Experimental Treatment with Favipiravir for Ebola Virus Disease (the JIKI Trial): A Historically Controlled, Single-Arm Proof-of-Concept Trial in Guinea

Vector Competence of Eucampsipoda africana (Diptera: Nycteribiidae) for Marburg Virus Transmission in Rousettus aegyptiacus (Chiroptera: Pteropodidae)

This study aimed to determine the vector competence of bat-associated nycteribiid flies (Eucamsipoda africana) for Marburg virus (MARV) in the Egyptian Rousette Bat (ERB), Rousettus aegyptiacus. In flies fed on subcutaneously infected ERBs and tested from 3 to 43 days post infection (dpi), MARV was detected only in those that took blood during the peak of viremia, 5-7 dpi. Seroconversion did not occur in control bats in contact with MARV-infected bats infested with bat flies up to 43 days post exposure. In flies inoculated intra-coelomically with MARV and tested on days 0-29 post inoculation, only those assayed on day 0 and day 7 after inoculation were positive by q-RT-PCR, but the virus concentration was consistent with that of the inoculum. Bats remained MARV-seronegative up to 38 days after infestation and exposure to inoculated flies. The first filial generation pupae and flies collected at different times during the experiments were all negative by q-RT-PCR. Of 1693 nycteribiid flies collected from a wild ERB colony in Mahune Cave, South Africa where the enzootic transmission of MARV occurs, only one (0.06%) tested positive for the presence of MARV RNA. Our findings seem to demonstrate that bat flies do not play a significant role in the transmission and enzootic maintenance of MARV. However, ERBs eat nycteribiid flies; thus, the mechanical transmission of the virus through the exposure of damaged mucous membranes and/or skin to flies engorged with contaminated blood cannot be ruled out.

Clinical efficacy and safety evaluation of favipiravir in treating patients with severe fever with thrombocytopenia syndrome

Background

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease with high mortality, however with no effective therapy available.

Methods

The effect of favipiravir (FPV) in treating SFTS was evaluated by an integrated analysis on data collected from a single-arm study (n=428), a surveillance study (n=2350) and published data from a randomized controlled trial study (n=145). A 1:1 propensity score matching was performed to include 780 patients: 390 received FPV and 390 received supportive therapy only. Case fatality rates (CFRs), clinical progress, and adverse effects were compared.

Findings

FPV treatment had significantly reduced CFR from 20.0% to 9.0% (odds ratio 0.38, 95% confidence interval 0.23-0.65), however showing heterogeneity when patients were grouped by age, onset-to-admission interval, initial viral load and therapy duration. The effect of FPV was significant only among patients aged ≤70 years, with onset-to-admission interval ≤5 days, therapy duration ≥5 days or baseline viral load ≤1 × 10⁶ copies/mL. Age-stratified analysis revealed no benefit in the aging group >70 years, regardless of their sex, onset-to-admission interval, therapy duration or baseline viral load. However, for both ≤60 and 60-70 years groups, therapy duration and baseline viral load differentially affected FPV therapy efficiency. Hyperuricemia and thrombocytopenia, as the major adverse response of FPV usage, were observed in >70 years patients.

Interpretation

FPV was safe in treating SFTS patients but showed no benefit for those aged >70 years. Instant FPV therapy could highly benefit SFTS patients aged 60-70 years.

Funding

China Natural Science Foundation (No. 81825019, 82073617 and 81722041) and China Mega-project for Infectious Diseases (2018ZX10713002 and 2015ZX09102022).

Potential drug development and therapeutic approaches for clinical intervention in COVID-19

While the vaccination is now available to many countries and will slowly dissipate to others, effective therapeutics for COVID-19 is still illusive. The SARS-CoV-2 pandemic has posed an unprecedented challenge to researchers, scientists, and clinicians and affected the wellbeing of millions of people worldwide. Since the beginning of the pandemic, a multitude of existing anti-viral, antibiotic, antimalarial, and anticancer drugs have been tested, and some have shown potency in the treatment and management of COVID-19, albeit others failed to leave any positive impact and a few also became controversial as they showed mixed clinical outcomes. In the present article, we have brought together some of the candidate therapeutic drugs being repurposed or used in the clinical trials and discussed their clinical efficacy and safety for COVID-19.

Conditions of Global Health Crisis Decision-Making-An Ethical Analysis

The circumstances of a public health emergency (PHE) shape reasoning and decision-making in ways that deviate from routine circumstances, where adherence to established values, principles, and methodologies is expected. Understanding what drives these deviations is critical to assessing their ethical consequences. In this paper we describe four conditions that influence decision-making during PHEs, in particular regarding the deployment and conduct of research on experimental or novel biomedical interventions. These four conditions are politicization, urgency, uncertainty, and fear. We argue that taken together these four conditions create pressure to address the most visible targets of immediate crisis events, driving emphasis on research and development of biomedical interventions. However, this emphasis raises ethical concerns regarding the extent to which attention to and investment in the underlying causes of PHEs, particularly impoverished global public health infrastructure, is diminished as a result.

Comparison and Evaluation of Real-Time Taqman PCR for Detection and Quantification of Ebolavirus

Given that ebolavirus causes severe and frequently lethal disease, its rapid and accurate detection using available and validated methods is essential for controlling infection. Real-time reverse-transcription PCR (RT-PCR) has proven to be an invaluable tool for ebolaviruses diagnostics. Many assays with different targets have been developed, but they have not been externally compared or validated, and limits of detection are not uniformly reported. Here we compared and evaluated the sensitivity, reproducibility and specificity of 23 in-house assays under the same conditions. Our results showed that these assays were highly gene- and species- specific when evaluated using in vitro RNA transcripts and viral RNA, and the potential limits of detection were uniformly reported ranging from 102 to 106 in vitro synthesized RNA transcripts copies perμL and 1-100 TCID50/mL. The comparison of these assays indicated that those targeting the more conservative NP gene could be the better option for EVD case definition and quantitative measurement because of its higher sensitivity for the same species. Our analysis could contribute to the standardization of ebolavirus detection and quantification assays, which can offer a better understanding of the meaning of results across laboratories and time points, as well as make them easy to implement, especially under outbreak conditions.

Metal doped fullerene complexes as promising drug delivery materials against COVID-19

An outbreak of respiratory disorder caused by coronavirus has been named as coronavirus infection 2019 (COVID-19). To find a specific treatment against this disease researchers are at the frontline. To cure COVID-19, favipiravir (FPV) has been reported as an effective drug based on its high recovery rate. Among nanomaterials, fullerene C60 has achieved enormous attention as a drug delivery vehicle due to its good bioavailability and low toxicity. Hence, in this work, we have investigated the potential of metal-doped fullerene as a drug carrier, based on DFT calculations by using M06-2X functional and 6-31G(d) basis set in water media. In this research electronic parameters and adsorption energy of FPV on interaction with metal-doped (Cr, Fe, and Ni) fullerene is studied. The charge transfer between drug and doped fullerene has been studied through electrophilicity indexes. The structural and electronic properties are explored in terms of adsorption energy through frontier molecular orbital (FMO) and density of state (DOS). It is observed that doping of fullerene C60 with Cr, Fe, and Ni metals significantly enhances the drug delivery rate and provides numerous advantages including controlled drug release at specific target sites which minimize the generic collection in vivo and reduce the side effects. Thusly, it is suggested that our designed metal-doped complexes might be efficient candidates as drug delivery materials for COVID-19 infection.

Transparent reporting of recruitment and informed consent approaches in clinical trials recruiting children with minor parents in sub-Saharan Africa: a secondary analysis based on a systematic review

BACKGROUND

Standardised checklists of items to be addressed in clinical study protocols and publications are promoting transparency in research. However, particular specifications for exceptional cases, such as children with minor parents are missing. This study aimed to examine the level of transparency regarding recruitment and informed consent approaches in publications of clinical trials recruiting children with minor parents in sub-Saharan Africa. We thereby focused particularly on the transparency about consenting persons (i.e. proxy decision-makers) and assessed the need to expand reporting guidelines for such exceptional cases.

METHODS

We conducted a secondary analysis of clinical trial publications previously identified through a systematic review. Multiple scientific databases were searched up to March 2019. Clinical trial publications addressing consent and potentially recruiting children with minor parents in sub-Saharan Africa were included. 44 of the in total 4382 screened articles met our inclusion criteria. A descriptive analysis was performed.

RESULTS

None of the included articles provided full evidence on whether any recruited children had minor parents and how consent was obtained for them. Four proxy decision-maker types were identified (parents; parents or guardians; guardians; or caregivers), with further descriptions provided rarely and mostly in referenced clinical trial registrations or protocols. Also, terminology describing proxy decision-makers was often used inconsistently.

