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Virulence Dec 2023Influenza viruses, including four major types (A, B, C, and D), can cause mild-to-severe and lethal diseases in humans and animals. Influenza viruses evolve rapidly... (Review)
Review
Influenza viruses, including four major types (A, B, C, and D), can cause mild-to-severe and lethal diseases in humans and animals. Influenza viruses evolve rapidly through antigenic drift (mutation) and shift (reassortment of the segmented viral genome). New variants, strains, and subtypes have emerged frequently, causing epidemic, zoonotic, and pandemic infections, despite currently available vaccines and antiviral drugs. In recent years, avian influenza viruses, such as H5 and H7 subtypes, have caused hundreds to thousands of zoonotic infections in humans with high case fatality rates. The likelihood of these animal influenza viruses acquiring airborne transmission in humans through viral evolution poses great concern for the next pandemic. Severe influenza viral disease is caused by both direct viral cytopathic effects and exacerbated host immune response against high viral loads. Studies have identified various mutations in viral genes that increase viral replication and transmission, alter tissue tropism or species specificity, and evade antivirals or pre-existing immunity. Significant progress has also been made in identifying and characterizing the host components that mediate antiviral responses, pro-viral functions, or immunopathogenesis following influenza viral infections. This review summarizes the current knowledge on viral determinants of influenza virulence and pathogenicity, protective and immunopathogenic aspects of host innate and adaptive immune responses, and antiviral and pro-viral roles of host factors and cellular signalling pathways. Understanding the molecular mechanisms of viral virulence factors and virus-host interactions is critical for the development of preventive and therapeutic measures against influenza diseases.
Topics: Humans; Animals; Influenza, Human; Virulence; Orthomyxoviridae Infections; Influenza A virus; Orthomyxoviridae; Influenza Vaccines; Antiviral Agents; Virus Replication; Influenza in Birds
PubMed: 37339323
DOI: 10.1080/21505594.2023.2223057 -
Expert Opinion on Pharmacotherapy 2023On 31 July 2023, the United States Department of Health and Human Services announced the formation of the Office of Long COVID Research and Practice and the United...
INTRODUCTION
On 31 July 2023, the United States Department of Health and Human Services announced the formation of the Office of Long COVID Research and Practice and the United States National Institutes of Health opened enrollment for RECOVER-Vital, a randomized study to evaluate new treatment options for long Coronavirus (long COVID).
AREAS COVERED
The RECOVER Initiative is a $1.15 billion research platform intended to describe, categorize, treat, and prevent long-term symptoms following infection by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS‑CoV‑2), the virus that causes Coronavirus (COVID-19). More than 200 symptoms have been associated with long COVID, potentially affecting nearly all body systems, and current estimates suggest that between 7 million and 23 million Americans have developed long COVID. However, there are no approved treatments for this condition.
EXPERT OPINION
The first prospective, randomized study of the RECOVER research initiative, RECOVER-Vital, will evaluate the SARS-CoV-2 antiviral nirmatrelvir/ritonavir (Paxlovid) as a potential treatment for long COVID. This manuscript explores what is known about Paxlovid to treat and prevent long COVID and examines the rationale for addressing this condition with an antiviral agent.
Topics: Humans; Antiviral Agents; COVID-19; Post-Acute COVID-19 Syndrome; Prospective Studies; Ritonavir; SARS-CoV-2; Randomized Controlled Trials as Topic
PubMed: 37731377
DOI: 10.1080/14656566.2023.2262387 -
Transplant International : Official... 2023Despite advances in monitoring and treatment, cytomegalovirus (CMV) infections remain one of the most common complications after solid organ transplantation (SOT). CMV... (Review)
Review
Despite advances in monitoring and treatment, cytomegalovirus (CMV) infections remain one of the most common complications after solid organ transplantation (SOT). CMV infection may fail to respond to standard first- and second-line antiviral therapies with or without the presence of antiviral resistance to these therapies. This failure to respond after 14 days of appropriate treatment is referred to as "resistant/refractory CMV." Limited data on refractory CMV without antiviral resistance are available. Reported rates of resistant CMV are up to 18% in SOT recipients treated for CMV. Therapeutic options for treating these infections are limited due to the toxicity of the agent used or transplant-related complications. This is often the challenge with conventional agents such as ganciclovir, foscarnet and cidofovir. Recent introduction of new CMV agents including maribavir and letermovir as well as the use of adoptive T cell therapy may improve the outcome of these difficult-to-treat infections in SOT recipients. In this expert review, we focus on new treatment options for resistant/refractory CMV infection and disease in SOT recipients, with an emphasis on maribavir, letermovir, and adoptive T cell therapy.
