies virus-based Ebola vaccine preserved by vaporization is heat-stable and immunogenic against Ebola and protects against rabies challenge
Kurup D , Fisher CR , Smith TG , Abreu-Mota T , Yang Y , Jackson FR , Gallardo-Romero N , Franka R , Bronshtein V , Schnell MJ . J Infect Dis 2019 220 (9) 1521-1528 BACKGROUND: Ebola virus (EBOV) is a highly lethal member of the Filoviridae family associated with human hemorrhagic disease. Despite being a sporadic disease, it caused a large outbreak in 2014-2016 in West Africa and another outbreak recently in the Democratic Republic of Congo. Several vaccine candidates are currently in preclinical and clinical studies but none are stable without cold chain storage. METHODS: We used preservation by vaporization (PBV), a novel processing technology to heat-stabilize FiloRab1 (inactivated rabies-based Ebola vaccine), a candidate Ebola vaccine, and stored the vials at temperatures ranging from 4 degrees C to 50 degrees C for 10 days to 12 months. We immunized Syrian hamsters with the best long-term stable FiloRab1 PBV vaccines and challenged them with rabies virus (RABV). RESULTS: Syrian hamsters immunized with FiloRab1 PBV-processed vaccines stored at temperatures of 4 degrees C and 37 degrees C for 6 months, and at 50 degrees C for 2 weeks, seroconverted against both RABV-G and EBOV-GP. Notably, all of the FiloRab1 PBV vaccines proved to be 100% effective in a RABV challenge model. CONCLUSIONS: We successfully demonstrated that the FiloRab1 PBV vaccines are stable and efficacious for up to 6 months when stored at temperatures ranging from 4 degrees C to 37 degrees C and for up to 2 weeks at 50 degrees C. |
Inactivated rabies virus-vectored immunocontraceptive vaccine in a thermo-responsive hydrogel induces high and persistent antibodies against rabies, but insufficient antibodies against gonadotropin-releasing hormone for contraception
Wu X , Yang Y , Kling C , Seigler L , Gallardo-Romero NF , Martin BE , Smith TG , Olson VA . Vaccines (Basel) 2019 7 (3) Rabies is preventable through vaccination, but the need to mount annual canine vaccination campaigns presents major challenges in rabies control and prevention. The development of a rabies vaccine that ensures lifelong immunity and animal population management in one dose could be extremely advantageous. A nonsurgical alternative to spay/neuter is a high priority for animal welfare, but irreversible infertility in one dose has not been achieved. Towards this goal, we developed a rabies virus-vectored immunocontraceptive vaccine ERA-2GnRH, which protected against rabies virus challenge and induced >80% infertility in mice after three doses in a live, liquid-vaccine formulation (Wu et al., 2014). To improve safety and use, we formulated an inactivated vaccine in a thermo-responsive chitosan hydrogel for one-dose delivery and studied the immune responses in mice. The hydrogel did not cause any injection site reactions, and the killed ERA-2GnRH vaccine induced high and persistent rabies virus neutralizing antibodies (rVNA) in mice. The rVNA in the hydrogel group reached an average of 327.40 IU/mL, more than 200 times higher than the liquid vaccine alone. The Gonadotropin-releasing hormone (GnRH) antibodies were also present and lasted longer in the hydrogel group, but did not prevent fertility in mice, reflecting a possible threshold level of GnRH antibodies for contraception. In conclusion, the hydrogel facilitated a high and long-lasting immunity, and ERA-2GnRH is a promising dual vaccine candidate. Future studies will focus on rabies protection in target species and improving the anti-GnRH response. |
Revisiting rabies virus neutralizing antibodies through infecting BALB/c mice with live rabies virus
Qin Y , Smith TG , Jackson F , Gallardo-Romero NF , Morgan CN , Olson V , Hutson CL , Wu X . Virus Res 2018 248 39-43 This study investigates the production of rabies virus (RABV) neutralizing antibody after virus infection through a mouse model. The BALB/c mice from different age groups (three, five, seven week old) were intramuscularly inoculated with live rabies virus (TX coyote 323R). Without pre-exposure or post-exposure prophylaxis (PEP), we found there is a decreased fatality with increased age of animals, the mortalities are 60%, 50%, and 30%, respectively. Interestingly, through assay of rapid fluorescent focus inhibition test (RFFIT), direct fluorescent antibody (DFA) and quantitative Polymerase Chain Reaction (qPCR), the results showed that all the animals that succumbed to rabies challenge, except one, developed circulating neutralizing antibodies, and all the healthy animals, except two, did not generate virus neutralizing antibodies (VNA). Our animal study suggests that the induction of VNA was an indicator of infection progression in the central nervous system (CNS) and speculate that RABV neutralizing antibodies did not cross the blood-brain barrier of the CNS for those diseased animals. We hypothesize that early release of viral antigens from damaged nerve tissue might potentially be a benefit for survivors, and we also discuss several other aspects of the interaction of RABV and its neutralizing antibodies. |
