An antibody cocktail with broadened mutational resistance and effective protection against SARS-CoV-2.

Neutralizing antibodies have been proven to be highly effective in treating mild and moderate COVID-19 patients, but continuous emergence of SARS-CoV-2 variants poses significant challenges. Antibody cocktail treatments reduce the risk of escape mutants and resistance. In this study, a new cocktail composed of two highly potent neutralizing antibodies (HB27 and H89Y) was developed, whose binding epitope is different from those cocktails that received emergency use authorization. This cocktail showed more potent and balanced neutralizing activities (IC50 0.9-11.3 ng mL-1) against a broad spectrum of SARS-CoV-2 variants over individual HB27 or H89Y antibodies. Furthermore, the cocktail conferred more effective protection against the SARS-CoV-2 Beta variant in an aged murine model than monotherapy. It was shown to prevent SARS-CoV-2 mutational escape in vitro and effectively neutralize 61 types of pseudoviruses harbouring single amino acid mutation originated from variants and escape strains of Bamlanivimab, Casirivimab and Imdevimab with IC50 of 0.6-65 ng mL-1. Despite its breadth of variant neutralization, the HB27+H89Y combo and EUA cocktails lost their potencies against Omicron variant. Our results provide important insights that new antibody cocktails covering different epitopes are valuable tools to counter virus mutation and escape, highlighting the need to search for more conserved epitopes to combat Omicron.

Rational Development of Hypervalent Glycan Shield-Binding Nanoparticles with Broad-Spectrum Inhibition against Fatal Viruses Including SARS-CoV-2 Variants.

Infectious virus diseases, particularly coronavirus disease 2019, have posed a severe threat to public health, whereas the developed therapeutic and prophylactic strategies are seriously challenged by viral evolution and mutation. Therefore, broad-spectrum inhibitors of viruses are highly demanded. Herein, an unprecedented antiviral strategy is reported, targeting the viral glycan shields with hypervalent mannose-binding nanoparticles. The nanoparticles exhibit a unique double-punch mechanism, being capable of not only blocking the virus-receptor interaction but also inducing viral aggregation, thereby allowing for inhibiting the virus entry and facilitating the phagocytosis of viruses. The nanoparticles exhibit potent and broad-spectrum antiviral efficacy to multiple pseudoviruses, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its major variants (D614G, N501Y, N439K, Δ69-70, Delta, and Omicron; lentiviruses expressing only the spike proteins), as well as other vital viruses (human immunodeficiency virus 1 and Lassa virus), with apparent EC50 values around the 10-9  m level. Significantly, the broad-spectrum inhibition of authentic viruses of both wild-type SARS-CoV-2 and Delta variants is confirmed. Therefore, this hypervalent glycan-shield targeting strategy opens new access to broad-spectrum viral inhibition.

An Engineered IgG-VHH Bispecific Antibody against SARS-CoV-2 and Its Variants.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) neutralizing antibodies are shown to be effective therapeutics for providing coronavirus disease 2019 (COVID-19) protection. However, recurrent variants arise and facilitate significant escape from current antibody therapeutics. Bispecific antibodies (bsAbs) represent a unique platform to increase antibody breadth and to reduce neutralization escape. Herein, a novel immunoglobulin G-variable domains of heavy-chain-only antibody (IgG-VHH) format bsAb derived from a potent human antibody R15-F7 and a humanized nanobody P14-F8-35 are rationally engineered. The resulting bsAb SYZJ001 efficiently neutralizes wild-type SARS-CoV-2 as well as the alpha, beta, gamma, and delta variants, with superior efficacy to its parental antibodies. Cryo-electron microscopy structural analysis reveals that R15-F7 and P14-F8-35 bind to nonoverlapping epitopes within the RBD and sterically hindered ACE2 receptor binding. Most importantly, SYZJ001 shows potent prophylactic and therapeutic efficacy against SARS-CoV-2 in three established mouse models. Collectively, the current results demonstrate that the novel bsAb format is feasible and effective, suggesting great potential as an inspiring antiviral strategy.