CONCLUSIONS

Reporting the minimum maternal age alongside maternal data provided in baseline demographics can increase transparency on the recruitment of children with minor mothers. The CONSORT checklist should require clinical trial publications to state or reference exceptional informed consent procedures applied for special population groups. A standardized definition of proxy decision-maker types in international clinical trial guidelines would facilitate correct and transparent informed consent for children and children with minor parents.

STUDY REGISTRATION

CRD42018074220 .

COVID-19: Unmasking Emerging SARS-CoV-2 Variants, Vaccines and Therapeutic Strategies

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the etiological agent of the coronavirus disease 2019 (COVID-19) pandemic, which has been a topic of major concern for global human health. The challenge to restrain the COVID-19 pandemic is further compounded by the emergence of several SARS-CoV-2 variants viz. B.1.1.7 (Alpha), B.1.351 (Beta), P1 (Gamma) and B.1.617.2 (Delta), which show increased transmissibility and resistance towards vaccines and therapies. Importantly, there is convincing evidence of increased susceptibility to SARS-CoV-2 infection among individuals with dysregulated immune response and comorbidities. Herein, we provide a comprehensive perspective regarding vulnerability of SARS-CoV-2 infection in patients with underlying medical comorbidities. We discuss ongoing vaccine (mRNA, protein-based, viral vector-based, etc.) and therapeutic (monoclonal antibodies, small molecules, plasma therapy, etc.) modalities designed to curb the COVID-19 pandemic. We also discuss in detail, the challenges posed by different SARS-CoV-2 variants of concern (VOC) identified across the globe and their effects on therapeutic and prophylactic interventions.

Favipiravir treatment prolongs the survival in a lethal mouse model intracerebrally inoculated with Jamestown Canyon virus

Background

Jamestown Canyon virus (JCV) is a mosquito-borne orthobunyavirus that causes acute febrile illness, meningitis, and meningoencephalitis, primarily in North American adults. Currently, there are no available vaccines or specific treatments against JCV infections.

Methodology/Principal findings

The antiviral efficacy of favipiravir (FPV) against JCV infection was evaluated in vitro and in vivo in comparison with that of ribavirin (RBV) and 2’-fluoro-2’-deoxycytidine (2’-FdC). The in vitro inhibitory effect of these drugs on JCV replication was evaluated in Vero and Neuro-2a (N2A) cells. The efficacy of FPV in the treatment of JCV infection in vivo was evaluated in C57BL/6J mice inoculated intracerebrally with JCV, as per the survival, viral titers in the brain, and viral RNA load in the blood. The 90% inhibitory concentrations (IC₉₀) of FPV, RBV, and 2’-FdC were 41.0, 61.8, and 13.6 μM in Vero cells and 20.7, 25.8, and 8.8 μM in N2A cells, respectively. All mice infected with 1.0×10⁴ TCID₅₀ died or were sacrificed within 10 days post-infection (dpi) without treatment. However, mice treated with FPV for 5 days [initiated either 2 days prior to infection (−2 dpi–2 dpi) or on the day of infection (0 dpi–4 dpi)] survived significantly longer than control mice, administered with PBS (p = 0.025 and 0.011, respectively). Moreover, at 1 and 3 dpi, the virus titers in the brain were significantly lower in FPV-treated mice (0 dpi–4 dpi) versus PBS-treated mice (p = 0.002 for both 1 and 3 dpi).

Conclusions/Significance

Although the intracerebral inoculation route is thought to be a challenging way to evaluate drug efficacy, FPV inhibits the in vitro replication of JCV and prolongs the survival of mice intracerebrally inoculated with JCV. These results will enable the development of a specific antiviral treatment against JCV infections and establishment of an effective animal model.

Jamestown Canyon virus (JCV) is a mosquito-borne virus (arbovirus) classified into the California serogroup. JCV is distributed widely throughout North America and is considered one of the potentially re-emerging viruses due to the recent spurt in JCV cases in the region. JCV infection often leads to an acute febrile illness, meningitis, and meningoencephalitis mainly among adults. Currently, no antiviral therapy against JCV is approved. In this study, we evaluated the antiviral efficacy of favipiravir (FPV), ribavirin (RBV), and 2’-fluoro-2’-deoxycytidine (2’-FdC) against JCV infection in cultured cells and mice. As a result, FPV, RBV, and 2’-FdC effectively inhibited JCV replication in Vero and Neuro-2a cells. Furthermore, FPV delayed the onset of neurological symptoms in mice intracerebrally inoculated with JCV. Notably, although most patients infected with JCV do not present severe disease, neuroinvasive cases are not rare and may result in residual neurological sequelae such as persisting cognitive deficits. Therefore, this study contributes to the development of a specific antiviral treatment for patients with JCV infection.

Effectiveness and safety of favipiravir compared to supportive care in moderately to critically ill COVID-19 patients: a retrospective study with propensity score matching sensitivity analysis

INTRODUCTION

Favipiravir is a repurposed drug to treat coronavirus 2019 (COVID-19). Due to a lack of available real-world data, we assessed its effectiveness and safety in moderately to critically ill COVID-19 patients.

METHODS

This retrospective study was conducted in two public/specialty hospitals in Saudi Arabia. We included patients ≥18 years) admitted April-August 2020 with confirmed SARS-CoV-2 diagnosed by real-time polymerase chain reaction (RT-PCR) from nasopharyngeal swab. Patients received either favipiravir (1800 mg or 1600 mg twice daily loading dose, followed by 800 mg or 600 mg twice daily) or supportive-care treatment. Patients were excluded if they were outside the study period, classified as having a mild form of the disease per WHO criteria, or had an incomplete patient file. Kaplan-Meier (KM) models were used to estimate median time to discharge. Discharge ratios, progression to mechanical ventilation, and mortality outcomes were estimated across the severity spectrum using Cox proportional-hazards models. As a sensitivity analysis, we performed propensity score-matching (PSM) analysis.

RESULTS

Overall, median time to discharge was 10 days (95%CI = 9-10) in the favipiravir arm versus 15 days (95%CI = 14-16) in the supportive-care arm. The accelerated discharge benefit was seen across the COVID-19 spectrum of severity. The adjusted discharge ratio was 1.96 (95%CI = 1.56-2.46). Progression to mechanical ventilation was slower with favipiravir (HRadj = 0.10, 95%CI = 0.04-0.29). There was no significant effect on mortality (HRadj = 1.56, 95%CI = 0.73-3.36). There was a statistically non-significant trend toward worse outcomes in the critical category (HRadj = 2.80, 95%CI = 0.99-7.89). Age was an independent risk factor for mortality in mechanically ventilated patients. PSM analyses confirmed these findings.

CONCLUSION

Favipiravir was associated with clinical benefits, including accelerated discharge rate and less progression to mechanical ventilation; however, no overall mortality benefits were seen across the severity spectrum.

Drug-induced organ injury in coronavirus disease 2019 pharmacotherapy: Mechanisms and challenges in differential diagnosis and potential protective strategies

The world is currently facing an unprecedented pandemic caused by a newly recognized and highly pathogenic coronavirus disease 2019 (COVID-19; induced by SARS-CoV-2 virus), which is a severe and ongoing threat to global public health. Since COVID-19 was officially declared a pandemic by the World Health Organization in March 2020, several drug regimens have rapidly undergone clinical trials for the management of COVID-19. However, one of the major issues is drug-induced organ injury, which is a prominent clinical challenge. Unfortunately, most drugs used against COVID-19 are associated with adverse effects in different organs, such as the kidney, heart, and liver. These side effects are dangerous and, in some cases, they can be lethal. More importantly, organ injury is also a clinical manifestation of COVID-19 infection. These adverse reactions are increasingly recognized as outcomes of COVID-19 infection. Therefore, the differential diagnosis of drug-induced adverse effects from COVID-19-induced organ injury is a clinical complication. This review highlights the importance of drug-induced organ injury, its known mechanisms, and the potential therapeutic strategies in COVID-19 pharmacotherapy. We review the potential strategies for the differential diagnosis of drug-induced organ injury. This information can facilitate the development of therapeutic strategies, not only against COVID-19 but also for future outbreaks of other emerging infectious diseases.

Treatment of SARS-CoV-2 pneumonia with favipiravir: early results from the Ege University cohort, Turkey

Background/aim

The aim of this descriptive article is to share the experience in Ege University, Turkey with favipiravir in the treatment of severe SARS-CoV-2 pneumonia.

Materials and methods

This retrospective descriptive study included patients diagnosed with COVID-19 who presented with or developed severe pneumonia.

Results

Forty patients who completed a full course (at least 5 days) of favipiravir were included in the study. At baseline, 30 (75%) patients required treatment for respiratory distress. Thirty-three patients (82.5%) were discharged from the hospital with full recovery, 6 patients (15%) died and 1 case (2.5%) was still at the intensive care unit (ICU) when this paper was written.

Conclusion

This study provides relevant information for the treatment of COVID-19, suggesting that favipiravir was associated with significant clinical and laboratory improvements in the majority of the patients, is a safe drug with no serious side effects and would merit further investigation.

