CoviRx: A User-Friendly Interface for Systematic Down-Selection of Repurposed Drug Candidates for COVID-19 (preprint)

Although various vaccines are now commercially available, they have not been able to stop the spread of COVID-19 infection completely. An excellent strategy to quickly get safe, effective, and affordable COVID-19 treatment is to repurpose drugs that are already approved for other diseases as adjuvants along with the ongoing vaccine regime. The process of developing an accurate and standardized drug repurposing dataset requires a considerable level of resources and expertise due to the commercial availability of an extensive array of drugs that could be potentially used to address the SARS-CoV-2 infection. To address this bottleneck, we created the CoviRx platform. CoviRx is a user-friendly interface that provides access to the data, which is manually curated for COVID-19 drug repurposing data. Through CoviRx, the data curated has been made open-source to help advance drug repurposing research. CoviRx also encourages users to submit their findings after thoroughly validating the data, followed by merging it by enforcing uniformity and integ-rity-preserving constraints. This article discusses the various features of CoviRx and its design principles. CoviRx has been designed so that its functionality is independent of the data it dis-plays. Thus, in the future, this platform can be extended to include any other disease X beyond COVID-19. CoviRx can be accessed at www.covirx.org.

Systematic Down-Selection of Repurposed Drug Candidates for COVID-19 (preprint)

SARS-CoV-2, is the cause of the COVID-19 pandemic which has claimed more than six million lives worldwide, devastating the economy and overwhelming healthcare systems globally. The development of new drug molecules and vaccines has played a critical role in managing the pandemic; however, new variants of concern still pose a significant threat as the current vaccines cannot prevent all infections. This situation calls for the collaboration of biomedical scientists and healthcare workers across the world. Repurposing approved drugs is an effective way of fast-tracking new treatments for recently emerged diseases. To this end, we have assembled and curated a database consisting of 7817 compounds from the Compounds Australia Open Drug collection. We developed a set of eight filters based on indicators of efficacy and safety that were applied sequentially to down-select drugs that showed promise for drug repurposing efforts against SARS-CoV-2. Considerable effort was made to evaluate approximately 14000 assay data points for SARS-CoV-2 FDA/TGA-approved drugs and provide an average activity score for 3539 compounds. The filtering process identified 12 FDA approved molecules with established safety profiles that have a plausible mechanism for treating COVID-19 disease. The methodology developed in our study provides a template for prioritising repurposable drug candidates that are safe, efficacious, and cost-effective for the treatment of COVID-19, long COVID, or any other future disease. We present our database in an easy-to-use interactive interface (CoviRx, https://www.covirx.org/) that was also developed to enable scientific community to access to the data of over 7000 potential drugs and to implement alternative prioritisation and down-selection strategies.

Secondary infections modify the overall course of hospitalized COVID-19 patients: A retrospective study from a network of hospitals across North India (preprint)