Discovery and characterization of SARS-CoV-2 reactive and neutralizing antibodies from humanized CAMouseHG mice through rapid hybridoma screening and high-throughput single-cell V(D)J sequencing.

The coronavirus disease 2019 pandemic has caused more than 532 million infections and 6.3 million deaths to date. The reactive and neutralizing fully human antibodies of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are effective detection tools and therapeutic measures. During SARS-CoV-2 infection, a large number of SARS-CoV-2 reactive and neutralizing antibodies will be produced. Most SARS-CoV-2 reactive and neutralizing fully human antibodies are isolated from human and frequently encoded by convergent heavy-chain variable genes. However, SARS-CoV-2 viruses can mutate rapidly during replication and the resistant variants of neutralizing antibodies easily survive and evade the immune response, especially in the face of such focused antibody responses in humans. Therefore, additional tools are needed to develop different kinds of fully human antibodies to compensate for current deficiency. In this study, we utilized antibody humanized CAMouseHG mice to develop a rapid antibody discovery method and examine the antibody repertoire of SARS-CoV-2 RBD-reactive hybridoma cells derived from CAMouseHG mice by using high-throughput single-cell V(D)J sequencing analysis. CAMouseHG mice were immunized by 28-day rapid immunization method. After electrofusion and semi-solid medium screening on day 12 post-electrofusion, 171 hybridoma clones were generated based on the results of SARS-CoV-2 RBD binding activity assay. A rather obvious preferential usage of IGHV6-1 family was found in these hybridoma clones derived from CAMouseHG mice, which was significantly different from the antibodies found in patients with COVID-19. After further virus neutralization screening and antibody competition assays, we generated a noncompeting two-antibody cocktail, which showed a potent prophylactic protective efficacy against SARS-CoV-2 in cynomolgus macaques. These results indicate that humanized CAMouseHG mice not only provide a valuable platform to obtain fully human reactive and neutralizing antibodies but also have a different antibody repertoire from humans. Thus, humanized CAMouseHG mice can be used as a good complementary tool in discovery of fully human therapeutic and diagnostic antibodies.

Characterization of the Immune Response of MERS-CoV Vaccine Candidates Derived from Two Different Vectors in Mice.

Middle East respiratory syndrome (MERS) is an acute, high-mortality-rate, severe infectious disease caused by an emerging MERS coronavirus (MERS-CoV) that causes severe respiratory diseases. The continuous spread and great pandemic potential of MERS-CoV make it necessarily important to develop effective vaccines. We previously demonstrated that the application of Gram-positive enhancer matrix (GEM) particles as a bacterial vector displaying the MERS-CoV receptor-binding domain (RBD) is a very promising MERS vaccine candidate that is capable of producing potential neutralization antibodies. We have also used the rabies virus (RV) as a viral vector to design a recombinant vaccine by expressing the MERS-CoV S1 (spike) protein on the surface of the RV. In this study, we compared the immunological efficacy of the vaccine candidates in BALB/c mice in terms of the levels of humoral and cellular immune responses. The results show that the rabies virus vector-based vaccine can induce remarkably earlier antibody response and higher levels of cellular immunity than the GEM particles vector. However, the GEM particles vector-based vaccine candidate can induce remarkably higher antibody response, even at a very low dose of 1 µg. These results indicate that vaccines constructed using different vaccine vector platforms for the same pathogen have different rates and trends in humoral and cellular immune responses in the same animal model. This discovery not only provides more alternative vaccine development platforms for MERS-CoV vaccine development, but also provides a theoretical basis for our future selection of vaccine vector platforms for other specific pathogens.

Rational development of a combined mRNA vaccine against COVID-19 and influenza.