Potential confounding of diagnosis of rabies in patients with recent receipt of intravenous immune globulin
Vora NM , Orciari LA , Bertumen JB , Damon I , Ellison JA , Fowler VG Jr , Franka R , Petersen BW , Satheshkumar PS , Schexnayder SM , Smith TG , Wallace RM , Weinstein S , Williams C , Yager P , Niezgoda M . MMWR Morb Mortal Wkly Rep 2018 67 (5) 161-165 Rabies is an acute encephalitis that is nearly always fatal. It is caused by infection with viruses of the genus Lyssavirus, the most common of which is Rabies lyssavirus. The Council of State and Territorial Epidemiologists (CSTE) defines a confirmed human rabies case as an illness compatible with rabies that meets at least one of five different laboratory criteria.* Four of these criteria do not depend on the patient's rabies vaccination status; however, the remaining criterion, "identification of Lyssavirus-specific antibody (i.e. by indirect fluorescent antibody...test or complete [Rabies lyssavirus] neutralization at 1:5 dilution) in the serum," is only considered diagnostic in unvaccinated patients. Lyssavirus-specific antibodies include Rabies lyssavirus-specific binding immunoglobulin G (IgG) and immunoglobulin M (IgM) antibodies and Rabies lyssavirus neutralizing antibodies (RLNAs). This report describes six patients who were tested for rabies by CDC and who met CSTE criteria for confirmed human rabies because they had illnesses compatible with rabies, had not been vaccinated for rabies, and were found to have serum RLNAs (with complete Rabies lyssavirus neutralization at a serum dilution of 1:5). An additional four patients are described who were tested for rabies by CDC who were found to have serum RLNAs (with incomplete Rabies lyssavirus neutralization at a serum dilution of 1:5) despite having not been vaccinated for rabies. None of these 10 patients received a rabies diagnosis; rather, they were considered to have been passively immunized against rabies through recent receipt of intravenous immune globulin (IVIG). Serum RLNA test results should be interpreted with caution in patients who have not been vaccinated against rabies but who have recently received IVIG. |
In Vivo Efficacy of a Cocktail of Human Monoclonal Antibodies (CL184) Against Diverse North American Bat Rabies Virus Variants
Franka R , Carson WC , Ellison JA , Taylor ST , Smith TG , Kuzmina NA , Kuzmin IV , Marissen WE , Rupprecht CE . Trop Med Infect Dis 2017 2 (3) Following rabies virus (RABV) exposure, a combination of thorough wound washing, multiple-dose vaccine administration and the local infiltration of rabies immune globulin (RIG) are essential components of modern post-exposure prophylaxis (PEP). Although modern cell-culture-based rabies vaccines are increasingly used in many countries, RIG is much less available. The prohibitive cost of polyclonal serum RIG products has prompted a search for alternatives and design of anti-RABV monoclonal antibodies (MAbs) that can be manufactured on a large scale with a consistent potency and lower production costs. Robust in vitro neutralization activity has been demonstrated for the CL184 MAb cocktail, a 1:1 protein mixture of two human anti-RABV MAbs (CR57/CR4098), against a large panel of RABV isolates. In this study, we used a hamster model to evaluate the efficacy of experimental PEP against a lethal challenge. Various doses of CL184 and commercial rabies vaccine were assessed for the ability to protect against lethal infection with representatives of four distinct bat RABV lineages of public health relevance: silver-haired bat (Ln RABV); western canyon bat (Ph RABV); big brown bat (Ef-w1 RABV) and Mexican free-tailed bat RABV (Tb RABV). 42⁻100% of animals survived bat RABV infection when CL184 (in combination with the vaccine) was administered. A dose-response relationship was observed with decreasing doses of CL184 resulting in increasing mortality. Importantly, CL184 was highly effective in neutralizing and clearing Ph RABV in vivo, even though CR4098 does not neutralize this virus in vitro. By comparison, 19⁻95% survivorship was observed if human RIG (20 IU/kg) and vaccine were used following challenge with different bat viruses. Based on our results, CL184 represents an efficacious alternative for RIG. Both large-scale and lower cost production could ensure better availability and affordability of this critical life-saving biologic in rabies enzootic countries and as such, significantly contribute to the reduction of human rabies deaths globally. |