IntroductionSARS-CoV-2 infection increases the risk of secondary bacterial and fungal infections and contributes to adverse outcomes. The present study was undertaken to get better insights into the extent of secondary bacterial and fungal infections in Indian hospitalized patients and to assess how these alter the course of COVID-19 so that the control measures can be suggested. MethodsThis is a retrospective, multicentre study where data of all RT-PCR positive COVID-19 patients was accessed from Electronic Health Records (EHR) of a network of 10 hospitals across 5 North Indian states, admitted during the period from March 2020 to July 2021.The data included demographic profile of patients, clinical characteristics, laboratory parameters, treatment modalities, and outcome in those with secondary infections (SIs) and those without SIs. Spectrum of SIS was also studied in detail. ResultsOf 19852 RT-PCR positive SARS-CO2 patients admitted during the study period, 1940 (9.8%) patients developed SIs. Patients with SIs were 8 years older on average (median age 62.6 years versus 54.3 years; P<0.001) than those without SIs. The risk of SIs was significantly (p < 0.001) associated with age, severity of disease at admission, diabetes, ICU admission, and ventilator use. The most common site of infection was urinary tract infection (UTI) (41.7%), followed by blood stream infection (BSI) (30.8%), sputum/BAL/ET fluid (24.8%), and the least was pus/wound discharge (2.6%). As many as 13.4% had infections with more than organism and 34.1% patients had positive cultures from more than one site. Gram negative bacilli (GNB) were the commonest organisms (63.2%), followed by Gram positive cocci (GPC) (19.6%) and fungus (17.3%). Most of the patients with SIs were on multiple antimicrobials - the most commonly used were the BL-BLI for GNBs (76.9%) followed by carbapenems (57.7%), cephalosporins (53.9%) and antibiotics carbapenem resistant entreobacteriace (47.1%). The usage of emperical antibiotics for GPCs was in 58.9% and of antifungals in 56.9% of cases, and substantially more than the results obtained by culture. The average stay in hospital for patients with SIs was twice than those without SIs (median 13 days versus 7 days). The overall mortality in the group with SIs (40.3%) was more than 8 times of that in those without SIs (4.6%). Only 1.2% of SI patients with mild COVID-19 at presentation died, while 17.5% of those with moderate disease and 58.5% of those with severe COVID-19 died (P< 0.001). The mortality was highest in those with BSI (49.8%), closely followed by those with HAP (47.9%), and then UTI and SSTI (29.4% each). The mortality rate where only one microorganism was identified was 37.8% and rose to 56.3% in those with more than one microorganism. The mortality in cases with only one site of infection was 28.8%, which steeply rose to 62.5% in cases with multiple sites of infection. The mortality in diabetic patients with SIs was 45.2% while in non-diabetics it was 34.3% (p < 0.001). ConclusionsSecondary bacterial and fungal infections can complicate the course of almost 10% of COVID-19 hospitalised patients. These patients tend to not only have a much longer stay in hospital, but also a higher requirement for oxygen and ICU care. The mortality in this group rises steeply by as much as 8 times. The group most vulnerable to this complication are those with more severe COVID-19 illness, elderly, and diabetic patients. Varying results in different studies suggest that a region or country specific guideline be developed for appropriate use of antibiotics and antifungals to prevent their overuse in such cases. Judicious empiric use of combination antimicrobials in this set of vulnerable COVID-19 patients can save lives.

Covid-19 Associated Hepatitis in children (CACH) during the second wave of SARS-CoV-2 infections in Central India: Is it a complication or transient phenomenon. (preprint)

Background: Besides Covid-19, SARS-CoV-2 infection has been associated with Multiple Inflammatory Syndrome in children (MIS-C). However, a unique presentation of a transient form of hepatitis in pediatric age group occurring subsequent to the asymptomatic SARS-CoV-2 infection is yet to be reported in children. Presently the clinical work, temporal association and characteristics different than MIS-C of the cases of CAHC is being dealt with. Methods: As a retrospective and follow up observational study we reviewed all pediatric patients presenting with acute hepatitis during the study period from April 2021 to mid- June 2021. We observed a sudden rise of features of hepatitis in a group of pediatric patients during the second wave of SARS CoV-2 infections, where children or adolescents developing sudden onset acute hepatitis with no history of pre-existing liver disease in the absence of familiar etiology of acute hepatitis and with a recent 3-6 week history of RT-PCR positivity or a retrospectively proven Covid-19 infection with high titer SARS CoV-2 antibodies. Such patients had asymptomatic Covid-19 infection, while another very small group (n=8) patients having findings similar to MIS-C was identified with protracted and grave presentation, having multiple organ involvement along with Covid-19 diagnosis. Routine lab workup along with viral serology of acute hepatitis was performed in all such patients. These patients were negative for Hepatitis A, B, C and E but had high titer of SARS CoV-2 antibodies. Results: Among 33 patients who presented with hepatitis, 25 patients showed unique features of CAHC, they had hepatitis only. These patients did not have any typical Covid-19 symptoms, had normal to borderline inflammatory markers, with admission to general care wards, all recovered on supportive treatment without any complications or mortality. Whereas patients with MIS-C (n=8) required admission to critical care, they had high level of inflammatory markers and 3 (37.5%) had an adverse outcome. Conclusion: With emergence of newer variants of concern such as the Delta variant which caused the massive wave of Covid-19 in India, with varied presentations, CAHC is one of them. Such new entities need to be timely identified and differentiated from other types of emerging syndromes in children for appropriate management.