As the world continues to experience the COVID-19 pandemic, seasonal influenza remain a cause of severe morbidity and mortality globally. Worse yet, coinfection with SARS-CoV-2 and influenza A virus (IAV) leads to more severe clinical outcomes. The development of a combined vaccine against both COVID-19 and influenza is thus of high priority. Based on our established lipid nanoparticle (LNP)-encapsulated mRNA vaccine platform, we developed and characterized a novel mRNA vaccine encoding the HA antigen of influenza A (H1N1) virus, termed ARIAV. Then, ARIAV was combined with our COVID-19 mRNA vaccine ARCoV, which encodes the receptor-binding domain (RBD) of the SARS-CoV-2 S protein, to formulate the final combined vaccine, AR-CoV/IAV. Further characterization demonstrated that immunization with two doses of AR-CoV/IAV elicited robust protective antibodies as well as antigen-specific cellular immune responses against SARS-CoV-2 and IAV. More importantly, AR-CoV/IAV immunization protected mice from coinfection with IAV and the SARS-CoV-2 Alpha and Delta variants. Our results highlight the potential of the LNP-mRNA vaccine platform in preventing COVID-19 and influenza, as well as other respiratory diseases.

Rational Development of a Polysaccharide–Protein-Conjugated Nanoparticle Vaccine Against SARS-CoV-2 Variants and Streptococcus pneumoniae (Adv. Mater. 21/2022)

Nanoparticle Vaccines In article number 2200443, Liangzhi Xie, Chengfeng Qin, and co-workers develop a novel bivalent nanoparticle vaccine that confers protection against infection of multiple SARS-CoV-2 variants and Streptococcus pneumoniae. This universal polysaccharide?protein-conjugated vaccine platform provides a powerful tool to fight against cocirculating viral and bacterial pathogens worldwide.

Rational development of a combined mRNA vaccine against COVID-19 and influenza (preprint)

As the world continues to experience the COVID-19 pandemic, seasonal influenza remain a cause of severe morbidity and mortality globally. Worse yet, coinfection with SARS-CoV-2 and influenza A virus (IAV) leads to more severe clinical outcomes. The development of a combined vaccine against both COVID-19 and influenza is thus of high priority. Based on our established lipid nanoparticle (LNP)-encapsulated mRNA vaccine platform, we developed and characterized a novel mRNA vaccine encoding the HA antigen of influenza A (H1N1) virus, termed ARIAV. Then, ARIAV was combined with our COVID-19 mRNA vaccine ARCoV, which encodes the receptor binding domain (RBD) of the SARS-CoV-2 S protein, to formulate the final combined vaccine, AR-CoV/IAV. Further characterization demonstrated that immunization with two doses of AR-CoV/IAV elicited robust protective antibodies as well as antigen-specific cellular immune responses against SARS-CoV-2 and IAV. More importantly, AR-CoV/IAV immunization protected mice from coinfection with IAV and the SARS-CoV-2 Alpha and Delta variants. Our results highlight the potential of the LNP-mRNA vaccine platform in preventing COVID-19 and influenza, as well as other respiratory diseases.

Human liver organoid derived intra-hepatic bile duct cells support SARS-CoV-2 infection and replication.

Although the main route of infection for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the respiratory tract, liver injury is also commonly seen in many patients, as evidenced by deranged parenchymal liver enzymes. Furthermore, the severity of liver damage has been shown to correlate with higher mortality. Overall, the mechanism behind the liver injury remains unclear. We showed in this study that intra-hepatic bile duct cells could be grown using a human liver organoid platform. The cholangiocytes were not only susceptible to SARS-CoV-2 infection, they also supported efficient viral replication. We also showed that SARS-CoV-2 replication was much higher than SARS-CoV. Our findings suggested direct cytopathic viral damage being a mechanism for SARS-CoV-2 liver injury.

Rational Development of a Polysaccharide-Protein-Conjugated Nanoparticle Vaccine Against SARS-CoV-2 Variants and Streptococcus pneumoniae.