Evaluation of immune responses in dogs to oral rabies vaccine under field conditions
Smith TG , Millien M , Vos A , Fracciterne FA , Crowdis K , Chirodea C , Medley A , Chipman R , Qin Y , Blanton J , Wallace R . Vaccine 2017 37 (33) 4743-4749 During the 20th century parenteral vaccination of dogs at central-point locations was the foundation of successful canine rabies elimination programs in numerous countries. However, countries that remain enzootic for canine rabies have lower infrastructural development compared to countries that have achieved elimination, which may make traditional vaccination methods less successful. Alternative vaccination methods for dogs must be considered, such as oral rabies vaccine (ORV). In 2016, a traditional mass dog vaccination campaign in Haiti was supplemented with ORV to improve vaccination coverage and to evaluate the use of ORV in dogs. Blisters containing live-attenuated, vaccine strain SPBNGAS-GAS were placed in intestine bait and distributed to dogs by hand. Serum was collected from 107 dogs, aged 3-12 months with no reported prior rabies vaccination, pre-vaccination and from 78/107 dogs (72.9%) 17 days post-vaccination. The rapid florescent focus inhibition test (RFFIT) was used to detect neutralizing antibodies and an ELISA to detect rabies binding antibodies. Post-vaccination, 38/41 (92.7%) dogs that received parenteral vaccine had detectable antibody (RFFIT >0.05IU/mL), compared to 16/27 (59.3%, p<0.01) dogs that received ORV or 21/27 (77.8%) as measured by ELISA (>40% blocking, p<0.05). The fate of 291 oral vaccines was recorded; 283 dogs (97.2%) consumed the bait; 272 dogs (93.4%) were observed to puncture the blister, and only 14 blisters (4.8%) could not be retrieved by vaccinators and were potentially left in the environment. Pre-vaccination antibodies (RFFIT >0.05IU/mL) were detected in 10/107 reportedly vaccine-naive dogs (9.3%). Parenteral vaccination remains the most reliable method for ensuring adequate immune response in dogs, however ORV represents a viable strategy to supplement existing parental vaccination campaigns in hard-to-reach dog populations. The hand-out model reduces the risk of unintended contact with ORV through minimizing vaccine blisters left in the community. |
Comparison of a micro-neutralization test with the rapid fluorescent focus inhibition test for measuring rabies virus neutralizing antibodies
Smith TG , Gilbert AT . Trop Med Infect Dis 2017 2 (3) The rapid fluorescent focus inhibition test (RFFIT) is routinely used in the United States to measure rabies virus neutralizing antibodies (rVNA). RFFIT has a long history of reproducible and reliable results. The test has been modified over the years to use smaller volumes of reagents and samples, but requires a 50 muL minimum volume of test serum. To conduct pathogenesis studies, small laboratory animals such as mice are regularly tested for rVNA, but the minimum volume for a standard RFFIT may be impossible to obtain, particularly in scenarios of repeated sampling. To address this problem, a micro-neutralization test was developed previously. In the current study, the micro-neutralization test was compared to the RFFIT using 129 mouse serum samples from rabies vaccine studies. Using a cut-off value of 0.1 IU/mL, the sensitivity, specificity, and concordance of the micro-neutralization test were 100%, 97.5%, and 98%, respectively. The geometric mean titer of all samples above the cut-off was 2.0 IU/mL using RFFIT and 3.4 IU/mL using the micro-neutralization test, indicating that titers determined using the micro-neutralization test are not equivalent to RFFIT titers. Based on four rVNA-positive hamster serum samples, the intra-assay coefficient of variability was 24% and inter-assay coefficient of variability was 30.4 %. These results support continued use of the micro-neutralization test to determine rabies virus neutralizing antibody titers for low-volume serum samples. |
