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Molecules (Basel, Switzerland) Feb 2021Varicella-zoster virus (VZV), a common and ubiquitous human-restricted pathogen, causes a primary infection (varicella or chickenpox) followed by establishment of... (Review)
Review
Varicella-zoster virus (VZV), a common and ubiquitous human-restricted pathogen, causes a primary infection (varicella or chickenpox) followed by establishment of latency in sensory ganglia. The virus can reactivate, causing herpes zoster (HZ, shingles) and leading to significant morbidity but rarely mortality, although in immunocompromised hosts, VZV can cause severe disseminated and occasionally fatal disease. We discuss VZV diseases and the decrease in their incidence due to the introduction of live-attenuated vaccines to prevent varicella or HZ. We also focus on acyclovir, valacyclovir, and famciclovir (FDA approved drugs to treat VZV infections), brivudine (used in some European countries) and amenamevir (a helicase-primase inhibitor, approved in Japan) that augur the beginning of a new era of anti-VZV therapy. Valnivudine hydrochloride (FV-100) and valomaciclovir stearate (in advanced stage of development) and several new molecules potentially good as anti-VZV candidates described during the last year are examined. We reflect on the role of antiviral agents in the treatment of VZV-associated diseases, as a large percentage of the at-risk population is not immunized, and on the limitations of currently FDA-approved anti-VZV drugs. Their low efficacy in controlling HZ pain and post-herpetic neuralgia development, and the need of multiple dosing regimens requiring daily dose adaptation for patients with renal failure urges the development of novel anti-VZV drugs.
Topics: Antiviral Agents; Encephalitis, Varicella Zoster; Herpesvirus 3, Human; Humans; Microbial Sensitivity Tests; Pyrimidine Nucleosides
PubMed: 33672709
DOI: 10.3390/molecules26041132 -
Viruses May 2022The replication of varicella-zoster virus (VZV) in skin is critical to its pathogenesis and spread. Primary infection causes chickenpox, which is characterised by... (Review)
Review
The replication of varicella-zoster virus (VZV) in skin is critical to its pathogenesis and spread. Primary infection causes chickenpox, which is characterised by centrally distributed skin blistering lesions that are rich in infectious virus. Cell-free virus in the cutaneous blistering lesions not only spreads to cause further cases, but infects sensory nerve endings, leading to the establishment of lifelong latency in sensory and autonomic ganglia. The reactivation of virus to cause herpes zoster is again characterised by localised painful skin blistering rash containing infectious virus. The development of and models of VZV skin replication has revealed aspects of VZV replication and pathogenesis in this important target organ and improved our understanding of the vaccine strain vOKa attenuation. In this review, we outline the current knowledge on VZV interaction with host signalling pathways, the viral association with proteins associated with epidermal terminal differentiation, and how these interconnect with the VZV life cycle to facilitate viral replication and shedding.
Topics: Biology; Chickenpox; Herpes Zoster; Herpesvirus 3, Human; Humans; Skin
PubMed: 35632723
DOI: 10.3390/v14050982 -
Viruses Oct 2021Varicella-zoster virus (VZV) is a human herpes virus which causes varicella (chicken pox) as a primary infection, and, following a variable period of latency in neurons... (Review)
Review
Varicella-zoster virus (VZV) is a human herpes virus which causes varicella (chicken pox) as a primary infection, and, following a variable period of latency in neurons in the peripheral ganglia, may reactivate to cause herpes zoster (shingles) as well as a variety of neurological syndromes. In this overview we consider some recent issues in alphaherpesvirus latency with special focus on VZV ganglionic latency. A key question is the nature and extent of viral gene transcription during viral latency. While it is known that this is highly restricted, it is only recently that the very high degree of that restriction has been clarified, with both VZV gene 63-encoded transcripts and discovery of a novel VZV transcript (VLT) that maps antisense to the viral transactivator gene 61. It has also emerged in recent years that there is significant epigenetic regulation of VZV gene transcription, and the mechanisms underlying this are complex and being unraveled. The last few years has also seen an increased interest in the immunological aspects of VZV latency and reactivation, in particular from the perspective of inborn errors of host immunity that predispose to different VZV reactivation syndromes.