Differentials in the characteristics of COVID-19 cases in Wave-1 and Wave-2 admitted to a network of hospitals in North India (preprint)

Second wave of COVID 19 pandemic in India came with unexpected quick speed and intensity, creating an acute shortage of beds, ventilators, and oxygen at the peak of occurrence. This may have been partly caused by emergence of new variant delta. Clinical experience with the cases admitted to hospitals suggested that it is not merely a steep rise in cases but also possibly the case profile is different. This study was taken up to investigate the differentials in the characteristics of the cases admitted in the second wave versus those admitted in the first wave. Records of a total of 14398 cases admitted in the first wave (2020) to our network of hospitals in north India and 5454 cases admitted in the second wave (2021) were retrieved, making it the largest study of this kind in India. Their demographic profile, clinical features, management, and outcome was studied. Age sex distribution of the cases in the second wave was not much different from those admitted in the first wave but the patients with comorbidities and those with greater severity had larger share. Level of inflammatory markers was more adverse. More patients needed oxygen and invasive ventilation. ICU admission rate remained nearly the same. On the positive side, readmissions were lower, and the duration of hospitalization was slightly less. Usage of drugs like remdesivir and IVIG was higher while that of favipiravir and tocilizumab was lower. Steroid and anticoagulant use remained high and almost same during the two waves. More patients had secondary bacterial and fungal infections in Wave 2. Mortality increased by almost 40% in Wave 2, particularly in the younger patients of age less than 45 years. Higher mortality was observed in those admitted in wards, ICU, with or without ventilator support and those who received convalescent plasma. No significant demographic differences in the cases in these two waves, indicates the role of other factors such as delta variant and late admissions in higher severity and more deaths. Comorbidity and higher secondary bacterial and fungal infections may have contributed to increased mortality.

UVA radiation could be a significant contributor to sunlight inactivation of SARS-CoV-2 (preprint)

Past experiments demonstrated SARS-CoV-2 inactivation by simulated sunlight; models have considered exclusively mechanisms involving UVB acting directly on RNA. However, UVA inactivation has been demonstrated for other enveloped RNA viruses, through indirect mechanisms involving the suspension medium. We propose a model combining UVB and UVA inactivation for SARS-CoV-2, which improves predictions by accounting for effects associated with the medium. UVA sensitivities deduced for SARS-CoV-2 are consistent with data for SARS-CoV-1 under UVA only. This analysis calls for experiments to separately assess effects of UVA and UVB in different media, and for including UVA in inactivation models. Key words: SARS-CoV-2, COVID-19, environmental persistence, sunlight, UVA, UVB, modeling, inactivation methods, photobiology

Analysis of SARS-CoV-2 genomes from across Africa reveals potentially clinically relevant mutations. (preprint)

SARS-CoV-2 is a betacoronavirus, the etiologic agent of the novel Coronavirus disease 2019 (COVID-19). In December 2019, an outbreak of COVID-19 began in Wuhan province of the Hubei district in China and rapidly spread across the globe. On March 11th, 2020, the World Health Organization officially designated COVID-19 as a pandemic. Across the continents and specifically in Africa, all index cases were travel related. Thus, it is crucial to compare COVID-19 genome sequences from the African continent with sequences from COVID-19 hotspots (including China, Brazil, Italy, United State of America and the United Kingdom). To identify if there are distinguishing mutations in the African SARS-CoV-2 genomes compared to genomes from other countries, including disease hotspots, we conducted in silico analyses and comparisons. Complete African SARS-CoV-2 genomes deposited in GISAID and NCBI databases as of June 2020 were downloaded and aligned with genomes from Wuhan, China and other SARS-CoV-2 hotspots. Using phylogenetic analysis and amino acid sequence alignments of the spike and replicase (NSP12) proteins, we searched for possible targets for vaccine coverage or potential therapeutic agents. Our results showed a similarity between the African SARS-CoV-2 genomes and genomes in countries including China, Brazil, France, the United Kingdom, Italy, France and the United States of America. This study shows for the first time, an in-depth analysis of the SARS-CoV-2 landscape across Africa and will potentially provide insights into specific mutations to relevant proteins in the SARS-CoV-2 genomes in African populations.