Topics: Humans; Antiviral Agents; Cytomegalovirus; Cytomegalovirus Infections; Acetates; Ganciclovir
PubMed: 37901297
DOI: 10.3389/ti.2023.11785 -
International Journal of Antimicrobial... Aug 2023Cytomegalovirus (CMV) is a common infection encountered in immunocompromised patients. It is associated with high morbidity and mortality, particularly in patients... (Review)
Review
Cytomegalovirus (CMV) is a common infection encountered in immunocompromised patients. It is associated with high morbidity and mortality, particularly in patients undergoing allogeneic (allo-) haematopoietic stem cell transplantation (HSCT). This review presents the most recent management strategies for CMV infection in allo-HSCT recipients. Pre-emptive treatment (PET) consists of frequent monitoring of CMV polymerase chain reaction (PCR) after HSCT; this has been the standard of care for prevention of CMV for many years, given the potential drug toxicity associated with the traditional drugs used as prophylaxis. However, letermovir, recently approved as a chemoprophylactic agent for prevention of CMV, has shown great efficacy in randomized clinical trials and real-world data. Treatment of CMV disease is becoming increasingly difficult, and must take into account the patient's risk profile and the potential for CMV drug resistance. Different treatment strategies exist for refractory and resistant CMV disease. Maribavir is a new drug that showed promising results in the treatment of refractory and resistant CMV disease. Other alternative treatments, such as cellular adoptive immunotherapy, artesunate and leflunomide, may play an adjunctive role in the treatment of challenging cases; however, further investigation is warranted.
Topics: Humans; Antiviral Agents; Cytomegalovirus Infections; Cytomegalovirus; Transplantation, Homologous; Hematopoietic Stem Cell Transplantation
PubMed: 37220849
DOI: 10.1016/j.ijantimicag.2023.106860 -
Virus Research Sep 2023Vaccines and drugs are two effective medical interventions to mitigate SARS-CoV-2 infection. Three SARS-CoV-2 inhibitors, remdesivir, paxlovid, and molnupiravir, have...
Vaccines and drugs are two effective medical interventions to mitigate SARS-CoV-2 infection. Three SARS-CoV-2 inhibitors, remdesivir, paxlovid, and molnupiravir, have been approved for treating COVID-19 patients, but more are needed, because each drug has its limitation of usage and SARS-CoV-2 constantly develops drug resistance mutations. In addition, SARS-CoV-2 drugs have the potential to be repurposed to inhibit new human coronaviruses, thus help to prepare for future coronavirus outbreaks. We have screened a library of microbial metabolites to discover new SARS-CoV-2 inhibitors. To facilitate this screening effort, we generated a recombinant SARS-CoV-2 Delta variant carrying the nano luciferase as a reporter for measuring viral infection. Six compounds were found to inhibit SARS-CoV-2 at the half maximal inhibitory concentration (IC50) below 1 μM, including the anthracycline drug aclarubicin that markedly reduced viral RNA-dependent RNA polymerase (RdRp)-mediated gene expression, whereas other anthracyclines inhibited SARS-CoV-2 by activating the expression of interferon and antiviral genes. As the most commonly prescribed anti-cancer drugs, anthracyclines hold the promise of becoming new SARS-CoV-2 inhibitors.
Topics: Humans; COVID-19; SARS-CoV-2; Anthracyclines; Antiviral Agents
PubMed: 37379907
DOI: 10.1016/j.virusres.2023.199164 -
Frontiers in Bioscience (Landmark... Oct 2023Several antiviral drugs are clinically approved to treat influenza that is a highly prevalent acute respiratory disease. However, emerging drug-resistant virus strains... (Review)
Review
Several antiviral drugs are clinically approved to treat influenza that is a highly prevalent acute respiratory disease. However, emerging drug-resistant virus strains undermine treatment efficacy, highlighting the exigency for novel antiviral drugs to counter these drug-resistant strains. Plants and their derivates have been historically utilized as medicinal remedies, and extensive studies have evidenced the antiviral potential of phytochemicals. Notably, apigenin is a predominant flavonoid with minimal toxicity and substantial therapeutic effects in various disease models. Despite its many anti-inflammatory, anti-oxidant, anti-cancer, anti-bacterial, and other beneficial bioactivities, existing reviews have yet to focus on apigenin's antiviral effects. Therefore, this review elucidates apigenin's therapeutic and antiviral properties and , discussing its mode of action and future prospects. Apigenin's remarkable inhibition by modulating multiple mechanisms against viruses has promising potential for novel plant-derived antiviral drugs and further clinical study developments.