Topics: Chickenpox; Epigenesis, Genetic; Genes, Viral; Herpes Zoster; Herpesvirus 3, Human; Humans; Neurons; Varicella Zoster Virus Infection; Virus Latency
PubMed: 34696448
DOI: 10.3390/v13102018 -
Viruses May 2022Pseudorabies virus (PRV), the causative agent of Aujeszky's disease, has a broad host range including most mammals and avian species. In 2011, a PRV variant emerged in... (Review)
Review
Pseudorabies virus (PRV), the causative agent of Aujeszky's disease, has a broad host range including most mammals and avian species. In 2011, a PRV variant emerged in many Bartha K61-vaccinated pig herds in China and has attracted more and more attention due to its serious threat to domestic and wild animals, and even human beings. The PRV variant has been spreading in China for more than 10 years, and considerable research progresses about its molecular biology, pathogenesis, transmission, and host-virus interactions have been made. This review is mainly organized into four sections including outbreak and genomic evolution characteristics of PRV variants, progresses of PRV variant vaccine development, the pathogenicity and transmission of PRV variants among different species of animals, and the zoonotic potential of PRV variants. Considering PRV has caused a huge economic loss of animals and is a potential threat to public health, it is necessary to extensively explore the mechanisms involved in its replication, pathogenesis, and transmission in order to ultimately eradicate it in China.
Topics: Animals; Genomics; Herpesvirus 1, Suid; Mammals; Pseudorabies; Swine; Swine Diseases; Vaccination
PubMed: 35632745
DOI: 10.3390/v14051003 -
The Journal of Infectious Diseases Sep 2021Michiaki Takahashi developed the live attenuated varicella vaccine in 1974 . This was the first, and is still the only, herpesvirus vaccine. Early studies showed...
Michiaki Takahashi developed the live attenuated varicella vaccine in 1974 . This was the first, and is still the only, herpesvirus vaccine. Early studies showed promise, but the vaccine was rigorously tested on immunosuppressed patients because of their high risk of fatal varicella; vaccination proved to be lifesaving. Subsequently, the vaccine was found to be safe and effective in healthy children. Eventually, varicella vaccine became a component of measles mumps rubella vaccine, 2 doses of which are administered in the USA to ~90% of children. The incidence of varicella has dropped dramatically in the USA since vaccine-licensure in 1995. Varicella vaccine is also associated with a decreased incidence of zoster and is protective for susceptible adults. Today, immunocompromised individuals are protected against varicella due to vaccine-induced herd immunity. Latent infection with varicella zoster virus occurs after vaccination; however, the vaccine strain is impaired for its ability to reactivate.
Topics: Antigens, Viral; Chickenpox; Chickenpox Vaccine; Herpes Zoster; Herpes Zoster Vaccine; Herpesvirus 3, Human; Humans; Incidence; Measles-Mumps-Rubella Vaccine; United States; Vaccination; Vaccines, Attenuated; Vaccines, Combined
PubMed: 34590140
DOI: 10.1093/infdis/jiaa573 -
Viruses Jul 2023Varicella-Zoster virus (VZV) is a pathogenic human alpha herpes virus that causes varicella (chicken pox) as a primary infection and, following a variable period of... (Review)
Review
Varicella-Zoster virus (VZV) is a pathogenic human alpha herpes virus that causes varicella (chicken pox) as a primary infection and, following a variable period of latency in different ganglionic neurons, it reactivates to produce herpes zoster (shingles). The focus of this review is on the wide spectrum of the possible neurological manifestations of VZV reactivation. While the most frequent reactivation syndrome is herpes zoster, this may be followed by the serious and painful post-herpetic neuralgia (PHN) and by many other neurological conditions. Prominent among these conditions is a VZV vasculopathy, but the role of VZV in causing giant cell arteritis (GCA) is currently controversial. VZV reactivation can also cause segmental motor weakness, myelitis, cranial nerve syndromes, Guillain-Barre syndrome, meningoencephalitis, and zoster sine herpete, where a neurological syndrome occurs in the absence of the zoster rash. The field is complicated by the relatively few cases of neurological complications described and by the issue of causation when a neurological condition is not manifest at the same time as the zoster rash.
