Antivirals for COVID-19: A critical review.

No specific drugs have been approved for coronavirus disease 2019 (COVID-19) to date as the development of antivirals usually requires time. Therefore, assessment and use of currently available antiviral drugs is critical for a timely response to the current pandemic. Here, we have reviewed anti-SARS-CoV-2 potencies of available antiviral drug groups such as fusion inhibitors, protease inhibitors, neuraminidase inhibitors, and M2 ion-channel protein blockers. Although clinical trials to assess the efficacy of these antivirals are ongoing, this review highlights important information including docking and modeling analyses, in vitro studies, as well as results from clinical uses of these antivirals against COVID-19 pandemic.

Need of booster vaccine doses to counteract the emergence of SARS-CoV-2 variants in the context of the Omicron variant and increasing COVID-19 cases: An update.

The emergence of different variants of SARS-CoV-2, including the Omicron (B.1.1.529) variant in November 2021, has resulted in a continuous major health concern at a global scale. Presently, the Omicron variant has spread very rapidly worldwide within a short time period. As the most mutated variant of SARS-CoV-2, Omicron has instilled serious uncertainties on the effectiveness of humoral adaptive immunity generated by COVID-19 vaccination or an active viral infection as well as the protection provided by antibody-based immunotherapies. Amidst such high public health concerns, the need to carry out booster vaccination has been emphasized. Current evidence reveals the importance of incorporating booster vaccination using several vaccine platforms, such as viral vector- and mRNA-based vaccines, as well as other platforms that are under explorative investigations. Further research is being conducted to assess the effectiveness and durability of protection provided by booster COVID-19 vaccination against Omicron and other SARS-CoV-2 variants.

Swine coronaviruses (SCoVs) and their emerging threats to swine population, inter-species transmission, exploring the susceptibility of pigs for SARS-CoV-2 and zoonotic concerns.

Swine coronaviruses (SCoVs) are one of the most devastating pathogens affecting the livelihoods of farmers and swine industry across the world. These include transmissible gastroenteritis virus (TGEV), porcine epidemic diarrhea virus (PEDV), porcine respiratory coronavirus (PRCV), porcine hemagglutinating encephalomyelitis virus (PHEV), swine acute diarrhea syndrome coronavirus (SADS-CoV), and porcine delta coronavirus (PDCoV). Coronaviruses infect a wide variety of animal species and humans because these are having single stranded-RNA that accounts for high mutation rates and thus could break the species barrier. The gastrointestinal, cardiovascular, and nervous systems are the primary organ systems affected by SCoVs. Infection is very common in piglets compared to adult swine causing high mortality in the former. Bat is implicated to be the origin of all CoVs affecting animals and humans. Since pig is the only domestic animal in which CoVs cause a wide range of diseases; new coronaviruses with high zoonotic potential could likely emerge in the future as observed in the past. The recently emerged severe acute respiratory syndrome coronavirus virus-2 (SARS-CoV-2), causing COVID-19 pandemic in humans, has been implicated to have animal origin, also reported from few animal species, though its zoonotic concerns are still under investigation. This review discusses SCoVs and their epidemiology, virology, evolution, pathology, wildlife reservoirs, interspecies transmission, spill-over events and highlighting their emerging threats to swine population. The role of pigs amid ongoing SARS-CoV-2 pandemic will also be discussed. A thorough investigation should be conducted to rule out zoonotic potential of SCoVs and to design appropriate strategies for their prevention and control.

A Review of the Scientific Contributions of Nepal on COVID-19.

Purpose of Review: There has been a high influx of publications on the SARS-CoV-2 and COVID-19 worldwide in the recent few months as very little was known about them. Nepal too had a substantial number of publications on the same, and there was a need to track the most relevant and impactful to the scientific community through bibliometric analysis. Recent Findings: A total of 72 publications were analyzed. Bagmati Pradesh (88%) and its district, Kathmandu (77%), was with the most publications. There were no publications from Gandaki and Karnali Province. Most of the publications were in the international medical journals (82%), 53% chose European journals to publish, and 15.27% were related to and published in psychology journals. The majority were original articles (39%) and mostly related to public health (20.83%). 59.7% of the papers had Nepalese as the first author. Most of them were affiliated with Tribhuvan University Teaching Hospital and Patan Academy of Health Sciences. Summary: Our analysis suggests a need to shift the type of studies from observational studies to studies oriented more towards the therapeutic and clinical trials of available medicines and patient care management. Similarly, the bibliometric analysis gives an overall picture of Nepali medical research's publication status around the globe.

The microbiota-related coinfections in COVID-19 patients: a real challenge.