Flavonoids as Promising Antiviral Agents against SARS-CoV-2 Infection: A Mechanistic Review

A newly diagnosed coronavirus in 2019 (COVID-19) has affected all human activities since its discovery. Flavonoids commonly found in the human diet have attracted a lot of attention due to their remarkable biological activities. This paper provides a comprehensive review of the benefits of flavonoids in COVID-19 disease. Previously-reported effects of flavonoids on five RNA viruses with similar clinical manifestations and/or pharmacological treatments, including influenza, human immunodeficiency virus (HIV), severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), and Ebola, were considered. Flavonoids act via direct antiviral properties, where they inhibit different stages of the virus infective cycle and indirect effects when they modulate host responses to viral infection and subsequent complications. Flavonoids have shown antiviral activity via inhibition of viral protease, RNA polymerase, and mRNA, virus replication, and infectivity. The compounds were also effective for the regulation of interferons, pro-inflammatory cytokines, and sub-cellular inflammatory pathways such as nuclear factor-κB and Jun N-terminal kinases. Baicalin, quercetin and its derivatives, hesperidin, and catechins are the most studied flavonoids in this regard. In conclusion, dietary flavonoids are promising treatment options against COVID-19 infection; however, future investigations are recommended to assess the antiviral properties of these compounds on this disease.

Potential pharmacological strategies targeting the Niemann-Pick C1 receptor and Ebola virus glycoprotein interaction

Niemann-Pick C1 (NPC1) receptor is an intracellular protein located in late endosomes and lysosomes whose main function is to regulate intracellular cholesterol trafficking. Besides being postulated as necessary for the infection of highly pathogenic viruses in which the integrity of cholesterol transport is required, this protein also allows the entry of the Ebola virus (EBOV) into the host cells acting as an intracellular receptor. EBOV glycoprotein (EBOV-GP) interaction with NPC1 at the endosomal membrane triggers the release of the viral material into the host cell, starting the infective cycle. Disruption of the NPC1/EBOV-GP interaction could represent an attractive strategy for the development of drugs aimed at inhibiting viral entry and thus infection. Some of the today available EBOV inhibitors were proposed to interrupt this interaction, but molecular and structural details about their mode of action are still preliminary thus more efforts are needed to properly address these points. Here, we provide a critical discussion of the potential of NPC1 and its interaction with EBOV-GP as a therapeutic target for viral infections.

The 15-Months Clinical Experience of SARS-CoV-2: A Literature Review of Therapies and Adjuvants

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the virus responsible for the coronavirus disease of 2019 (COVID-19) that emerged in December 2019 in Wuhan, China, and rapidly spread worldwide, with a daily increase in confirmed cases and infection-related deaths. The World Health Organization declared a pandemic on the 11th of March 2020. COVID-19 presents flu-like symptoms that become severe in high-risk medically compromised subjects. The aim of this study was to perform an updated overview of the treatments and adjuvant protocols for COVID-19.

METHODS

A systematic literature search of databases was performed (MEDLINE PubMed, Google Scholar, UpToDate, Embase, and Web of Science) using the keywords: "COVID-19", "2019-nCoV", "coronavirus" and "SARS-CoV-2" (date range: 1 January 2019 to 31st October 2020), focused on clinical features and treatments.

RESULTS

The main treatments retrieved were antivirals, antimalarials, convalescent plasma, immunomodulators, corticosteroids, anticoagulants, and mesenchymal stem cells. Most of the described treatments may provide benefits to COVID-19 subjects, but no one protocol has definitively proven its efficacy.

CONCLUSIONS

While many efforts are being spent worldwide in research aimed at identifying early diagnostic methods and evidence-based effective treatments, mass vaccination is thought to be the best option against this disease in the near future.

Favipiravir for the treatment of patients with COVID-19: a systematic review and meta-analysis

BACKGROUND

Favipiravir possesses high utility for treating patients with COVID-19. However, research examining the efficacy and safety of favipiravir for patients with COVID-19 is limited.

METHODS

We conducted a systematic review of published studies reporting the efficacy of favipiravir against COVID-19. Two investigators independently searched PubMed, the Cochrane Database of Systematic Reviews, MedRxiv, and ClinicalTrials.gov (inception to September 2020) to identify eligible studies. A meta-analysis was performed to measure viral clearance and clinical improvement as the primary outcomes.

RESULTS

Among 11 eligible studies, 5 included a comparator group. Comparing to the comparator group, the favipiravir group exhibited significantly better viral clearance on day 7 after the initiation of treatment (odds ratio [OR] = 2.49, 95% confidence interval [CI] = 1.19-5.22), whereas no difference was noted on day 14 (OR = 2.19, 95% CI = 0.69-6.95). Although clinical improvement was significantly better in the favipiravir group on both days 7 and 14, the improvement was better on day 14 (OR = 3.03, 95% CI = 1.17-7.80) than on day 7 (OR = 1.60, 95% CI = 1.03-2.49). The estimated proportions of patients with viral clearance in the favipiravir arm on days 7 and 14 were 65.42 and 88.9%, respectively, versus 43.42 and 78.79%, respectively, in the comparator group. The estimated proportions of patients with clinical improvement on days 7 and 14 in the favipiravir group were 54.33 and 84.63%, respectively, compared with 34.40 and 65.77%, respectively, in the comparator group.

CONCLUSIONS

Favipiravir induces viral clearance by 7 days and contributes to clinical improvement within 14 days. The results indicated that favipiravir has strong possibility for treating COVID-19, especially in patients with mild-to-moderate illness. Additional well-designed studies, including examinations of the dose and duration of treatment, are crucial for reaching definitive conclusions.

Benefits of treatment with favipiravir in hospitalized patients for COVID-19: a retrospective observational case-control study

BACKGROUND

Although more than a year past since COVID-19 was defined, there is no specific treatment yet. Since COVID-19 management differs over time, it is hard to determine which therapy is more efficacious. In this study, we aimed to evaluate the efficacy of the regimen with Favipiravir (FPV) and determine if the timing of FPV addition offers any improvement.

METHODS

A retrospective observational case-controlled cohort study was performed between March and September 2020, including adults with COVID-19 in a single-center in Turkey. We categorized patients into age-sex matched three groups, group 1 (n = 48) and group 2 (n = 48) included patients treated with the combination of FPV plus Hydroxychloroquine (HQ) early and late, respectively. Group 3 (n = 48) consisted of patients on HQ monotherapy. In Group 2, if the respiratory or clinic condition had not improved sufficiently, FPV was added on or after day 3.

RESULTS

We found that starting FPV early had an impact on PCR negativity and the progression of the disease. 'No progression' was defined as the absence of a new finding in the control radiological examination and the absence of accompanying clinical deterioration. Also, the decrease in C-reactive protein (CRP) was greater in Group 1 than Group 3 (p < 0.001). However, we found that early initiation of FPV treatment did not have a positive effect on the estimated survival time.

CONCLUSIONS

According to this retrospective study results, we believe that for better clinical outcomes, FPV treatment should be started promptly to enhance antiviral effects and improve clinical outcomes.