The ongoing COVID-19 pandemic caused by SARS-CoV-2 has led to millions of deaths worldwide. Streptococcus pneumoniae (S. pneumoniae) remains a major cause of mortality in underdeveloped countries. A vaccine that prevents both SARS-CoV-2 and S. pneumoniae infection represents a long-sought "magic bullet". Herein, a nanoparticle vaccine, termed SCTV01B, is rationally developed by using the capsular polysaccharide of S. pneumoniae serotype 14 (PPS14) as the backbone to conjugate with the recombinant receptor-binding domain (RBD) of the SARS-CoV-2 spike protein. The final formulation of conjugated nanoparticles in the network structure exhibits high thermal stability. Immunization with SCTV01B induces potent humoral and Type 1/Type 2 T helper cell (Th1/Th2) cellular immune responses in mice, rats, and rhesus macaques. In particular, SCTV01B-immunized serum not only broadly cross-neutralizes all SARS-CoV-2 variants of concern (VOCs), including the most recent Omicron variant, but also shows high opsonophagocytic activity (OPA) against S. pneumoniae serotype 14. Finally, SCTV01B vaccination confers protection against challenges with the SARS-CoV-2 mouse-adapted strain and the original strain in established murine models. Collectively, these promising preclinical results support further clinical evaluation of SCTV01B, highlighting the potency of polysaccharide-RBD-conjugated nanoparticle vaccine platforms for the development of vaccines for COVID-19 and other infectious diseases.

Comparative characterization of SARS-CoV-2 variants of concern and mouse-adapted strains in mice.

SARS-CoV-2 has evolved into a panel of variants of concern (VOCs) and constituted a sustained threat to global health. The wildtype (WT) SARS-CoV-2 isolates fail to infect mice, while the Beta variant, one of the VOCs, has acquired the capability to infect standard laboratory mice, raising a spreading risk of SARS-CoV-2 from humans to mice. However, the infectivity and pathogenicity of other VOCs in mice remain not fully understood. In this study, we systematically investigated the infectivity and pathogenicity of three VOCs, Alpha, Beta, and Delta, in mice in comparison with two well-understood SARS-CoV-2 mouse-adapted strains, MASCp6 and MASCp36, sharing key mutations in the receptor-binding domain (RBD) with Alpha or Beta, respectively. Our results showed that the Beta variant had the strongest infectivity and pathogenicity among the three VOCs, while the Delta variant only caused limited replication and mild pathogenic changes in the mouse lung, which is much weaker than what the Alpha variant did. Meanwhile, Alpha showed comparable infectivity in lungs in comparison with MASCp6, and Beta only showed slightly lower infectivity in lungs when compared with MASCp36. These results indicated that all three VOCs have acquired the capability to infect mice, highlighting the ongoing spillover risk of SARS-CoV-2 from humans to mice during the continued evolution of SARS-CoV-2, and that the key amino acid mutations in the RBD of mouse-adapted strains may be referenced as an early-warning indicator for predicting the spillover risk of newly emerging SARS-CoV-2 variants.

Lipid nanoparticle-encapsulated mRNA antibody provides long-term protection against SARS-CoV-2 in mice and hamsters.

Monoclonal antibodies represent important weapons in our arsenal to against the COVID-19 pandemic. However, this potential is severely limited by the time-consuming process of developing effective antibodies and the relative high cost of manufacturing. Herein, we present a rapid and cost-effective lipid nanoparticle (LNP) encapsulated-mRNA platform for in vivo delivery of SARS-CoV-2 neutralization antibodies. Two mRNAs encoding the light and heavy chains of a potent SARS-CoV-2 neutralizing antibody HB27, which is currently being evaluated in clinical trials, were encapsulated into clinical grade LNP formulations (named as mRNA-HB27-LNP). In vivo characterization demonstrated that intravenous administration of mRNA-HB27-LNP in mice resulted in a longer circulating half-life compared with the original HB27 antibody in protein format. More importantly, a single prophylactic administration of mRNA-HB27-LNP provided protection against SARS-CoV-2 challenge in mice at 1, 7 and even 63 days post administration. In a close contact transmission model, prophylactic administration of mRNA-HB27-LNP prevented SARS-CoV-2 infection between hamsters in a dose-dependent manner. Overall, our results demonstrate a superior long-term protection against SARS-CoV-2 conferred by a single administration of this unique mRNA antibody, highlighting the potential of this universal platform for antibody-based disease prevention and therapy against COVID-19 as well as a variety of other infectious diseases.

Memory B cell repertoire from triple vaccinees against diverse SARS-CoV-2 variants.