Assessment of the immunogenicity of rabies vaccine preserved by vaporization and delivered to the duodenal mucosa of gray foxes (Urocyon cinereoargenteus)
Smith TG , Wu X , Ellison JA , Wadhwa A , Franka R , Langham GL , Skinner BL , Hanlon CA , Bronshtein VL . Am J Vet Res 2017 78 (6) 752-756 OBJECTIVE To assess the immunogenicity of thermostable live-attenuated rabies virus (RABV) preserved by vaporization (PBV) and delivered to the duodenal mucosa of a wildlife species targeted for an oral vaccination program. ANIMALS 8 gray foxes (Urocyon cinereoargenteus). PROCEDURES Endoscopy was used to place RABV PBV (n = 3 foxes), alginate-encapsulated RABV PBV (3 foxes), or nonpreserved RABV (2 foxes) vaccine into the duodenum of foxes. Blood samples were collected weekly to monitor the immune response. Saliva samples were collected weekly and tested for virus shedding by use of a conventional reverse-transcriptase PCR assay. Foxes were euthanized 28 days after vaccine administration, and relevant tissues were collected and tested for presence of RABV. RESULTS 2 of 3 foxes that received RABV PBV and 1 of 2 foxes that received nonpreserved RABV seroconverted by day 28. None of the 3 foxes receiving alginate-encapsulated RABV PBV seroconverted. No RABV RNA was detected in saliva at any of the time points, and RABV antigen or RNA was not detected in any of the tissues obtained on day 28. None of the foxes displayed any clinical signs of rabies. CONCLUSIONS AND CLINICAL RELEVANCE Results for this study indicated that a live-attenuated RABV vaccine delivered to the duodenal mucosa can induce an immune response in gray foxes. A safe, potent, thermostable RABV vaccine that could be delivered orally to wildlife or domestic animals would enhance current rabies control and prevention efforts. |
Human Rabies - Missouri, 2014.
Pratt PD , Henschel K , Turabelidze G , Grim A , Ellison JA , Orciari L , Yager P , Franka R , Wu X , Ma X , Wadhwa A , Smith TG , Petersen B , Shiferaw M . MMWR Morb Mortal Wkly Rep 2016 65 (10) 253-256 On September 18, 2014, the Missouri Department of Health and Senior Services (MDHSS) was notified of a suspected rabies case in a Missouri resident. The patient, a man aged 52 years, lived in a rural, deeply wooded area, and bat sightings in and around his home were anecdotally reported. Exposure to bats poses a risk for rabies. After two emergency department visits for severe neck pain, paresthesia in the left arm, upper body tremors, and anxiety, he was hospitalized on September 13 for encephalitis of unknown etiology. On September 24, he received a diagnosis of rabies and on September 26, he died. Genetic sequencing tests confirmed infection with a rabies virus variant associated with tricolored bats. Health care providers need to maintain a high index of clinical suspicion for rabies in patients who have unexplained, rapidly progressive encephalitis, and adhere to recommended infection control practices when examining and treating patients with suspected infectious diseases. |
Rabies vaccine preserved by vaporization is thermostable and immunogenic
Smith TG , Siirin M , Wu X , Hanlon CA , Bronshtein V . Vaccine 2015 33 (19) 2203-2206 A rabies vaccine that is thermostable over a range of ambient environmental temperatures would be highly advantageous, especially for tropical regions with challenging cold-chain storage where canine rabies remains enzootic resulting in preventable human mortality. Live attenuated rabies virus (RABV) strain ERAg333 (R333E) was preserved by vaporization (PBV) in a dry, stable foam. RABV stabilized using this process remains viable for at least 23 months at 22 degrees C, 15 months at 37 degrees C, and 3h at 80 degrees C. An antigen capture assay revealed RABV PBV inactivated by irradiation contained similar levels of antigen as a commercial vaccine. Viability and antigen capture testing confirmed that the PBV process stabilized RABV with no significant loss in titer or antigen content. Live attenuated and inactivated RABV PBV both effectively induced RABV neutralizing antibodies and protected mice from peripheral rabies virus challenge. These results demonstrate that PBV is an efficient method for RABV stabilization. |
The feasibility of rabies virus-vectored immunocontraception in a mouse model