Current Strategies of Antiviral Drug Discovery for COVID-19

SARS-CoV-2 belongs to the family of enveloped, single-strand RNA viruses known as Betacoronavirus in Coronaviridae, first reported late 2019 in China. It has since been circulating world-wide, causing the COVID-19 epidemic with high infectivity and fatality rates. As of the beginning of April 2021, pandemic SARS-CoV-2 has infected more than 130 million people and led to more than 2.84 million deaths. Given the severity of the epidemic, scientists from academia and industry are rushing to identify antiviral strategies to combat the disease. There are several strategies in antiviral drugs for coronaviruses including empirical testing of known antiviral drugs, large-scale phenotypic screening of compound libraries and target-based drug discovery. To date, an increasing number of drugs have been shown to have anti-coronavirus activities in vitro and in vivo, but only remdesivir and several neutralizing antibodies have been approved by the US FDA for treating COVID-19. However, remdesivir's clinical effects are controversial and new antiviral drugs are still urgently needed. We will discuss the current status of the drug discovery efforts against COVID-19 and potential future directions. With the ever-increasing movability of human population and globalization of world economy, emerging and reemerging viral infectious diseases seriously threaten public health. Particularly the past and ongoing outbreaks of coronaviruses cause respiratory, enteric, hepatic and neurological diseases in infected animals and human (Woo et al., 2009). The human coronavirus (HCoV) strains (HCoV-229E, HCoV-OC43, HCoV-NL63, and HCoV-HKU1) usually cause common cold with mild, self-limiting upper respiratory tract infections. By contrast, the emergence of three deadly human betacoronaviruses, middle east respiratory syndrome coronavirus (MERS) (Zaki et al., 2012), severe acute respiratory syndrome coronavirus (SARS-CoV) (Lee et al., 2003), the SARS-CoV-2 (Jin et al., 2020a) highlight the need to identify new treatment strategies for viral infections. SARS-CoV-2 is the etiological agent of COVID-19 disease named by World Health Organization (WHO) (Zhu N. et al., 2020). This disease manifests as either an asymptomatic infection or a mild to severe pneumonia. This pandemic disease causes extent morbidity and mortality in the whole world, especially regions out of China. Similar to SARS and MERS, the SARS CoV-2 genome encodes four structural proteins, sixteen non-structural proteins (nsp) and accessory proteins. The structural proteins include spike (S), envelope (E), membrane (M), nucleoprotein (N). The spike glycoprotein directly recognizes and engages cellular receptors during viral entry. The four non-structural proteins including papain-like protease (PLpro), 3-chymotrypsin-like protease (3CLpro), helicase, and RNA-dependent RNA polymerase (RdRp) are key enzymes involved in viral transcription and replication. The spike and the four key enzymes were considered attractive targets to develop antiviral agents (Zumla et al., 2016). The catalytic sites of the four enzymes of SARS-CoV2 share high similarities with SARS CoV and MERS in genomic sequences (Morse et al., 2020). Besides, the structures of the key drug-binding pockets are highly conserved among the three coronaviruses (Morse et al., 2020). Therefore, it follows naturally that existing anti-SARS-CoV and anti-MERS drugs targeting these enzymes can be repurposed for SARS-CoV-2. Based on previous studies in SARS-CoV and MERS-CoV, it is anticipated a number of therapeutics can be used to control or prevent emerging infectious disease COVID-19 (Li and de Clercq, 2020; Wang et al., 2020c; Ita, 2021), these include small-molecule drugs, peptides, and monoclonal antibodies. Given the urgency of the SARS-CoV-2 outbreak, here we discuss the discovery and development of new therapeutics for SARS-CoV-2 infection based on the strategies from which the new drugs are derived.

Evaluation by simulation of clinical trial designs for evaluation of treatment during a viral haemorrhagic fever outbreak

Background

Viral haemorrhagic fevers are characterized by irregular outbreaks with high mortality rate. Difficulties arise when implementing therapeutic trials in this context. The outbreak duration is hard to predict and can be short compared to delays of trial launch and number of subject needed (NSN) recruitment. Our objectives were to compare, using clinical trial simulation, different trial designs for experimental treatment evaluation in various outbreak scenarios.

Methods

Four type of designs were compared: fixed or group-sequential, each being single- or two-arm. The primary outcome was 14-day survival rate. For single-arm designs, results were compared to a pre-trial historical survival rate p_H. Treatments efficacy was evaluated by one-sided tests of proportion (fixed designs) and Whitehead triangular tests (group-sequential designs) with type-I-error = 0.025. Both survival rates in the control arm p_C and survival rate differences Δ (including 0) varied. Three specific cases were considered: “standard” (fixed p_C, reaching NSN for fixed designs and maximum sample size N_Max for group-sequential designs); “changing with time” (increased p_C over time); “stopping of recruitment” (epidemic ends). We calculated the proportion of simulated trials showing treatment efficacy, with K = 93,639 simulated trials to get a type-I-error PI_95% of [0.024;0.026].

Results

Under H₀ (Δ = 0), for the “standard” case, the type-I-error was maintained regardless of trial designs. For “changing with time” case, when p_C > p_H, type-I-error was inflated, and when p_C < p_H it decreased. Wrong conclusions were more often observed for single-arm designs due to an increase of Δ over time. Under H₁ (Δ = + 0.2), for the “standard” case, the power was similar between single- and two-arm designs when p_C = p_H. For “stopping of recruitment” case, single-arm performed better than two-arm designs, and fixed designs reported higher power than group-sequential designs. A web R-Shiny application was developed.

Conclusions

At an outbreak beginning, group-sequential two-arm trials should be preferred, as the infected cases number increases allowing to conduct a strong randomized control trial. Group-sequential designs allow early termination of trials in cases of harmful experimental treatment. After the epidemic peak, fixed single-arm design should be preferred, as the cases number decreases but this assumes a high level of confidence on the pre-trial historical survival rate.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12874-021-01287-w.

Strategy, Progress, and Challenges of Drug Repurposing for Efficient Antiviral Discovery

Emerging or re-emerging viruses are still major threats to public health. Prophylactic vaccines represent the most effective way to prevent virus infection; however, antivirals are more promising for those viruses against which vaccines are not effective enough or contemporarily unavailable. Because of the slow pace of novel antiviral discovery, the high disuse rates, and the substantial cost, repurposing of the well-characterized therapeutics, either approved or under investigation, is becoming an attractive strategy to identify the new directions to treat virus infections. In this review, we described recent progress in identifying broad-spectrum antivirals through drug repurposing. We defined the two major categories of the repurposed antivirals, direct-acting repurposed antivirals (DARA) and host-targeting repurposed antivirals (HTRA). Under each category, we summarized repurposed antivirals with potential broad-spectrum activity against a variety of viruses and discussed the possible mechanisms of action. Finally, we proposed the potential investigative directions of drug repurposing.

Clinical course of COVID-19 disease in immunosuppressed renal transplant patients

Background/aim

We aimed to identify clinical settings of renal transplant patients with COVID-19.

Materials and methods

In this retrospective study, we included kidney transplant inpatients with laboratory confirmed COVID-19 who had been discharged or had died by October 1st, 2020. Characteristics of the patients, including basal and last outpatient biochemical parameters were recorded. Discontinuation or dosage reduction of immunosuppressives and other treatment information was documented.

Results

Twenty patients were included in this study, of whom 18 were discharged and 2 died in hospital. The mean duration of hospitalization and follow-up were 9.7 ± 6.4 days and 4.5 ± 2.0 months, respectively. Fourteen patients (70%) were male and mean age was 48.0 ± 10.3 years. At admission, all had immunosuppression withdrawn and were started on methylprednisolone 16 mg/ day (50%) or dexamethasone (50%). Tacrolimus/m-TOR inhibitors were reduced by 50% and all antimetabolites were discontinued. Hemodialysis was needed for 10% of patients. Acute kidney injury was detected in 25% of the patients. With respect to hospitalization time and complications, there was no significant difference between patients who used dexamethasone and those who did not (P > 0.05). The discontinued immunosuppressives were resumed within 2 to 4 weeks after discharge according to the severity of disease. No rehospitalization or acute rejection was detected during the follow-up of the patients.

Conclusion

Renal transplant patients are considered a high risk group for COVID-19. It can be said that discontinuation or reducing dosages of immunosuppressives may be effective and safe in kidney transplant patients.

Evaluation of the frequency and intensity of favipiravir-associated yellow-green fluorescence in lunulae, hair, and face

BACKGROUND

We detected yellow-green fluorescence in the face, hair and lunulae of patients using favipiravir.

AIM

We evaluated the frequency and intensity of favipiravir-associated fluorescence.

PATIENTS/METHODS

The participants comprised patients who had taken at least a single dose of favipiravir and been examined no later than 30 days after the last dose. The gender, age, body mass index (BMI), Fitzpatrick's skin-type, hair color, N-acetylcysteine use, presence and the intensity of fluorescent reflection under Wood's light in the lunulae of the fingernails, hair, and the face were recorded.

RESULTS

There were 275 patients, 144 (52.4%) of whom were women. 165 (57.9%) had used treatment for a maximum of 5 days, 99 (34.7%) for 6-10 days, and 21 (7.4%) for more than ten days. Using more than 22 tablets of favipiravir increased the probability of detecting fluorescence in the lunulae by 6.72 (2.61-17.23) times. Using more than 28 tablets increased the risk of fluorescence in hair and the T-zone by 5.92 (2.43-14.71) and 2.88 (1.11-7.47) times, respectively. No relationship was found between the fluorescence intensity in any localization and the total dose. However, we determined a negative correlation between the elapsed time after the last dose and the fluorescence intensity in the lunulae and the T-zone (p=0.036; p=0.031; respectively). It was noted that BMI negatively correlated with the fluorescence intensity in the lunulae (p=0.001). Skin type was related to intensity for all localizations (p<0.001). Fluorescence was found in the lunulae with significantly less frequency in patients using N-acetylcysteine (p=0.040).

CONCLUSIONS

We must be aware of favipiravir-induced phototoxicity.

Favipiravir and Zanamivir Cleared Infection with Influenza B in a Severely Immunocompromised Child

A combination of favipiravir and zanamivir successfully cleared influenza B infection in a child who had undergone bone marrow transplant for X-linked severe combined immunodeficiency, with no recovery of T lymphocytes. Deep sequencing of viral samples illuminated the within-host dynamics of infection, demonstrating the effectiveness of favipiravir in this case.

