Genomic Cues From Beta-Coronaviruses and Mammalian Hosts Sheds Light on Probable Origins and Infectivity of SARS-CoV-2 Causing COVID-19

4’-fluorouridine as a potential COVID-19 oral drug?: a review

The available antiviral drugs against coronavirus disease 2019 (COVID-19) are limited. Oral drugs that can be prescribed to non-hospitalized patients are required. The 4′-fluoruridine, a nucleoside analog similar to remdesivir, is one of the promising candidates for COVID-19 oral therapy due to its ability to stall viral RdRp. Available data suggested that 4'-fluorouridine has antiviral activity against the respiratory syncytial virus, hepatitis C virus, lymphocytic choriomeningitis virus, and other RNA viruses, including SARS-CoV-2. In vivo study revealed that SARS-CoV-2 is highly susceptible to 4'-fluorouridine and was effective with a single daily dose versus molnupiravir administered twice daily. Although  4'-fluorouridine is considered as strong candidates, further studies are required to determine its efficacy in the patients and  it’s genetic effects on humans. In this review, we the antiviral activity of 4′-fluorouridine is reviewed and compared it to other drugs currently in development. The current literature on 4′-fluorouridine's antiviral activity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is compiled and discussed.

4’-fluorouridine and its derivatives as potential COVID-19 oral drugs: a review

Background: Although vaccination is underway, antiviral drugs against coronavirus disease 2019 (COVID-19) are lacking. Remdesivir, a nucleoside analog that works by inhibiting the viral RNA-dependent RNA polymerase (RdRp), is the only fully approved antiviral for the treatment of COVID-19. However, it is limited to intravenous use and is usually recommended only for hospitalized patients with severe COVID-19; therefore, oral drugs that can be prescribed even to non-hospitalized patients are required. According to a recent study, 4′-fluoruridine, a nucleoside analog similar to remdesivir, is a promising candidate for COVID-19 oral therapy due to its ability to stall viral RdRp. Methods: We examined the antiviral activity of 4′-fluorouridine and compared it to other drugs currently in development. The current literature on 4′-fluorouridine's antiviral activity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been compiled and discussed in this review. Results: The 4'-fluorouridine has antiviral activity against the respiratory syncytial virus, hepatitis C virus, lymphocytic choriomeningitis virus, and other RNA viruses, including SARS-CoV-2. In vitro studies have shown that SARS-CoV-2 is susceptible to 4'-fluorouridine, with the half-maximal effective concentration (EC50) of 0.2 to 0.6 M, and that the 4′-fluorouridine derivative, 4′-fluorouridine-5′-triphosphate, inhibited RdRp via a mechanism distinct from that of the already approved COVID-19 oral drug, molnupiravir. In addition, an in vivo study revealed that SARS-CoV-2 is highly susceptible to 4'-fluorouridine and was effective with a single daily dose versus molnupiravir administered twice daily. Conclusions: Concerns about the genetic effects of molnupiravir may be resolved by the use of 4′-fluorouridine and its derivative, which, unlike molnupiravir, do not alter genetics, but inhibit RdRp instead. Although they are currently considered as strong candidates, further studies are required to determine the antiviral activity of 4′-fluorouridine and its derivative against SARS-CoV-2 and their genetic effects on humans.

COVID-19 in Solid Organ Transplant Recipients: a Review of the Current Literature

Purpose of review

The approach to ongoing organ transplantation and management of COVID-19 in solid organ transplant recipients (SOTR) has evolved tremendously since the pandemic’s beginning. We summarize the current literature surrounding the virology of SARS-CoV-2, epidemiology of COVID-19 in transplant recipients, review the clinical features and complications of COVID-19 in SOTR, and discuss the safety and efficacy of current therapies and candidate vaccines in this population.

Recent findings

Despite initial suspensions in organ transplantation during early 2020, routine donor testing and de-crowding of hospitals have allowed transplant activity to resume at pre-pandemic rates. COVID-19-associated mortality in SOTR is similar to that of the general population, and lower than that of patients with end-organ disease awaiting transplant. The optimal approach to immunosuppression in SOTR with COVID-19 is unknown and disease severity may influence management decisions. Many vaccines in development are likely to be safe for immunocompromised hosts, though post-marketing investigations will be required to determine the efficacy in the SOTR.

Summary

Though there are multiple unique considerations in the care of SOTR with COVID-19, immunosuppression does not appear to have a detrimental impact on overall outcome. Organ transplantation remains a lifesaving intervention and can be safely performed despite a global pandemic.

Exploring SARS-COV-2 structural proteins to design a multi-epitope vaccine using immunoinformatics approach: An in silico study

In December 2019, a new virus called SARS-CoV-2 was reported in China and quickly spread to other parts of the world. The development of SARS-COV-2 vaccines has recently received much attention from numerous researchers. The present study aims to design an effective multi-epitope vaccine against SARS-COV-2 using the reverse vaccinology method. In this regard, structural proteins from SARS-COV-2, including the spike (S), envelope (E), membrane (M), and nucleocapsid (N) proteins, were selected as target antigens for epitope prediction. A total of five helper T lymphocytes (HTL) and five cytotoxic T lymphocytes (CTL) epitopes were selected after screening the predicted epitopes for antigenicity, allergenicity, and toxicity. Subsequently, the selected HTL and CTL epitopes were fused via flexible linkers. Next, the cholera toxin B-subunit (CTxB) as an adjuvant was linked to the N-terminal of the chimeric structure. The proposed vaccine was analyzed for the properties of physicochemical, antigenicity, and allergenicity. The 3D model of the vaccine construct was predicted and docked with the Toll-like receptor 4 (TLR4). The molecular dynamics (MD) simulation was performed to evaluate the stable interactions between the vaccine construct and TLR4. The immune simulation was also conducted to explore the immune responses induced by the vaccine. Finally, in silico cloning of the vaccine construct into the pET-28 (+) vector was conducted. The results obtained from all bioinformatics analysis stages were satisfactory; however, in vitro and in vivo tests are essential to validate these results.