Topics: Humans; Herpesvirus 3, Human; Herpes Zoster; Chickenpox; Neuralgia, Postherpetic; Alphavirus; Exanthema
PubMed: 37632006
DOI: 10.3390/v15081663 -
Human Vaccines & Immunotherapeutics Dec 2023The objective of this study was to critically review the cost-effectiveness (CE) of the recombinant zoster vaccine (RZV) against herpes zoster (HZ). A literature review... (Review)
Review
The objective of this study was to critically review the cost-effectiveness (CE) of the recombinant zoster vaccine (RZV) against herpes zoster (HZ). A literature review was conducted in PubMed, Embase, and Cochrane between January 1, 2017, and February 28, 2022, and on select public healthcare agency websites to identify and collect data from CE studies comparing RZV to zoster vaccine live (ZVL) or to no vaccination. Study characteristics, inputs, and outputs were collected. The overall CE of RZV was assessed. RZV vaccination against HZ is cost-effective in 15 out of 18 studies included in the present review. Varying incremental cost-effectiveness ratios (ICERs) observed may be associated with different assumptions on the duration of protection of RZV, as well as different combinations of structural and disease-related study (model) inputs driving the estimation of ICERs.
Topics: Humans; Herpes Zoster Vaccine; Cost-Benefit Analysis; Herpes Zoster; Herpesvirus 3, Human; Vaccination; Vaccines, Synthetic; Neuralgia, Postherpetic
PubMed: 36916240
DOI: 10.1080/21645515.2023.2168952 -
Clinical Infectious Diseases : An... Apr 2022This ongoing follow-up study evaluated the persistence of efficacy and immune responses for 6 additional years in adults vaccinated with the glycoprotein E (gE)-based...
The Adjuvanted Recombinant Zoster Vaccine Confers Long-Term Protection Against Herpes Zoster: Interim Results of an Extension Study of the Pivotal Phase 3 Clinical Trials ZOE-50 and ZOE-70.
BACKGROUND
This ongoing follow-up study evaluated the persistence of efficacy and immune responses for 6 additional years in adults vaccinated with the glycoprotein E (gE)-based adjuvanted recombinant zoster vaccine (RZV) at age ≥50 years in 2 pivotal efficacy trials (ZOE-50 and ZOE-70). The present interim analysis was performed after ≥2 additional years of follow-up (between 5.1 and 7.1 years [mean] post-vaccination) and includes partial data for year (Y) 8 post-vaccination.
METHODS
Annual assessments were performed for efficacy against herpes zoster (HZ) from Y6 post-vaccination and for anti-gE antibody concentrations and gE-specific CD4[2+] T-cell (expressing ≥2 of 4 assessed activation markers) frequencies from Y5 post-vaccination.
RESULTS
Of 7413 participants enrolled for the long-term efficacy assessment, 7277 (mean age at vaccination, 67.2 years), 813, and 108 were included in the cohorts evaluating efficacy, humoral immune responses, and cell-mediated immune responses, respectively. Efficacy of RZV against HZ through this interim analysis was 84.0% (95% confidence interval [CI], 75.9-89.8) from the start of this follow-up study and 90.9% (95% CI, 88.2-93.2) from vaccination in ZOE-50/70. Annual vaccine efficacy estimates were >84% for each year since vaccination and remained stable through this interim analysis. Anti-gE antibody geometric mean concentrations and median frequencies of gE-specific CD4[2+] T cells reached a plateau at approximately 6-fold above pre-vaccination levels.
CONCLUSIONS
Efficacy against HZ and immune responses to RZV remained high, suggesting that the clinical benefit of RZV in older adults is sustained for at least 7 years post-vaccination. Clinical Trials Registration. NCT02723773.
Topics: Adjuvants, Immunologic; Aged; Follow-Up Studies; Herpes Zoster; Herpes Zoster Vaccine; Herpesvirus 3, Human; Humans; Middle Aged; Vaccines, Synthetic
PubMed: 34283213
DOI: 10.1093/cid/ciab629 -
Journal of Virology Aug 2023Feline herpesvirus type 1 (FHV-1) is an enveloped dsDNA virus belonging to the family and is considered one of the two primary viral etiological factors of feline upper...