Antiviral Evaluation of UV-4B and Interferon-Alpha Combination Regimens against Dengue Virus

Dengue virus (DENV) is a flavivirus associated with clinical manifestations ranging in severity from self-limiting dengue fever, to the potentially life threatening condition, severe dengue. There are currently no approved antiviral therapies for the treatment of DENV. Here, we evaluated the antiviral potential of four broad-spectrum antivirals, UV-4B, interferon-alpha (IFN), sofosbuvir (SOF), and favipiravir (FAV) against DENV serotype 2 as mono- and combination therapy in cell lines that are physiologically relevant to human infection. Cell lines derived from human liver (HUH-7), neurons (SK-N-MC), and skin (HFF-1) were infected with DENV and treated with UV-4B, IFN, SOF, or FAV. Viral supernatant was sampled daily and infectious viral burden was quantified by plaque assay on Vero cells. Drug effect on cell proliferation in uninfected and infected cells was also assessed. UV-4B inhibited DENV in HUH-7, SK-N-MC, and HFF-1 cells yielding EC₅₀ values of 23.75, 49.44, and 37.38 µM, respectively. Clinically achievable IFN concentrations substantially reduced viral burden in HUH-7 (EC₅₀ = 102.7 IU/mL), SK-N-MC (EC₅₀ = 86.59 IU/mL), and HFF-1 (EC₅₀ = 163.1 IU/mL) cells. SOF potently inhibited DENV in HUH-7 cells but failed to produce the same effect in SK-N-MC and HFF-1 cells. Finally, FAV provided minimal suppression in HUH-7 and SK-N-MC cells, but was ineffective in HFF-1 cells. The two most potent anti-DENV agents, UV-4B and IFN, were also assessed in combination. UV-4B + IFN treatment enhanced antiviral activity in HUH-7, SK-N-MC, and HFF-1 cells relative to monotherapy. Our results demonstrate the antiviral potential of UV-4B and IFN against DENV in multiple physiologically relevant cell types.

Favipiravir Does Not Inhibit Chikungunya Virus Replication in Mosquito Cells and Aedes aegypti Mosquitoes

Favipiravir (T-705) is a broad-spectrum antiviral drug that inhibits RNA viruses after intracellular conversion into its active form, T-705 ribofuranosyl 5'-triphosphate. We previously showed that T-705 is able to significantly inhibit the replication of chikungunya virus (CHIKV), an arbovirus transmitted by Aedes mosquitoes, in mammalian cells and in mouse models. In contrast, the effect of T-705 on CHIKV infection and replication in the mosquito vector is unknown. Since the antiviral activity of T-705 has been shown to be cell line-dependent, we studied here its antiviral efficacy in Aedes-derived mosquito cells and in Aedes aegypti mosquitoes. Interestingly, T-705 was devoid of anti-CHIKV activity in mosquito cells, despite being effective against CHIKV in Vero cells. By investigating the metabolic activation profile, we showed that, unlike Vero cells, mosquito cells were not able to convert T-705 into its active form. To explore whether alternative metabolization pathways might exist in vivo, Aedes aegypti mosquitoes were infected with CHIKV and administered T-705 via an artificial blood meal. Virus titrations of whole mosquitoes showed that T-705 was not able to reduce CHIKV infection in mosquitoes. Combined, these in vitro and in vivo data indicate that T-705 lacks antiviral activity in mosquitoes due to inadequate metabolic activation in this animal species.

Clinical effect and antiviral mechanism of T-705 in treating severe fever with thrombocytopenia syndrome

Severe fever with thrombocytopenia syndrome (SFTS) virus (SFTSV) is an emerging tick-borne virus with high fatality and an expanding endemic. Currently, effective anti-SFTSV intervention remains unavailable. Favipiravir (T-705) was recently reported to show in vitro and in animal model antiviral efficacy against SFTSV. Here, we conducted a single-blind, randomized controlled trial to assess the efficacy and safety of T-705 in treating SFTS (Chinese Clinical Trial Registry website, number ChiCTR1900023350). From May to August 2018, laboratory-confirmed SFTS patients were recruited from a designated hospital and randomly assigned to receive oral T-705 in combination with supportive care or supportive care only. Fatal outcome occurred in 9.5% (7/74) of T-705 treated patients and 18.3% (13/71) of controls (odds ratio, 0.466, 95% CI, 0.174-1.247). Cox regression showed a significant reduction in case fatality rate (CFR) with an adjusted hazard ratio of 0.366 (95% CI, 0.142-0.944). Among the low-viral load subgroup (RT-PCR cycle threshold ≥26), T-705 treatment significantly reduced CFR from 11.5 to 1.6% (P = 0.029), while no between-arm difference was observed in the high-viral load subgroup (RT-PCR cycle threshold <26). The T-705-treated group showed shorter viral clearance, lower incidence of hemorrhagic signs, and faster recovery of laboratory abnormities compared with the controls. The in vitro and animal experiments demonstrated that the antiviral efficacies of T-705 were proportionally induced by SFTSV mutation rates, particularly from two transition mutation types. The mutation analyses on T-705-treated serum samples disclosed a partially consistent mutagenesis pattern as those of the in vitro or animal experiments in reducing the SFTSV viral loads, further supporting the anti-SFTSV effect of T-705, especially for the low-viral loads.

Multicentre randomised double-blinded placebo-controlled trial of favipiravir in adults with mild COVID-19

INTRODUCTION

A novel coronavirus, designated SARS-CoV-2, caused an international outbreak of a respiratory illness, termed COVID-19 in December 2019. There is a lack of specific therapeutic agents based on evidence for this novel coronavirus infection; however, several medications have been evaluated as a potential therapy. Therapy is required to treat symptomatic patients and decrease the virus carriage duration to limit the communitytransmission.

METHODS AND ANALYSIS

We hypothesise that patients with mild COVID-19 treated with favipiravir will have a shorter duration of time to virus clearance than the control group. The primary outcome is to evaluate the effect of favipiravir on the timing of the PCR test conversion from positive to negative within 15 days after starting the medicine.Adults (>18 years, men or nonpregnant women, diagnosed with mild COVID-19 within 5 days of disease onset) are being recruited by physicians participating from the Ministry of National Guard Health Affairs and the Ministry of Health ethics committee approved primary healthcare centres. This double-blind, randomised trial comprises three significant parts: screening, treatment and a follow-up period. The treating physician and patients are blinded. Eligible participants are randomised in a 1:1 ratio to either the therapy group (favipiravir) or a control group (placebo) with 1800 mg by mouth two times per day for the first day, followed by 800 mg two times per day for 4-7 days. Serial nasopharyngeal/oropharyngeal swab samples are obtained on day 1 (5 days before therapy). On day5±1 day, 10±1 day, 15±2 days, extra nasopharyngeal/oropharyngeal PCR COVID-19 samples are requested.The primary analysis population for evaluating both the efficacy and safety outcomes will be a modified intention to treat population. Anticipating a 10% dropout rate, we expect to recruit 288 subjects per arm. The results assume that the hazard ratio is constant throughout the study and that the Cox proportional hazard regression is used to analyse the data.

ETHICS AND DISSEMINATION

The study was approved by the King Abdullah International Medical Research Centre Institutional Review Board (28 April 2020) and the Ministry of Health Institutional Review Board (1 July 2020). Protocol details and any amendments will be reported to https://clinicaltrials.gov/ct2/show/NCT04464408. The results will be published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

National Clinical Trial Registry (NCT04464408).

Broad-Spectrum Antiviral Strategies and Nucleoside Analogues

The emergence or re-emergence of viruses with epidemic and/or pandemic potential, such as Ebola, Zika, Middle East Respiratory Syndrome (MERS-CoV), Severe Acute Respiratory Syndrome Coronavirus 1 and 2 (SARS and SARS-CoV-2) viruses, or new strains of influenza represents significant human health threats due to the absence of available treatments. Vaccines represent a key answer to control these viruses. However, in the case of a public health emergency, vaccine development, safety, and partial efficacy concerns may hinder their prompt deployment. Thus, developing broad-spectrum antiviral molecules for a fast response is essential to face an outbreak crisis as well as for bioweapon countermeasures. So far, broad-spectrum antivirals include two main categories: the family of drugs targeting the host-cell machinery essential for virus infection and replication, and the family of drugs directly targeting viruses. Among the molecules directly targeting viruses, nucleoside analogues form an essential class of broad-spectrum antiviral drugs. In this review, we will discuss the interest for broad-spectrum antiviral strategies and their limitations, with an emphasis on virus-targeted, broad-spectrum, antiviral nucleoside analogues and their mechanisms of action.

Lassa fever outcomes and prognostic factors in Nigeria (LASCOPE): a prospective cohort study

Background

Lassa fever is a viral haemorrhagic fever endemic in parts of west Africa. New treatments are needed to decrease mortality, but pretrial reference data on the disease characteristics are scarce. We aimed to document baseline characteristics and outcomes for patients hospitalised with Lassa fever in Nigeria.