Omicron (B.1.1.529), the most heavily mutated SARS-CoV-2 variant so far, is highly resistant to neutralizing antibodies, raising concerns about the effectiveness of antibody therapies and vaccines1,2. Here we examined whether sera from individuals who received two or three doses of inactivated SARS-CoV-2 vaccine could neutralize authentic Omicron. The seroconversion rates of neutralizing antibodies were 3.3% (2 out of 60) and 95% (57 out of 60) for individuals who had received 2 and 3 doses of vaccine, respectively. For recipients of three vaccine doses, the geometric mean neutralization antibody titre for Omicron was 16.5-fold lower than for the ancestral virus (254). We isolated 323 human monoclonal antibodies derived from memory B cells in triple vaccinees, half of which recognized the receptor-binding domain, and showed that a subset (24 out of 163) potently neutralized all SARS-CoV-2 variants of concern, including Omicron. Therapeutic treatments with representative broadly neutralizing monoclonal antibodies were highly protective against infection of mice with SARS-CoV-2 Beta (B.1.351) and Omicron. Atomic structures of the Omicron spike protein in complex with three classes of antibodies that were active against all five variants of concern defined the binding and neutralizing determinants and revealed a key antibody escape site, G446S, that confers greater resistance to a class of antibodies that bind on the right shoulder of the receptor-binding domain by altering local conformation at the binding interface. Our results rationalize the use of three-dose immunization regimens and suggest that the fundamental epitopes revealed by these broadly ultrapotent antibodies are rational targets for a universal sarbecovirus vaccine.

Post-ST-Segment Elevation Myocardial Infarction Follow-Up Care During the COVID-19 Pandemic and the Possible Benefit of Telemedicine: An Observational Study.

Background: Infectious control measures during the COVID-19 pandemic have led to the propensity toward telemedicine. This study examined the impact of telemedicine during the pandemic on the long-term outcomes of ST-segment elevation myocardial infarction (STEMI) patients. Methods: This study included 288 patients admitted 1 year before the pandemic (October 2018-December 2018) and during the pandemic (January 2020-March 2020) eras, and survived their index STEMI admission. The follow-up period was 1 year. One-year primary safety endpoint was all-cause mortality. Secondary safety endpoints were cardiac readmissions for unplanned revascularisation, non-fatal myocardial infarction, heart failure, arrythmia, unstable angina. Major adverse cardiovascular events (MACE) was defined as the composite outcome of each individual safety endpoint. Results: Despite unfavorable in-hospital outcomes among patients admitted during the pandemic compared to pre-pandemic era, both groups had similar 1-year all-cause mortality (11.2 vs. 8.5%, respectively, p = 0.454) but higher cardiac-related (14.1 vs. 5.1%, p < 0.001) and heart failure readmissions in the pandemic vs. pre-pandemic groups (7.1 vs. 1.7%, p = 0.037). Follow-up was more frequently conducted via teleconsultations (1.2 vs. 0.2 per patient/year, p = 0.001), with reduction in physical consultations (2.1 vs. 2.6 per patient/year, p = 0.043), during the pandemic vs. pre-pandemic era. Majority achieved guideline-directed medical therapy (GDMT) during pandemic vs. pre-pandemic era (75.9 vs. 61.6%, p = 0.010). Multivariable Cox regression demonstrated achieving medication target doses (HR 0.387, 95% CI 0.164-0.915, p = 0.031) and GDMT (HR 0.271, 95% CI 0.134-0.548, p < 0.001) were independent predictors of lower 1-year MACE after adjustment. Conclusion: The pandemic has led to the wider application of teleconsultation, with increased adherence to GDMT, enhanced medication target dosing. Achieving GDMT was associated with favorable long-term prognosis.

The Global Effect of the COVID-19 Pandemic on STEMI Care: A Systematic Review and Meta-analysis.