A prefusion SARS-CoV-2 spike RNA vaccine is highly immunogenic and prevents lung infection in non-human primates (preprint)

To contain the coronavirus disease 2019 (COVID-19) pandemic, a safe and effective vaccine against the new severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is urgently needed in quantities sufficient to immunise large populations. In this study, we report the design, preclinical development, immunogenicity and anti-viral protective effect in rhesus macaques of the BNT162b2 vaccine candidate. BNT162b2 contains an LNP-formulated nucleoside-modified mRNA that encodes the spike glycoprotein captured in its prefusion conformation. After expression of the BNT162b2 coding sequence in cells, approximately 20% of the spike molecules are in the one-RBD up, two-RBD down state. Immunisation of mice with a single dose of BNT162b2 induced dose level-dependent increases in pseudovirus neutralisation titers. Prime-boost vaccination of rhesus macaques elicited authentic SARS-CoV-2 neutralising geometric mean titers 10.2 to 18.0 times that of a SARS-CoV-2 convalescent human serum panel. BNT162b2 generated strong TH1 type CD4+ and IFNy+ CD8+ T-cell responses in mice and rhesus macaques. The BNT162b2 vaccine candidate fully protected the lungs of immunised rhesus macaques from infectious SARS-CoV-2 challenge. BNT162b2 is currently being evaluated in a global, pivotal Phase 2/3 trial (NCT04368728).

In vitro study of BromAc on SARS-CoV-2 spike and envelope proteins shows synergy and disintegration at modest concentrations (preprint)

Objectives: SARS-CoV-2 infection is the cause of a worldwide pandemic, currently with limited therapeutic options. It is characterised by being highly contagious and nasal mucosa appears to be the primary site with subsequent spread to the lungs and elsewhere. BromAc (Bromelain & Acetylcysteine) has been described to disrupt glycoproteins by the synchronous breakage of glycosidic linkages and disulphide bonds. The spike protein of SARS-CoV-2 is an attractive target as it is essential for binding to the ACE2 receptor in host cells and is formed of glycoprotein and disulphide bridges for stabilisation. Hence, we sought to determine whether BromAc has activity on the spike and envelope protein specific to SARS-CoV-2 virus. Design: Gel electrophoresis analysis was carried out on recombinant spike and envelope proteins that were treated with a range of concentrations of single agents and BromAc. For UV analysis of disulfide bonds reduction, both spike and envelope protein were treated with Acetylcysteine with the determination of loss of disulfide bonds. Results: Recombinant spike and envelope SARS-CoV-2 protein were fragmented by BromAc whilst single agents had minimal effect. Spike and envelope proteins disulphide bonds were reduced by Acetylcysteine. Conclusion: BromAc disintegrates the spike and envelope protein from SARS-CoV-2 and may render it non-infective. In vitro tests on live virus have been encouraging and clinical testing through nasal administration in patients with early SARS-CoV-2 infection is imminent.