Methods

We did a prospective cohort study (LASCOPE) at the Federal Medical Centre in Owo, Nigeria. All patients admitted with confirmed Lassa fever were invited to participate and asked to give informed consent. Patients of all ages, including newborn infants, were eligible for inclusion, as were pregnant women. All participants received standard supportive care and intravenous ribavirin according to Nigeria Centre for Disease Control guidelines and underwent systematic biological monitoring for 30 days. Patients' characteristics, care received, mortality, and associated factors were recorded using standard WHO forms. We used univariable and multivariable logistic regression models to investigate an association between baseline characteristics and mortality at day 30.

Findings

Between April 5, 2018, and March 15, 2020, 534 patients with confirmed Lassa fever were admitted to hospital, of whom 510 (96%) gave consent and were included in the analysis. The cohort included 258 (51%) male patients, 252 (49%) female patients, 426 (84%) adults, and 84 (16%) children (younger than 18 years). The median time between first symptoms and hospital admission was 8 days (IQR 7–13). At baseline, 176 (38%) of 466 patients had a Lassa fever RT-PCR cycle threshold (Ct) lower than 30. From admission to end of follow-up, 120 (25%) of 484 reached a National Early Warning Score (second version; NEWS2) of 7 or higher, 67 (14%) of 495 reached a Kidney Disease–Improving Global Outcome (KDIGO) stage of 2 or higher, and 41 (8%) of 510 underwent dialysis. All patients received ribavirin for a median of 10 days (IQR 9–13). 62 (12%) patients died (57 [13%] adults and five [6%] children). The median time to death was 3 days (1–6). The baseline factors independently associated with mortality were the following: age 45 years or older (adjusted odds ratio 16·30, 95% CI 5·31–50·30), NEWS2 of 7 or higher (4·79, 1·75–13·10), KDIGO grade 2 or higher (7·52, 2·66–21·20), plasma alanine aminotransferase 3 or more times the upper limit of normal (4·96, 1·69–14·60), and Lassa fever RT-PCR Ct value lower than 30 (4·65, 1·50–14·50).

Interpretation

Our findings comprehensively document clinical and biological characteristics of patients with Lassa fever and their relationship with mortality, providing prospective estimates that could be useful for designing future therapeutic trials. Such trials comparing new Lassa fever treatments to a standard of care should take no more than 15% as the reference mortality rate and consider adopting a combination of mortality and need for dialysis as the primary endpoint.

Funding

Institut National de la Santé et de la Recherche Médicale, University of Oxford, EU, UK Department for International Development, Wellcome Trust, French Ministry of Foreign Affairs, Agence Nationale de Recherches sur le SIDA et les hépatites virales, French National Research Institute for Sustainable Development.

Early control of viral load by favipiravir promotes survival to Ebola virus challenge and prevents cytokine storm in non-human primates

Ebola virus has been responsible for two major epidemics over the last several years and there has been a strong effort to find potential treatments that can improve the disease outcome. Antiviral favipiravir was thus tested on non-human primates infected with Ebola virus. Half of the treated animals survived the Ebola virus challenge, whereas the infection was fully lethal for the untreated ones. Moreover, the treated animals that did not survive died later than the controls. We evaluated the hematological, virological, biochemical, and immunological parameters of the animals and performed proteomic analysis at various timepoints of the disease. The viral load strongly correlated with dysregulation of the biological functions involved in pathogenesis, notably the inflammatory response, hemostatic functions, and response to stress. Thus, the management of viral replication in Ebola virus disease is of crucial importance in preventing the immunopathogenic disorders and septic-like shock syndrome generally observed in Ebola virus-infected patients.

Ebola virus was responsible for several epidemics in the recent years and is now considered as a major public health concern in Central and West African countries. We and others demonstrated that pathogenic events observed during Ebola virus disease are linked to a deleterious immune response. However, the mechanisms implicated are not fully understood. Here, we studied immune responses depending on the viral loads observed in infected cynomolgus monkeys. An antiviral treatment allowed the reduction of viral load in some animals and we observed that these animals did not experience deleterious immune response and the loss of hemostasis. The release of pathogen-associated molecular patterns may thus be limited by the inhibition of viral replication, avoiding the overstimulation of the immune system and consequently the pathogenic events observed in Ebola virus disease.

Favipiravir antiviral efficacy against SARS-CoV-2 in a hamster model

Despite no or limited pre-clinical evidence, repurposed drugs are massively evaluated in clinical trials to palliate the lack of antiviral molecules against SARS-CoV-2. Here we use a Syrian hamster model to assess the antiviral efficacy of favipiravir, understand its mechanism of action and determine its pharmacokinetics. When treatment is initiated before or simultaneously to infection, favipiravir has a strong dose effect, leading to reduction of infectious titers in lungs and clinical alleviation of the disease. Antiviral effect of favipiravir correlates with incorporation of a large number of mutations into viral genomes and decrease of viral infectivity. Antiviral efficacy is achieved with plasma drug exposure comparable with those previously found during human clinical trials. Notably, the highest dose of favipiravir tested is associated with signs of toxicity in animals. Thereby, pharmacokinetic and tolerance studies are required to determine whether similar effects can be safely achieved in humans.

Potential therapeutic agents to COVID-19: An update review on antiviral therapy, immunotherapy, and cell therapy

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in Wuhan, China, in December 2020 and coronavirus disease 19 (COVID-19) was later announced as pandemic by the World Health Organization (WHO). Since then, several studies have been conducted on the prevention and treatment of COVID-19 by potential vaccines and drugs. Although, the governments and global population have been attracted by some vaccine production projects, the presence of SARS-CoV-2-specific antiviral drugs would be an urge necessity in parallel with the efficient preventive vaccines. Various nonspecific drugs produced previously against other bacterial, viral, and parasite infections were recently evaluated for treating patients with COVID-19. In addition to therapeutic properties of these anti-COVID-19 compounds, some adverse effects were observed in different human organs as well. Not only several attentions were paid to antiviral therapy and treatment of COVID-19, but also nanomedicine, immunotherapy, and cell therapy were conducted against this viral infection. In this review study, we planned to introduce the present and potential future treatment strategies against COVID-19 and define the advantages and disadvantages of each treatment strategy.

Safety and efficacy of Favipiravir in moderate to severe SARS-CoV-2 pneumonia

BACKGROUND

We examined the safety and efficacy of a treatment protocol containing Favipiravir for the treatment of SARS-CoV-2.

METHODS

We did a multicenter randomized open-labeled clinical trial on moderate to severe cases infections of SARS-CoV-2. Patients with typical ground glass appearance on chest computerized tomography scan (CT scan) and oxygen saturation (SpO₂) of less than 93% were enrolled. They were randomly allocated into Favipiravir (1.6 gr loading, 1.8 gr daily) and Lopinavir/Ritonavir (800/200 mg daily) treatment regimens in addition to standard care. In-hospital mortality, ICU admission, intubation, time to clinical recovery, changes in daily SpO₂ after 5 min discontinuation of supplemental oxygen, and length of hospital stay were quantified and compared in the two groups.

RESULTS

380 patients were randomly allocated into Favipiravir (193) and Lopinavir/Ritonavir (187) groups in 13 centers. The number of deaths, intubations, and ICU admissions were not significantly different (26, 27, 31 and 21, 17, 25 respectively). Mean hospital stay was also not different (7.9 days [SD = 6] in the Favipiravir and 8.1 [SD = 6.5] days in Lopinavir/Ritonavir groups) (p = 0.61). Time to clinical recovery in the Favipiravir group was similar to Lopinavir/Ritonavir group (HR = 0.94, 95% CI 0.75 - 1.17) and likewise the changes in the daily SpO₂ after discontinuation of supplemental oxygen (p = 0.46) CONCLUSION: Adding Favipiravir to the treatment protocol did not reduce the number of ICU admissions or intubations or In-hospital mortality compared to Lopinavir/Ritonavir regimen. It also did not shorten time to clinical recovery and length of hospital stay.

Trends and strategies to combat viral infections: A review on FDA approved antiviral drugs

The infectious microscopic viruses invade living cells to reproduce themselves, and causes chronic infections such as HIV/AIDS, hepatitis B and C, flu, etc. in humans which may lead to death if not treated. Different strategies have been utilized to develop new and superior antiviral drugs to counter the viral infections. The FDA approval of HIV nucleoside reverse transcriptase inhibitor, zidovudine in 1987 boosted the development of antiviral agents against different viruses. Currently, there are a number of combination drugs developed against various viral infections to arrest the activity of same or different viral macromolecules at multiple stages of its life cycle; among which majority are targeted to interfere with the replication of viral genome. Besides these, other type of antiviral molecules includes entry inhibitors, integrase inhibitors, protease inhibitors, interferons, immunomodulators, etc. The antiviral drugs can be toxic to human cells, particularly in case of administration of combination drugs, and on the other hand viruses can grow resistant to the antiviral drugs. Furthermore, emergence of new viruses like Ebola, coronaviruses (SARS-CoV, SARS-CoV-2) emphasizes the need for more innovative strategies to develop better antiviral drugs to fight the existing and the emerging viral infections. Hence, we reviewed the strategic enhancements in developing antiviral drugs for the treatment of different viral infections over the years.