BACKGROUND: The COVID-19 pandemic has affected patients with ST-segment elevation myocardial infarction (STEMI) requiring primary percutaneous coronary intervention (PCI) worldwide. In this review we examine the global effect of the COVID-19 pandemic on incidence of STEMI admissions, and relationship between the pandemic and door to balloon time (D2B), all-cause mortality, and other secondary STEMI outcomes. METHODS: We performed a systematic review and meta-analysis to primarily compare D2B time and in-hospital mortality of STEMI patients who underwent primary PCI during and before the pandemic. Subgroup analyses were performed to investigate the influence of geographical region and income status of a country on STEMI care. An online database search included studies that compared the aforementioned outcomes of STEMI patients during and before the pandemic. RESULTS: In total, 32 articles were analyzed. Overall, 19,140 and 68,662 STEMI patients underwent primary PCI during and before the pandemic, respectively. Significant delay in D2B was observed during the pandemic (weighted mean difference, 8.10 minutes; 95% confidence interval [CI], 3.90-12.30 minutes; P = 0.0002; I2 = 90%). In-hospital mortality was higher during the pandemic (odds ratio [OR], 1.27; 95% CI, 1.09-1.49; P = 0.002; I2 = 36%), however this varied with factors such as geographical location and income status of a country. Subgroup analysis showed that low-middle-income countries observed a higher rate of mortality during the pandemic (OR, 1.52; 95% CI, 1.13-2.05; P = 0.006), with a similar but insignificant trend seen among the high income countries (OR, 1.17; 95% CI, 0.95-1.44; P = 0.13). CONCLUSIONS: The COVID-19 pandemic is associated with worse STEMI performance metrics and clinical outcome, particularly in the Eastern low-middle-income status countries. Better strategies are needed to address these global trends in STEMI care during the pandemic.

One-year outcomes of patients with ST-segment elevation myocardial infarction during the COVID-19 pandemic.

The pandemic has led to adverse short-term outcomes for patients with ST-segment elevation myocardial infarction (STEMI). It is unknown if this translates to poorer long-term outcomes. In Singapore, the escalation of the outbreak response on February 7, 2020 demanded adaptation of STEMI care to stringent infection control measures. A total of 321 patients presenting with STEMI and undergoing primary percutaneous coronary intervention at a tertiary hospital were enrolled and followed up over 1-year. They were allocated into three groups based on admission date-(1) Before outbreak response (BOR): December 1, 2019-February 6, 2020, (2) During outbreak response (DOR): February 7-March 31, 2020, and (3) control group: November 1-December 31, 2018. The incidence of cardiac-related mortality, cardiac-related readmissions, and recurrent coronary events were examined. Although in-hospital outcomes were worse in BOR and DOR groups compared to the control group, there were no differences in the 1-year cardiac-related mortality (BOR 8.7%, DOR 7.1%, control 4.8%, p = 0.563), cardiac-related readmissions (BOR 15.1%, DOR 11.6%, control 12.0%, p = 0.693), and recurrent coronary events (BOR 3.2%, DOR 1.8%, control 1.2%, p = 0.596). There were higher rates of additional PCI during the index admission in DOR, compared to BOR and control groups (p = 0.027). While patients admitted for STEMI during the pandemic may have poorer in-hospital outcomes, their long-term outcomes remain comparable to the pre-pandemic era.

How to manage patients with suspected upper tract urothelial carcinoma in the pandemic of COVID-19?