Wu XF , Smith TG , Franka R , Wang M , Carson WC , Rupprecht CE . Trials Vaccinol 2014 3 11-18 Immunocontraceptive vaccines may be an alternative to surgical sterilization. Dual rabies vaccination and dog population management is a helpful tool for rabies prevention. A synthetic gonadotropin-releasing hormone (GnRH) peptide coupled to a carrier protein or T cell epitope is efficacious in inducing immunocontraception in a variety of mammals. However, virus-vectored GnRH recombinant vaccines have advantages over the conjugation method. In a previous in vitro study, we were able to insert a GnRH-coding sequence into the rabies virus (RABV) glycoprotein (G) gene, and the recombinant viruses grew to high titers in cells. Here, we further focused on the RABV G in accepting various copy numbers of GnRH. We demonstrated although RABV G protein with up to 4 copies of GnRH was well expressed, the recombinant virus was recovered only when 2 copies of GnRH (20 amino acids) were incorporated into the G, indicating a possible insertion limit in making a full infectious clone. The investigation provides insight into the utility of RABV G as a carrier for small peptides and its suitability for vaccine studies. Following our previous study, we selected ERAg3p/2 GnRH and tested the construct in mice. The vaccine induced >=80% infertility after three doses without any adjuvant, in live (8 of 10 mice infertility) or inactivated (13 of 14 mice infertility) formulations; while the pregnancy rate was 100% (10 of 10 mice) in the controls. This initial success of immunocontraception in mice is promising, and we are now optimizing the vaccine formulation by using adjuvants and exploring novel delivery methods to minimize the dosage. |
Current and future tools for global canine rabies elimination
Franka R , Smith TG , Dyer JL , Wu X , Niezgoda M , Rupprecht CE . Antiviral Res 2013 100 (1) 220-5 Even though rabies is almost uniformly fatal, it is readily preventable with currently available tools. Vaccination is highly efficacious for the pre-exposure prophylaxis (PrEP) of rabies in humans and animals, and prompt postexposure prophylaxis (PEP) with vaccine and rabies immune globulin (RIG) can reliably prevent disease in humans. However, access to these tools and knowledge of their proper use are often limited, especially in impoverished, rabies-enzootic countries with the highest disease burden. In the absence of reliable diagnostic capacity and risk assessments, vaccines and RIG are often administered inappropriately, leading to chronic supply shortages and otherwise preventable deaths. Rather than focusing solely on human prophylaxis, it is more cost-effective over the long term to eliminate canine rabies in its natural terrestrial reservoirs. Because more than 99% of human rabies deaths result from dog bites, prevention efforts should focus on dogs. A versatile "One Health" strategy for canine rabies elimination should aim to create sustainable herd immunity in dogs, using proven vaccination strategies at the local level, coupled with community education and humane population management. Such strategies have succeeded in both developed and developing countries, and can be adapted to any locality. Numerous examples in Africa, Asia, and Latin America have shown that community-based, locally guided vaccination and education programs, based on a shared vision and long-term commitment, can eliminate canine rabies. Such programs should have specific goals and measurable outcomes, and should be conducted under the guidance of supportive governments, in collaboration with international partners and nongovernmental organizations. In addition to currently available tools, rabies prevention can be augmented by new dose-sparing human vaccine schedules, alternative routes of vaccine administration, monoclonal antibodies as an alternative to RIG, sensitive and specific point-of-care diagnostics and the development of canine immunocontraceptive methods. Accurate risk assessments of potential human exposures and support for decentralized laboratory capacity will be essential to ensure the most effective utilization of vaccines and RIG until canine rabies has been eliminated. |
An electrochemiluminescence assay for analysis of rabies virus glycoprotein content in rabies vaccines