BACKGROUND: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of ongoing global pandemic of coronavirus disease 2019 (COVID-19), has infected millions of people around the world, especially the elderly and immunocompromised individuals. The infection transmission rate is considered more rapid than other deadly pandemics and severe epidemics encountered earlier, such as Ebola, Zika, Influenza, Marburg, SARS, and MERS. The public health situation therefore is really at a challenging crossroads. MAIN BODY: The internal and external and resident microbiota community is crucial in human health and is essential for immune responses. This community tends to be altered due to pathogenic infections which would lead to severity of the disease as it progresses. Few of these resident microflora become negatively active during infectious diseases leading to coinfection, especially the opportunistic pathogens. Once such a condition sets in, it is difficult to diagnose, treat, and manage COVID-19 in a patient. CONCLUSION: This review highlights the various reported possible coinfections that arise in COVID-19 patients vis-à-vis other serious pathological conditions. The local immunity in lungs, nasal passages, oral cavity, and salivary glands are involved with different aspects of COVID-19 transmission and pathology. Also, the role of adaptive immune system is discussed at the site of infection to control the infection along with the proinflammatory cytokine therapy.

Antioxidant effects of seaweeds and their active compounds on animal health and production - a review.

Natural antioxidants applied as feed additives can improve not only animals' health and overall performance but also increase their resistance to environmental stress such as heat stress, bad housing conditions, diseases, etc. Marine organisms, for example seaweeds - red, brown, and green macroalgae contain a plethora of biologically active substances, including phenolic compounds, polysaccharides, pigments, vitamins, micro- and macroelements, and proteins known for their antioxidant activity, which can help in the maintenance of appropriate redox status in animals and show pleiotropic effects for enhancing good health, and productivity. The dysregulated production of free radicals is a marked characteristic of several clinical conditions, and antioxidant machinery plays a pivotal role in scavenging the excessive free radicals, thereby preventing and treating infections in animals. Supplementation of seaweeds to animal diet can boost antioxidant activity, immunity, and the gut environment. Dietary supplementation of seaweeds can also enhance meat quality due to the deposition of marine-derived antioxidant components in muscles. The use of natural antioxidants in the meat industry is a practical approach to minimize or prevent lipid oxidation. However, overconsumption of seaweeds, especially brown macroalgae, should be avoided because of their high iodine content. An important point to consider when including seaweeds in animal feed is their variable composition which depends on the species, habitat, location, harvest time, growing conditions such as nutrient concentration in water, light intensity, temperature, etc. This review highlights the beneficial applications of seaweeds and their extracted compounds, which have antioxidant properties as feed additives and impact animal health and production.

COVID-19 intranasal vaccines: current progress, advantages, prospects, and challenges.

Multiple vaccines have recently been developed, and almost all the countries are presently vaccinating their population to tackle the COVID-19 pandemic. Most of the COVID-19 vaccines in use are administered via intramuscular (IM) injection, eliciting protective humor and cellular immunity. COVID-19 intranasal (IN) vaccines are also being developed that have shown promising ability to induce a significant amount of antibody-mediated immune response and a robust cell-mediated immunity as well as hold the added ability to stimulate protective mucosal immunity along with the additional advantage of the ease of administration as compared to IM injected vaccines. By inducing secretory IgA antibody responses specifically in the nasal compartment, the intranasal SARS-CoV-2 vaccine can prevent virus infection, replication, shedding, and disease development, as well as possibly limits virus transmission. This article highlights the current progress, advantages, prospects, and challenges in developing intranasal COVID-19 vaccines for countering the ongoing pandemic.

Twin combination of Omicron and Delta variants triggering a tsunami wave of ever high surges in COVID-19 cases: A challenging global threat with a special focus on the Indian subcontinent.

The emergence of Omicron (B.1.1.529) variant of SARS-CoV-2 has resulted into a very massive surge in COVID-19 cases worldwide. Due to continuous emergence of multiple variants of SARS-CoV-2, the ongoing pandemic has caused severe morbidity and mortality in last two years. The rate of infectivity of Omicron variant is much higher than Delta variant and in a very quick time Omicron has displaced the Delta variant and now become a dominant variant across the globe. The twin combination of Omicron and Delta variant is triggering a Tsunami wave of ever high surges in COVID-19 cases worldwide. This article highlights the global threats and challenges posed by Omicron, and strategies to counter it with a particular focus on Indian sub-continent.

SARS-CoV-2 vaccine for domestic and captive animals: An effort to counter COVID-19 pandemic at the human-animal interface.