BACKGROUND: The pandemic of COVID-19 has disrupted the clinical pathway for patients with suspected upper tract urothelial carcinoma (UTUC). This aims to investigate the optimal management of UTUC during the pandemic by determining 1) Whether a three-month delay of RNU leads to worsened overall survival, 2) Whether radical nephroureterectomy (RNU) can be performed without prior diagnostic ureteroscopy (URS). METHODS: Consecutive patients with RNU performed for suspected UTUC in four hospitals in Hong Kong and Taiwan were included. Patients with histologically proven UTUC and with RNU performed within one year were dichotomized into early (≤3 months) and delayed (>3 months) RNU groups. Diagnostic performances of predictive models based on pre-URS factors (gross haematuria, suspicious or malignant urine cytology, and filling defect or contrast-enhancing mass on computed tomography), with or without URS, were analysed using receiver operating characteristics and area under curve (AUC). Overall survival was analysed using Kaplan-Meier method and multivariate Cox regression analysis. RESULTS: Between 2000 and 2019, 665 patients underwent RNU, and 491 of them had prior diagnostic URS. The early RNU group had a better overall survival (P = 0.015). Early RNU was associated with a better overall survival upon multivariate analysis (HR 1.55, 95% CI 1.03-2.33, P = 0.035). Large tumour size, multi-focal tumour, T2 or above disease, and positive nodal status were associated with a poorer overall survival. A combination of any 2 out of the 3 pre-URS factors achieved a positive predictive value of 99.5 to 100%. Presence of all 3 pre-URS factors achieved an AUC of 0.851 with URS, and AUC of 0.809 without URS. CONCLUSIONS: A delay of RNU for over 3 months was associated with poorer overall survival and has to be avoided despite the current COVID-19. We can also consider direct RNU based on clinical factors alone. This also avoids URS hospitalization and expedites the clinical pathway of UTUC.

Inhaled Dry Powder Formulation of Tamibarotene, a Broad-Spectrum Antiviral against Respiratory Viruses Including SARS-CoV-2 and Influenza Virus

Abstract In response to the epidemic and pandemic threats caused by emerging respiratory viral infections, a safe and efficient broad-spectrum antiviral therapy at early onset of infection can significantly improve patients? outcome. Inhaled dry powder is easy to administer and delivers antiviral agent directly to the primary site of infection, thereby minimizing systemic side effects. Here, spray freeze drying (SFD) technique is employed to formulate tamibarotene, a retinoid derivative with broad-spectrum antiviral activity, as inhalable powder. The SFD tamibarotene powder exhibits desirable physicochemical and aerodynamic properties for inhalation. Pulmonary delivery of tamibarotene powder results in rapid absorption and higher bioavailability compared with intraperitoneal injection of unformulated drug in animals. More importantly, inhalation or intranasal delivery of SFD tamibarotene formulation displays broad-spectrum antiviral activity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), Middle East respiratory syndrome coronavirus, and pandemic 2009 influenza A virus (H1N1) in mouse and hamster models by targeting lower or upper airways, and the efficacy is comparable or superior to the commercially available antivirals remdesivir and zanamivir against specific virus. These results present a promising strategy to combat various respiratory viral infections including SARS-CoV-2 and influenza virus, or even co-infection.

Nucleic acid visualization assay for Middle East Respiratory Syndrome Coronavirus (MERS-CoV) by targeting the UpE and N gene.

Since its first emergence in 2012, cases of infection with Middle East respiratory syndrome coronavirus (MERS-CoV) have continued to occur. At the end of January 2020, 2519 laboratory confirmed cases with a case-fatality rate of 34.3% have been reported. Approximately 84% of human cases have been reported in the tropical region of Saudi Arabia. The emergence of MERS-CoV has highlighted need for a rapid and accurate assay to triage patients with a suspected infection in a timely manner because of the lack of an approved vaccine or an effective treatment for MERS-CoV to prevent and control potential outbreaks. In this study, we present two rapid and visual nucleic acid assays that target the MERS-CoV UpE and N genes as a panel that combines reverse transcription recombinase polymerase amplification with a closed vertical flow visualization strip (RT-RPA-VF). This test panel was designed to improve the diagnostic accuracy through dual-target screening after referencing laboratory testing guidance for MERS-CoV. The limit of detection was 1.2×101 copies/µl viral RNA for the UpE assay and 1.2 copies/µl viral RNA for the N assay, with almost consistent with the sensitivity of the RT-qPCR assays. The two assays exhibited no cross-reactivity with multiple CoVs, including the bat severe acute respiratory syndrome related coronavirus (SARSr-CoV), the bat coronavirus HKU4, and the human coronaviruses 229E, OC43, HKU1 and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Furthermore, the panel does not require sophisticated equipment and provides rapid detection within 30 min. This panel displays good sensitivity and specificity and may be useful to rapidly detect MERS-CoV early during an outbreak and for disease surveillance.