Convalescent plasma in the management of moderate COVID-19 in India: An open-label parallel-arm phase II multicentre randomized controlled trial (PLACID Trial) (preprint)

ObjectivesConvalescent plasma (CP) as a passive source of neutralizing antibodies and immunomodulators is a century-old therapeutic option used for the management of viral diseases. We investigated its effectiveness for the treatment of COVID-19. DesignOpen-label, parallel-arm, phase II, multicentre, randomized controlled trial. SettingThirty-nine public and private hospitals across India. ParticipantsHospitalized, moderately ill confirmed COVID-19 patients (PaO2/FiO2: 200-300 or respiratory rate > 24/min and SpO2 [≤] 93% on room air). InterventionParticipants were randomized to either control (best standard of care (BSC)) or intervention (CP + BSC) arm. Two doses of 200 mL CP was transfused 24 hours apart in the intervention arm. Main Outcome MeasureComposite of progression to severe disease (PaO2/FiO2< 100) or all-cause mortality at 28 days post-enrolment. ResultsBetween 22nd April to 14th July 2020, 464 participants were enrolled; 235 and 229 in intervention and control arm, respectively. Composite primary outcome was achieved in 44 (18.7%) participants in the intervention arm and 41 (17.9%) in the control arm [aOR: 1.09; 95% CI: 0.67, 1.77]. Mortality was documented in 34 (13.6%) and 31 (14.6%) participants in intervention and control arm, respectively [aOR) 1.06 95% CI: -0.61 to 1.83]. InterpretationCP was not associated with reduction in mortality or progression to severe COVID-19. This trial has high generalizability and approximates real-life setting of CP therapy in settings with limited laboratory capacity. A priori measurement of neutralizing antibody titres in donors and participants may further clarify the role of CP in management of COVID-19. Trial registrationThe trial was registered with Clinical Trial Registry of India (CTRI); CTRI/2020/04/024775.

Antibody binding to SARS-CoV-2 S glycoprotein correlates with, but does not predict neutralization (preprint)

Convalescent plasma from SARS-CoV-2 infected individuals and monoclonal antibodies were shown to potently neutralize viral and pseudoviral particles carrying the S glycoprotein. However, a non-negligent proportion of plasma samples from infected individuals as well as S-specific monoclonal antibodies were reported to be non-neutralizing despite efficient interaction with the S glycoprotein in different biochemical assays using soluble recombinant forms of S or when expressed at the cell surface. How neutralization relates to binding of S glycoprotein in the context of viral particles remains to be established. Here we developed a pseudovirus capture assay (VCA) to measure the capacity of plasma samples or antibodies immobilized on ELISA plates to bind to membrane-bound S glycoproteins from SARS-CoV-2 expressed at the surface of lentiviral particles. By performing VCA and neutralization assays we observed a strong correlation between these two parameters. However, while we found that plasma samples unable to capture viral particles did not neutralize, capture did not guarantee neutralization, indicating that the capacity of antibodies to bind to the S glycoprotein at the surface of viral particles is required but not sufficient to mediate neutralization. Altogether, our results highlights the importance of better understanding the inactivation of S by plasma and neutralizing antibodies.

Interaction of human ACE2 to membrane-bound SARS-CoV-1 and SARS-CoV-2 S glycoproteins (preprint)

A novel severe acute respiratory (SARS)-like coronavirus (SARS-CoV-2) is responsible for the current global coronavirus disease 2019 (COVID-19) pandemic, infecting millions of people and causing hundreds of thousands of deaths. The viral entry of SARS-CoV-2 depends on an interaction between the receptor binding domain of its trimeric Spike glycoprotein and the human angiotensin converting enzyme 2 (ACE2) receptor. A better understanding of the Spike/ACE2 interaction is still required to design anti-SARS-CoV-2 therapeutics. Here, we investigated the degree of cooperativity of ACE2 within both the SARS-CoV-2 and the closely related SARS-CoV-1 membrane-bound S glycoproteins. We show that there exist differential inter-protomer conformational transitions between both Spike trimers. Interestingly, the SARS-CoV-2 spike exhibits a positive cooperativity for monomeric soluble ACE2 binding when compared to the SARS-CoV-1 spike, which might have more structural restrains. Our findings can be of importance in the development of therapeutics that block the Spike/ACE2 interaction.