Topics: Humans; Apigenin; Virus Diseases; Neoplasms; Flavonoids; Antiviral Agents
PubMed: 37919082
DOI: 10.31083/j.fbl2810237 -
Nature Reviews. Drug Discovery Jul 2023During the coronavirus disease 2019 (COVID-19) pandemic, a wave of rapid and collaborative drug discovery efforts took place in academia and industry, culminating in... (Review)
Review
During the coronavirus disease 2019 (COVID-19) pandemic, a wave of rapid and collaborative drug discovery efforts took place in academia and industry, culminating in several therapeutics being discovered, approved and deployed in a 2-year time frame. This article summarizes the collective experience of several pharmaceutical companies and academic collaborations that were active in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antiviral discovery. We outline our opinions and experiences on key stages in the small-molecule drug discovery process: target selection, medicinal chemistry, antiviral assays, animal efficacy and attempts to pre-empt resistance. We propose strategies that could accelerate future efforts and argue that a key bottleneck is the lack of quality chemical probes around understudied viral targets, which would serve as a starting point for drug discovery. Considering the small size of the viral proteome, comprehensively building an arsenal of probes for proteins in viruses of pandemic concern is a worthwhile and tractable challenge for the community.
Topics: Animals; COVID-19; Antiviral Agents; SARS-CoV-2; Drug Discovery; Pandemics
PubMed: 37173515
DOI: 10.1038/s41573-023-00692-8 -
Drug Resistance Updates : Reviews and... Sep 2023
Topics: Humans; Antiviral Agents; SARS-CoV-2; COVID-19
PubMed: 37390619
DOI: 10.1016/j.drup.2023.100986 -
Nature Communications Jul 2023Ensitrelvir, an oral antiviral agent that targets a SARS-CoV-2 main protease (3CLpro or Nsp5), is clinically useful against SARS-CoV-2 including its omicron variants....
Ensitrelvir, an oral antiviral agent that targets a SARS-CoV-2 main protease (3CLpro or Nsp5), is clinically useful against SARS-CoV-2 including its omicron variants. Since most omicron subvariants have reduced sensitivity to most monoclonal antibody therapies, SARS-CoV-2 resistance to other antivirals including main protease inhibitors such as ensitrelvir is a major public health concern. Here, repeating passages of SARS-CoV-2 in the presence of ensitrelvir revealed that the M49L and E166A substitutions in Nsp5 are responsible for reduced sensitivity to ensitrelvir. Both substitutions reduced in vitro virus growth in the absence of ensitrelvir. The combination of the M49L and E166A substitutions allowed the virus to largely evade the suppressive effect of ensitrelvir in vitro. The virus possessing Nsp5-M49L showed similar pathogenicity to wild-type virus, whereas the virus possessing Nsp5-E166A or Nsp5-M49L/E166A slightly attenuated. Ensitrelvir treatment of hamsters infected with the virus possessing Nsp5-M49L/E166A was ineffective; however, nirmatrelvir or molnupiravir treatment was effective. Therefore, it is important to closely monitor the emergence of ensitrelvir-resistant SARS-CoV-2 variants to guide antiviral treatment selection.
Topics: Animals; Cricetinae; COVID-19; SARS-CoV-2; Antiviral Agents
PubMed: 37454219
DOI: 10.1038/s41467-023-40018-1 -
International Journal of Molecular... Aug 2023The majority of antivirals available target viral proteins; however, RNA is emerging as a new and promising antiviral target due to the presence of highly structured RNA... (Review)
Review
The majority of antivirals available target viral proteins; however, RNA is emerging as a new and promising antiviral target due to the presence of highly structured RNA in viral genomes fundamental for their replication cycle. Here, we discuss methods for the identification of RNA-targeting compounds, starting from the determination of RNA structures either from purified RNA or in living cells, followed by in silico screening on RNA and phenotypic assays to evaluate viral inhibition. Moreover, we review the small molecules known to target the programmed ribosomal frameshifting element of SARS-CoV-2, the internal ribosomal entry site of different viruses, and RNA elements of HIV.
Topics: Humans; RNA, Viral; COVID-19; SARS-CoV-2; Antiviral Agents; Biological Assay
PubMed: 37686306
DOI: 10.3390/ijms241713500