Developing therapeutic approaches for twenty-first-century emerging infectious viral diseases

The twenty-first century has already recorded more than ten major epidemic or pandemic virus emergence events, including the ongoing and devastating coronavirus disease 2019 (COVID-19) pandemic. As viral disease emergence is expected to accelerate, these data dictate a need for proactive approaches to develop broadly active family-specific and cross-family therapeutics for use in future disease outbreaks. Emphasis should focus not only on the development of broad-spectrum small-molecule and antibody direct-acting antivirals, but also on host-factor therapeutics, including repurposing previously approved or in-pipeline drugs. Another new class of therapeutics with great antiviral therapeutic potential is RNA-based therapeutics. Rather than only focusing on known risks, dedicated efforts must be made toward pre-emptive research focused on outbreak-prone virus families, ultimately offering a strategy to shorten the gap between outbreak and response. Emphasis should also focus on orally available drugs for outpatient use, if possible, and on identifying combination therapies that combat viral and immune-mediated pathologies, extend the effectiveness of therapeutic windows and reduce drug resistance. While such an undertaking will require new vision, dedicated funding and private, federal and academic partnerships, this approach offers hope that global populations need never experience future pandemics such as COVID-19.

Respiratory delivery of favipiravir-tocilizumab combination through mucoadhesive protein-lipidic nanovesicles: prospective therapeutics against COVID-19

Coronavirus disease 19 (COVID-19) is the prime global health concern of the year 2020. Infecting more than 112 million individuals so far, this pandemic has already reported more than 2.4 million deaths around the world. With such high infectivity and mortality, effective treatment intervention is the need of the hour. The integration of medical science with nanotechnology may solve the current problem by exploring collective benefits. In this manuscript, we theoretically proposed the duo-combination of an approved antiviral i.e. favipiravir along with an immunomodulator i.e. tocilizumab loaded in protein-lipid nanovesicles as an effective anti-COVID-19 therapeutic. This proposed nanomedicine delivered through the respiratory mode may enhance the effectiveness of the antiviral and help in restricting the virus and associated complications, utilizing both anti-viral activity and immunomodulation in COVID-19 patients. This proposed nanomedicine could be an effective treatment modality for the severe acute respiratory syndrome- coronavirus-2 (SARS-CoV-2) infected patients.

Prevalence of Foreign Body Aspiration in Children in a Tertiary Care Hospital

Introduction:

Foreign body aspiration is a common problem in children with significant mortality and morbidity. This study aims to determine the prevalence of foreign body aspiration in children in a tertiary care hospital of Nepal.

Methods:

A descriptive cross-sectional study was conducted at Tribhuvan University Teaching Hospital from April 2010 to March 2016 after obtaining ethical approval from Institutional Review Committee (Reference number- 08(6-11)E277/78). All children of age up to 15 years with suspected foreign body aspiration were included. The data was collected from the medical record section and entered in Microsoft Excel. The descriptive statistical analysis was performed.

Results:

A total of 26,294 patients were included in the study. The prevalence of foreign body aspiration in children was found to be 98 (0.37%). On rigid bronchoscopy, 82 patients (83.6%) were confirmed to have a foreign body in the airway. The peak incidence of foreign body aspiration was seen in patients of age group one to two years. The commonest foreign body in the airway was a peanut.

Conclusions:

The prevalence of foreign body aspiration in children was low, which is similar to other studies. Foreign body aspiration may lead to dreadful complications. Therefore, both the clinicians and the public need to be cautious about it.

South American Hemorrhagic Fevers: A summary for clinicians

OBJECTIVES

This article is one of a series on acute, severe diseases of humans caused by emerging viruses for which there are no or limited licensed medical countermeasures. We approached this summary on South American Hemorrhagic Fevers (SAHF) from a clinical perspective that focuses on pathogenesis, clinical features, and diagnostics with an emphasis on therapies and vaccines that have demonstrated potential for use in an emergency situation through their evaluation in nonhuman primates (NHPs) and/or in humans.

METHODS

A standardized literature review was conducted on the clinical, pathological, vaccine, and treatment factors for SAHF as a group and for each individual virus/disease.

RESULTS

We identified 2 treatments and 1 vaccine platform that have demonstrated potential benefit for treating or preventing infection in humans and 4 other potential treatments currently under investigation.

CONCLUSION

We provide succinct summaries of these countermeasures to give the busy clinician a head start in reviewing the literature if faced with a patient with South American Hemorrhagic Fever. We also provide links to other authoritative sources of information.

Molecular Mechanism of Action of Repurposed Drugs and Traditional Chinese Medicine Used for the Treatment of Patients Infected With COVID-19: A Systematic Scoping Review

Background: The emergence of COVID-19 as a pandemic has resulted in the need for urgent development of vaccines and drugs and the conduction of clinical trials to fight the outbreak. Because of the time constraints associated with the development of vaccines and effective drugs, drug repurposing and other alternative treatment methods have been used to treat patients that have been infected by the SARS-CoV-2 virus and have acquired COVID-19. Objective: The objective of this systematic scoping review is to provide an overview of the molecular mechanism of action of repurposed drugs or alternative treatment medicines used to attenuate COVID-19 disease. Method: The research articles or gray literature, including theses, government reports, and official news online, were identified from four databases and one search engine. The full content of a total of 160 articles that fulfilled our inclusion criteria was analyzed and information about six drugs (ritonavir, lopinavir, oseltamivir, remdesivir, favipiravir, and chloroquine) and four Traditional Chinese Medicines (Shuang Huang Lian Kou Fu Ye, TCM combination of Bu Huan Jin Zheng Qi San and Da Yuan Yin, Xue Bi Jing Injection, and Qing Fei Pai Du Tang) was extracted. Results: All of the repurposed drugs and complementary medicine that have been used for the treatment of COVID-19 depend on the ability of the drug to inhibit the proliferation of the SARS-CoV-2 virus by binding to enzyme active sites, viral chain termination, or triggering of the molecular pathway, whereas Traditional Chinese Medicine plays a pivotal role in triggering the inflammation pathway, such as the neuraminidase blocker, to fight the SARS-CoV-2 virus.

In Silico Study of Coumarins and Quinolines Derivatives as Potent Inhibitors of SARS-CoV-2 Main Protease

The pandemic that started in Wuhan (China) in 2019 has caused a large number of deaths, and infected people around the world due to the absence of effective therapy against coronavirus 2 of the severe acute respiratory syndrome (SARS-CoV-2). Viral maturation requires the activity of the main viral protease (Mpro), so its inhibition stops the progress of the disease. To evaluate possible inhibitors, a computational model of the SARS-CoV-2 enzyme Mpro was constructed in complex with 26 synthetic ligands derived from coumarins and quinolines. Analysis of simulations of molecular dynamics and molecular docking of the models show a high affinity for the enzyme (∆E binding between -5.1 and 7.1 kcal mol-1). The six compounds with the highest affinity show K d between 6.26 × 10-6 and 17.2 × 10-6, with binding affinity between -20 and -25 kcal mol-1, with ligand efficiency less than 0.3 associated with possible inhibitory candidates. In addition to the high affinity of these compounds for SARS-CoV-2 Mpro, low toxicity is expected considering the Lipinski, Veber and Pfizer rules. Therefore, this novel study provides candidate inhibitors that would allow experimental studies which can lead to the development of new treatments for SARS-CoV-2.

Combination Regimens of Favipiravir Plus Interferon Alpha Inhibit Chikungunya Virus Replication in Clinically Relevant Human Cell Lines

Chikungunya virus (CHIKV) is an alphavirus associated with a broad tissue tropism for which no antivirals or vaccines are approved. This study evaluated the antiviral potential of favipiravir (FAV), interferon-alpha (IFN), and ribavirin (RBV) against CHIKV as mono- and combination-therapy in cell lines that are clinically relevant to human infection. Cells derived from human connective tissue (HT-1080), neurons (SK-N-MC), and skin (HFF-1) were infected with CHIKV and treated with different concentrations of FAV, IFN, or RBV. Viral supernatant was sampled daily and the burden was quantified by plaque assay on Vero cells. FAV and IFN were the most effective against CHIKV on various cell lines, suppressing the viral burden at clinically achievable concentrations; although the degree of antiviral activity was heavily influenced by cell type. RBV was not effective and demonstrated substantial toxicity, indicating that it is not a feasible candidate for CHIKV. The combination of FAV and IFN was then assessed on all cell lines. Combination therapy enhanced antiviral activity in HT-1080 and SK-N-MC cells, but not in HFF-1 cells. We developed a pharmacokinetic/pharmacodynamic model that described the viral burden and inhibitory antiviral effect. Simulations from this model predicted clinically relevant concentrations of FAV plus IFN completely suppressed CHIKV replication in HT-1080 cells, and considerably slowed down the rate of viral replication in SK-N-MC cells. The model predicted substantial inhibition of viral replication by clinical IFN regimens in HFF-1 cells. Our results highlight the antiviral potential of FAV and IFN combination regimens against CHIKV in clinically relevant cell types.