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has already affected millions worldwide. The emergence of multiple SARS-CoV-2 variants may pose a significant threat to our efforts in controlling the pandemic. The impact of SARS-CoV-2 variants on the efficacy of available vaccines, therapeutics, and diagnostics is currently being investigated. SARS-CoV-2 has been implicated to be originated from animals due to cross-species jumping and raises zoonotic concerns due to the potential for reintroduction into the human populations via interspecies transmission between humans and animals. Natural SARS-CoV-2 infections have been reported in domestic animals (dog, cat, and ferret), captive animals (tiger, lion, snow leopard, puma, otter, and gorilla), and wild and farmed minks. Vaccination of domestic animals can prevent the possible introduction of SARS-CoV-2 into the feral population and subsequent transmission to wildlife. Although the need to vaccinate susceptible animal species, such as cats, minks, and great apes, might seem irrational from a public health standpoint, the successful elimination of SARS-CoV-2 will only be possible by controlling the transmission in all susceptible animal species. This is necessary to prevent the re-emergence of SARS-CoV-2 in the future.

Repurposing benzimidazole and benzothiazole derivatives as potential inhibitors of SARS-CoV-2: DFT, QSAR, molecular docking, molecular dynamics simulation, and in-silico pharmacokinetic and toxicity studies.

Density Functional Theory (DFT) and Quantitative Structure-Activity Relationship (QSAR) studies were performed on four benzimidazoles (compounds 1-4) and two benzothiazoles (compounds 5 and 6), previously synthesized by our group. The compounds were also investigated for their binding affinity and interactions with the SARS-CoV-2 Mpro (PDB ID: 6LU7) and the human angiotensin-converting enzyme 2 (ACE2) receptor (PDB ID: 6 M18) using a molecular docking approach. Compounds 1, 2, and 3 were found to bind with equal affinity to both targets. Compound 1 showed the highest predictive docking scores, and was further subjected to molecular dynamics (MD) simulation to explain protein stability, ligand properties, and protein-ligand interactions. All compounds were assessed for their structural, physico-chemical, pharmacokinetic, and toxicological properties. Our results suggest that the investigated compounds are potential new drug leads to target SARS-CoV-2.

Evolutionary and codon usage preference insights into spike glycoprotein of SARS-CoV-2.

Interaction of SARS-CoV-2 spike glycoprotein with the ACE2 cell receptor is very crucial for virus attachment to human cells. Selected mutations in SARS-CoV-2 S-protein are reported to strengthen its binding affinity to mammalian ACE2. The N501T mutation in SARS-CoV-2-CTD furnishes better support to hotspot 353 in comparison with SARS-CoV and shows higher affinity for receptor binding. Recombination analysis exhibited higher recombination events in SARS-CoV-2 strains, irrespective of their geographical origin or hosts. Investigation further supports a common origin among SARS-CoV-2 and its predecessors, SARS-CoV and bat-SARS-like-CoV. The recombination events suggest a constant exchange of genetic material among the co-infecting viruses in possible reservoirs and human hosts before SARS-CoV-2 emerged. Furthermore, a comprehensive analysis of codon usage bias (CUB) in SARS-CoV-2 revealed significant CUB among the S-genes of different beta-coronaviruses governed majorly by natural selection and mutation pressure. Various indices of codon usage of S-genes helped in quantifying its adaptability in other animal hosts. These findings might help in identifying potential experimental animal models for investigating pathogenicity for drugs and vaccine development experiments.

Immunological aspects and gender bias during respiratory viral infections including novel Coronavirus disease-19 (COVID-19): A scoping review.

The human immune system is not adequately equipped to eliminate new microbes and could result in serious damage on first exposure. This is primarily attributed to the exaggerated immune response (inflammatory disease), which may prove detrimental to the host, as evidenced by SARS-CoV-2 infection. From the experiences of Novel Coronavirus Disease-19 to date, male patients are likely to suffer from high-intensity inflammation and disease severity than the female population. Hormones are considered the significant pillars of sex differences responsible for the discrepancy in immune response exhibited by males and females. Females appear to be better equipped to counter invading respiratory viral pathogens, including the novel SARS-CoV-2, than males. It can be hypothesized that females are more shielded from disease severity, probably owing to the diverse action/influence of estrogen and other sex hormones on both cellular (thymus-derived T lymphocytes) and humoral immunity (antibodies).

SARS-CoV-2 infection in domestic and feral cats: current evidence and implications.

Current evidence indicates that cats play a limited role in COVID-19 epidemiology, and pets are probably dead-end hosts of SARS-CoV-2 and pose negligible risks of transmission to humans. Still, one health concept is to be adopted widely as a component of mitigation strategies to tackle the ongoing pandemic. Therefore, in terms of the magnitude of infection and potential to transmit SARS-CoV-2 to humans, our surveillance efforts should mainly focus on mustelids (especially minks, ferrets, and others) for early detection and control of infection. This will ensure that SARS-CoV-2 will not get established in the wild animal population of these susceptible species. We agree with Dr. Passarella Teixeira on the possibility of domestic and feral cats acting as an urban reservoir, subsequently transmitting the virus to human beings. However, it is less likely that such a phenomenon will be reported even if it has occurred due to the efficient and extensive human-to-human transmission of SARS-CoV-2.