Smith TG , Ellison JA , Ma X , Kuzmina N , Carson W , Rupprecht CE . Vaccine 2013 31 (33) 3333-8 Vaccine potency testing is necessary to evaluate the immunogenicity of inactivated rabies virus (RABV) vaccine preparations before human or veterinary application. Currently, the NIH test is recommended by the WHO expert committee to evaluate RABV vaccine potency. However, numerous disadvantages are inherent concerning cost, number of animals and biosafety requirements. As such, several in vitro methods have been proposed for the evaluation of vaccines based on RABV glycoprotein (G) quality and quantity, which is expected to correlate with vaccine potency. In this study an antigen-capture electrochemiluminescent (ECL) assay was developed utilizing anti-RABV G monoclonal antibodies (MAb) to quantify RABV G. One MAb 2-21-14 was specific for a conformational epitope so that only immunogenic, natively folded G was captured in the assay. A second MAb (62-80-6) that binds a linear epitope or MAb 2-21-14 was used for detection of RABV G. Vaccine efficacy was also assessed in vivo using pre-exposure vaccination of mice. Purified native RABV G induced a RABV neutralizing antibody (rVNA) response with a geometric mean titer of 4.2IU/ml and protected 100% of immunized mice against RABV challenge, while an experimental vaccine with a lower quality and quantity of G induced a rVNA titer<0.05IU/ml and protected <50% of immunized mice. These preliminary results support the hypothesis that in vivo immunogenicity may be predicted from the in vitro measurement of RABV G using an ECL assay. Based upon these results, the ECL assay may have utility in replacement of the NIH test. |
From brain passage to cell adaptation: the road of human rabies vaccine development
Wu X , Smith TG , Rupprecht CE . Expert Rev Vaccines 2011 10 (11) 1597-608 A major challenge for global rabies prevention and control is the lack of sufficient and affordable high quality vaccines. Such candidates should be pure, potent, safe, effective and economical to produce, with broad cross-reactivity against viral variants of public health and veterinary importance. The history of licensed human vaccines reviewed herein demonstrates clearly how the field has evolved to the current state of more passive development and postexposure management. Modern cell culture techniques provide adequate viral substrates for production of representative verified virus seeds. In contrast to outdated nervous tissue-based rabies vaccines, once a suitable substrate is identified, production of high titer virus results in a major qualitative and quantitative difference. Given the current scenario of only inactivated vaccines for humans, highly cell-adapted and stable, attenuated rabies viruses are ideal candidates for consideration to meet the need for seed viruses in the future. |
Design of future rabies biologics and antiviral drugs
Smith TG , Wu X , Franka R , Rupprecht CE . Adv Virus Res 2011 79 345-63 In recent years, no major paradigm shifts have occurred in the utilization of new products for the prevention and control of rabies. Development of new cost-effective rabies biologics and antiviral drugs is critical in continuing to prevent and reduce disease. Current rabies vaccines are highly effective but have developed largely based on technical improvements in the vaccine industry. In the future, alternative approaches for improved vaccines, including novel avirulent rabies virus (RABV) vectors, should be pursued. Any rabies vaccine that is effective without the need for rabies immune globulin (RIG) will contribute fundamentally to disease prevention by reducing the cost and complexity of postexposure prophylaxis (PEP). The lack of high quality, affordable RIG is a continuing problem. Virus-specific monoclonal antibodies (mAbs) will soon fulfill the PEP requirement for passive immunity, currently met with RIG. Several relevant strategies for mAb production, including use of transgenic mice, humanization of mouse mAbs, and generation of human immune libraries, are underway. As a result of successful PEP and pre-exposure prophylaxis in developed countries, until recently, no significant focused efforts have been devoted to RABV-specific antiviral agents. To date, combination therapy including broad spectrum antiviral agents has been successful in only one case, and reports of antiviral activity are often conflicting. Current antiviral strategies target either the nucleoprotein or phosphoprotein, but drugs targeting the viral polymerase should be considered. Considering the lag from creation of new concepts to experimental development and clinical trials, many years will likely elapse between today's ideas and tomorrow's practices. |
- Page last reviewed:Feb 1, 2024
- Page last updated:Nov 04, 2024
- Content source:
- Powered by CDC PHGKB Infrastructure