Feline herpesvirus type 1 (FHV-1) is an enveloped dsDNA virus belonging to the family and is considered one of the two primary viral etiological factors of feline upper respiratory tract disease. In this study, we investigated the entry of FHV-1 into host cells using two models: the AK-D cell line and primary feline skin fibroblasts (FSFs). We employed confocal microscopy, siRNA silencing, and selective inhibitors of various entry pathways. Our observations revealed that the virus enters cells via pH and dynamin-dependent endocytosis, as the infection was significantly inhibited by NHCl, bafilomycin A1, dynasore, and mitmab. Additionally, genistein, nystatin, and filipin treatments, siRNA knock-down of caveolin-1, as well as FHV-1 and caveolin-1 colocalization suggest the involvement of caveolin-mediated endocytosis during the entry process. siRNA knock-down of clathrin heavy chain and analysis of virus particle colocalization with clathrin indicated that clathrin-mediated endocytosis also takes part in the primary cells. This is the first study to systematically examine FHV-1 entry into host cells, and for the first time, we describe FHV-1 replication in AK-D and FSFs. IMPORTANCE Feline herpesvirus 1 (FHV-1) is one of the most prevalent viruses in cats, causing feline viral rhinotracheitis, which is responsible for over half of viral upper respiratory diseases in cats and can lead to ocular lesions resulting in loss of sight. Although the available vaccine reduces the severity of the disease, it does not prevent infection or limit virus shedding. Despite the clinical relevance, the entry mechanisms of FHV-1 have not been thoroughly studied. Considering the limitations of commonly used models based on immortalized cells, we sought to verify our findings using primary feline skin fibroblasts, the natural target for infection in cats.
Topics: Animals; Cats; Cat Diseases; Caveolin 1; Clathrin; Endocytosis; Herpesviridae Infections; RNA, Small Interfering; Varicellovirus
PubMed: 37493545
DOI: 10.1128/jvi.00681-23 -
Clinical Infectious Diseases : An... Oct 2020The primary reported risk factors for herpes zoster (HZ) include increasing age and immunodeficiency, yet estimates of HZ risk by immunocompromising condition have not...
BACKGROUND
The primary reported risk factors for herpes zoster (HZ) include increasing age and immunodeficiency, yet estimates of HZ risk by immunocompromising condition have not been well characterized. We undertook a systematic literature review to estimate the HZ risk in immunocompromised patients.
METHODS
We systematically reviewed studies that examined the risk of HZ and associated complications in adult patients with hematopoietic cell transplants (HCT), cancer, human immunodeficiency virus (HIV), and solid organ transplant (SOT). We identified studies in PubMed, Embase, Medline, Cochrane, Scopus, and clinicaltrials.gov that presented original data from the United States and were published after 1992. We assessed the risk of bias with Cochrane or Grading of Recommendations Assessment, Development, and Evaluation methods.
RESULTS
We identified and screened 3765 records and synthesized 34 studies with low or moderate risks of bias. Most studies that were included (32/34) reported at least 1 estimate of the HZ cumulative incidence (range, 0-41%). There were 12 studies that reported HZ incidences that varied widely within and between immunocompromised populations. Incidence estimates ranged from 9 to 92 HZ cases/1000 patient-years and were highest in HCT, followed by hematologic malignancies, SOT, and solid tumor malignancies, and were lowest in people living with HIV. Among 17 HCT studies, the absence of or use of antiviral prophylaxis at <1 year post-transplant was associated with a higher HZ incidence.
CONCLUSIONS
HZ was common among all immunocompromised populations studied, exceeding the expected HZ incidence among immunocompetent adults aged ≥60 years. Better evidence of the incidence of HZ complications and their severity in immunocompromised populations is needed to inform economic and HZ vaccine policies.
Topics: Adult; Herpes Zoster; Herpes Zoster Vaccine; Herpesvirus 3, Human; Humans; Immunocompromised Host; Incidence; Middle Aged; Neuralgia, Postherpetic; United States
PubMed: 31677266
DOI: 10.1093/cid/ciz1090