COVID-19 vaccination passport: prospects, scientific feasibility, and ethical concerns.

A vaccination passport (also known as "vaccination certificate," "immunization passport," or "digital health pass") is a document that provides proof of vaccination and certifies that the holder is protected from illness. It is a more reliable and practical substitute for immunity passports since COVID-19 vaccination is considered a better correlate of protection. Vaccination passport can be considered as a tool offering the holder the privilege of traveling freely within countries without any restrictions. The majority of the countries that are dependent on travel and tourism have exhibited a positive inclination toward implementing COVID-19 vaccination passports, while others have a mixed opinion. The successful implementation of vaccination passports will be a complex task for the policymakers as it requires addressing several ethical, legal, and data security concerns outlined in this article. However, vaccination passports can offer economic and health benefits that will allow the gradual recovery of the economy.

COVID-19 vaccine hesitancy - reasons and solutions to achieve a successful global vaccination campaign to tackle the ongoing pandemic.

The ongoing coronavirus disease (COVID-19) vaccination drive aims to achieve global vaccination coverage that will help to control the pandemic. Therefore, the individuals who are reluctant to be vaccinated or forego COVID-19 vaccination can delay the progress of overall vaccination coverage, leading to slower vaccination rates and may create obstacles in global efforts to control the circulation of SARS-CoV-2 as unvaccinated individuals can act as reservoirs of SARS-CoV-2 and could drive further outbreaks. Vaccine hesitancy is one of the major threats that directly impact global health as it challenges our ability to eradicate infectious diseases and achieve significant herd immunity through vaccination. One of the strategies to counter vaccine hesitancy is to follow a multisectoral approach that involves the collaboration between various stakeholders, such as government, private companies, religious groups, and other agencies, to leverage the knowledge, expertise, and resources, thereby enabling the creation of longstanding public trust of vaccines.

Emerging SARS-CoV-2 variants: impact on vaccine efficacy and neutralizing antibodies.

The genetic variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been emerging and circulating in different parts of the world from the beginning of the coronavirus disease (COVID-19) pandemic. Variants are divided into three classes: variant of interest, variant of concern, and variant of high consequence depending on its impact on the transmission, disease severity, diagnostics, vaccines, and therapeutics. The variants of concern include the United Kingdom variant (B.1.1.7), South Africa variant (B.1.351), two related California variants (B.1.427 and B.1.429), and Brazil variant (P.1). These SARS-CoV-2 variants have a direct impact on the available COVID-19 vaccines and immunotherapeutics as they can alter the neutralizing activity of vaccine-elicited antibodies and monoclonal antibodies resulting in mild-to-substantial loss of efficacy. There is a need to establish surveillance systems that can monitor the emergence of novel SARS-CoV-2 variants worldwide.

Viral Dynamics and Real-Time RT-PCR Ct Values Correlation with Disease Severity in COVID-19.

Real-time RT-PCR is considered the gold standard confirmatory test for coronavirus disease 2019 (COVID-19). However, many scientists disagree, and it is essential to understand that several factors and variables can cause a false-negative test. In this context, cycle threshold (Ct) values are being utilized to diagnose or predict SARS-CoV-2 infection. This practice has a significant clinical utility as Ct values can be correlated with the viral load. In addition, Ct values have a strong correlation with multiple haematological and biochemical markers. However, it is essential to consider that Ct values might be affected by pre-analytic, analytic, and post-analytical variables such as collection technique, specimen type, sampling time, viral kinetics, transport and storage conditions, nucleic acid extraction, viral RNA load, primer designing, real-time PCR efficiency, and Ct value determination method. Therefore, understanding the interpretation of Ct values and other influential factors could play a crucial role in interpreting viral load and disease severity. In several clinical studies consisting of small or large sample sizes, several discrepancies exist regarding a significant positive correlation between the Ct value and disease severity in COVID-19. In this context, a revised review of the literature has been conducted to fill the knowledge gaps regarding the correlations between Ct values and severity/fatality rates of patients with COVID-19. Various databases such as PubMed, Science Direct, Medline, Scopus, and Google Scholar were searched up to April 2021 by using keywords including "RT-PCR or viral load", "SARS-CoV-2 and RT-PCR", "Ct value and viral load", "Ct value or COVID-19". Research articles were extracted and selected independently by the authors and included in the present review based on their relevance to the study. The current narrative review explores the correlation of Ct values with mortality, disease progression, severity, and infectivity. We also discuss the factors that can affect these values, such as collection technique, type of swab, sampling method, etc.