SARS-CoV-2: From the pathogenesis to potential anti-viral treatments

Introduction

The world is witnessing the spread of one of the members of Coronaviruses (CoVs) family, called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the 21st century. Considering the short time spent after its prevalence, limited information is known about the effect of the virus mechanism on different organs of the body; meanwhile the lack of specific treatment and vaccine for this virus has exposed millions of people to a big challenge.

Areas covered

The review article aims to describe the general and particular characteristics of CoVs, their classification, genome structure, host cell infection, cytokine storm, anti-viral treatments, and inhibition of COVID-19-related ER-mitochondrial stress. In addition, it refers to drugs such as Chloroquine/Hydroxychloroquine, Lopinavir/Ritonavir, darunavir, ribavirin, remdesivir, and favipiravir, which have undergone clinical trials for coronavirus disease 2019 (COVID-19) treatment. This analysis was derived from an extensive scientific literature search including Pubmed, ScienceDirect, and Google Scholar performed.

Expert opinion

The effectiveness rate and complications of these drugs can reveal new insights into the potential therapeutic goals for the disease. Moreover, lifestyle change can effectively prevent SARS-CoV-2 infection.

Mechanistic insight into anti-COVID-19 drugs: recent trends and advancements

The Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2) has been established now to be a deadly disease afflicting the whole world with worst consequences on healthcare, economy and day-to-day life activities. Being a communicable disease, which is highly pathogenic in humans, causing cough, throat infection, breathing problems, high fever, muscle pain, and may lead to death in some cases especially those having other comorbid conditions such as heart or kidney problems, and diabetes. Finding an appropriate drug and vaccine candidate against coronavirus disease (COVID-19) remains an ultimate and immediate goal for the global scientific community. Based on previous studies in the literature on SARS-CoV infection, there are a number of drugs that may inhibit the replication of SARS-CoV-2 and its infection. Such drugs comprise of inhibitors of Angiotensin-Converting Enzyme 2 (ACE2), transmembrane Serine Protease 2 (TMPRSS2), nonstructural protein 3C-like protease, nonstructural RNA-dependent RNA polymerase (RdRp) and many more. The antiviral drugs such as chloroquine and hydroxychloroquine, lopinavir and ritonavir as inhibitors for HIV protease, nucleotide analogue remdesivir, and broad-spectrum antiviral drugs are available to treat the SARS-CoV-2-infected patients. Therefore, this review article is planned to gain insight into the mechanism for blocking the entry of SARS-CoV-2, its validation, other inhibition mechanisms, and development of therapeutic drugs and vaccines against SARS-CoV-2.

Review of Ebola virus disease in children - how far have we come?

Ebola virus (EBOV) causes an extremely contagious viral haemorrhagic fever associated with high mortality. While, historically, children have represented a small number of total cases of Ebolavirus disease (EVD), in recent outbreaks up to a quarter of cases have been in children. They pose unique challenges in clinical management and infection prevention and control. In this review of paediatric EVD, the epidemiology of past EVD outbreaks with specific focus on children is discussed, the clinical manifestations and laboratory findings are described and key developments in clinical management including specific topics such as viral persistence and breastfeeding while considering unique psychosocial and anthropological considerations for paediatric care including of survivors and orphans and the stigma they face are discussed. In addition to summarising the literature, perspectives based on the authors' experience of EVD outbreaks in the Democratic Republic of the Congo (DRC) are described.Abbreviations: ARDS: acute respiratory distress syndrome; aOR: adjusted odds ratio; ALT: alanine transferase; ALIMA: Alliance for International Medical Action; AST: aspartate transaminase; BUN: blood urea nitrogen; CNS: central nervous system; CUBE: chambre d'urgence biosécurisée pour épidémie; COVID-19: coronavirus disease 2019; C_t: cycle threshold; DRC: Democratic Republic of Congo; ETC: ebola treatment centre; ETU: ebola treatment unit; EBOV: ebola virus; EVD: ebolavirus disease; FEAST: fluid expansion as supportive therapy; GP: glycoprotein; IV: intravenous; MEURI: monitored emergency use of unregistered interventions; NETEC: National Ebola Training and Education Centre; NP: nucleoprotein; ORS: oral rehydration solution; PALM: Pamoja Tulinde Maisha; PREVAIL: Partnership for Research on Ebola Virus in Liberia; PPE: personal protective equipment; PCR: polymerase chain reaction; PEP: post-exposure prophylaxis; RDTs: rapid diagnostic tests; RT: reverse transcriptase; RNA: ribonucleic acid; UNICEF: United Nations International Children's Emergency Fund; USA: United States of America; WHO: World Health Organization.

Favipiravir in Therapy of Viral Infections

Favipiravir (FPV) is a novel antiviral drug acting as a competitive inhibitor of RNA-dependent RNA polymerase (RdRp), preventing viral transcription and replication. FPV was approved in Japan in 2014 for therapy of influenza unresponsive to standard antiviral therapies. FPV was also used in the therapy of Ebola virus disease (EVD) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. In this review, we discuss the mechanisms of action, pharmacokinetic parameters, toxicity, and adverse effects of FPV, as well as clinical studies evaluating the use of FPV in the therapy of influenza virus (IV) infection, EVD, and SARS-CoV-2 infection, along with its effectiveness in treating other human RNA infections.

Analysis of an Ebola virus disease survivor whose host and viral markers were predictive of death indicates the effectiveness of medical countermeasures and supportive care

BACKGROUND

Ebola virus disease (EVD) is an often-fatal infection where the effectiveness of medical countermeasures is uncertain. During the West African outbreak (2013-2016), several patients were treated with different types of anti-viral therapies including monoclonal antibody-based cocktails that had the potential to neutralise Ebola virus (EBOV). However, at the time, the efficacy of these therapies was uncertain. Given the scale of the outbreak, several clinical phenotypes came to the forefront including the ability of the same virus to cause recrudescence in the same patient-perhaps through persisting in immune privileged sites. Several key questions remained including establishing if monoclonal antibody therapy was effective in humans with severe EVD, whether virus escape mutants were selected during treatment, and what is the potential mechanism(s) of persistence. This was made possible through longitudinal samples taken from a UK patient with EVD.

METHODS

Several different sample types, plasma and cerebrospinal fluid, were collected and sequenced using Illumina-based RNAseq. Sequence reads were mapped both to EBOV and the human genome and differential gene expression analysis used to identify changes in the abundance of gene transcripts as infection progressed. Digital Cell Quantitation analysis was used to predict the immune phenotype in samples derived from blood.

RESULTS

The findings were compared to equivalent data from West African patients. The study found that both virus and host markers were predictive of a fatal outcome. This suggested that the extensive supportive care, and most likely the application of the medical countermeasure ZMab (a monoclonal antibody cocktail), contributed to survival of the UK patient. The switch from progression to a 'fatal' outcome to a 'survival' outcome could be seen in both the viral and host markers. The UK patient also suffered a recrudescence infection 10 months after the initial infection. Analysis of the sequencing data indicated that the virus entered a period of reduced or minimal replication, rather than other potential mechanisms of persistence-such as defective interfering genomes.

CONCLUSIONS

The data showed that comprehensive supportive care and the application of medical countermeasures are worth pursuing despite an initial unfavourable prognosis.

Lassa viral dynamics in non-human primates treated with favipiravir or ribavirin

Lassa fever is an haemorrhagic fever caused by Lassa virus (LASV). There is no vaccine approved against LASV and the only recommended antiviral treatment relies on ribavirin, despite limited evidence of efficacy. Recently, the nucleotide analogue favipiravir showed a high antiviral efficacy, with 100% survival obtained in an otherwise fully lethal non-human primate (NHP) model of Lassa fever. However the mechanism of action of the drug is not known and the absence of pharmacokinetic data limits the translation of these results to the human setting. Here we aimed to better understand the antiviral effect of favipiravir by developping the first mathematical model recapitulating Lassa viral dynamics and treatment. We analyzed the viral dynamics in 24 NHPs left untreated or treated with ribavirin or favipiravir, and we put the results in perspective with those obtained with the same drugs in the context of Ebola infection. Our model estimates favipiravir EC50 in vivo to 2.89 μg.mL-1, which is much lower than what was found against Ebola virus. The main mechanism of action of favipiravir was to decrease virus infectivity, with an efficacy of 91% at the highest dose. Based on our knowledge acquired on the drug pharmacokinetics in humans, our model predicts that favipiravir doses larger than 1200 mg twice a day should have the capability to strongly reduce the production infectious virus and provide a milestone towards a future use in humans.