Shared within-host SARS-CoV-2 variation in households (preprint)

Background: The limited variation observed among SARS-CoV-2 consensus sequences makes it difficult to reconstruct transmission linkages in outbreak settings. Previous studies have recovered variation within individual SARS-CoV-2 infections but have not yet measured the informativeness of within-host variation for transmission inference. Methods: We performed tiled amplicon sequencing on 307 SARS-CoV-2 samples from four prospective studies and combined sequence data with household membership data, a proxy for transmission linkage. Results: Consensus sequences from households had limited diversity (mean pairwise distance, 3.06 SNPs; range, 0-40). Most (83.1%, 255/307) samples harbored at least one intrahost single nucleotide variant (iSNV; median: 117; IQR: 17-208), when applying a liberal minor allele frequency of 0.5% and prior to filtering. A mean of 15.4% of within-host iSNVs were recovered one day later. Pairs in the same household shared significantly more iSNVs (mean: 1.20 iSNVs; 95% CI: 1.02-1.39) than did pairs in different households infected with the same viral clade (mean: 0.31 iSNVs; 95% CI: 0.28-0.34), a signal that increases with increasingly liberal thresholds. Conclusions: Although only a subset of within-host variation is consistently shared across likely transmission pairs, shared iSNVs may augment the information in consensus sequences for predicting transmission linkages.

Human KIR+CD8+ T cells target pathogenic T cells in Celiac disease and are active in autoimmune diseases and COVID-19 (preprint)

Previous reports show that Ly49+CD8+ T cells can suppress autoimmunity in mouse models of autoimmune diseases. Here we find a markedly increased frequency of CD8+ T cells expressing inhibitory Killer cell Immunoglobulin like Receptors (KIR), the human equivalent of the Ly49 family, in the blood and inflamed tissues of various autoimmune diseases. Moreover, KIR+CD8+ T cells can efficiently eliminate pathogenic gliadin-specific CD4+ T cells from Celiac disease (CeD) patients' leukocytes in vitro. Furthermore, we observe elevated levels of KIR+CD8+ T cells, but not CD4+ regulatory T cells, in COVID-19 and influenza-infected patients, and this correlates with disease severity and vasculitis in COVID-19. Expanded KIR+CD8+ T cells from these different diseases display shared phenotypes and similar T cell receptor sequences. These results characterize a regulatory CD8+ T cell subset in humans, broadly active in both autoimmune and infectious diseases, which we hypothesize functions to control self-reactive or otherwise pathogenic T cells.

Favipiravir for treatment of outpatients with asymptomatic or uncomplicated COVID-19: a double-blind randomized, placebo-controlled, phase 2 trial (preprint)

Background Favipiravir is an oral, RNA-dependent RNA polymerase inhibitor with in vitro activity against SARS-CoV2. Despite limited data, favipiravir is administered to patients with COVID-19 in several countries. Methods We conducted a phase 2 double-blind randomized controlled outpatient trial of favipiravir in asymptomatic or mildly symptomatic adults with a positive SARS-CoV2 RT-PCR within 72 hours of enrollment. Participants were randomized 1:1 to receive placebo or favipiravir (1800 mg BID Day 1, 800mg BID Days 2-10). The primary outcome was SARS-CoV-2 shedding cessation in a modified intention-to-treat (mITT) cohort of participants with positive enrollment RT-PCRs. Using SARS-CoV-2 deep sequencing, we assessed favipiravir’s impact on mutagenesis. Results From July 8, 2020 - March 23, 2021, we randomized 149 participants with 116 included in the mITT cohort. The participants’ mean age was 43 years (SD 12.5) and 57 (49%) were women. We found no difference in time to shedding cessation by treatment arm overall (HR 0.76 favoring placebo, 95% confidence interval [CI] 0.48 – 1.20) or in sub-group analyses (age, sex, high-risk comorbidities, seropositivity or symptom duration at enrollment). We observed no difference in time to symptom resolution (initial: HR 0.84, 95% CI 0.54 – 1.29; sustained: HR 0.87, 95% CI 0.52 – 1.45). We detected no difference in accumulation of transition mutations in the viral genome during treatment. Conclusions Our data do not support favipiravir use at commonly used doses in outpatients with uncomplicated COVID-19. Further research is needed to ascertain if higher doses of favipiravir are effective and safe for patients with COVID-19. Trial registration number NCT04346628 Summary In this phase 2 double-blind randomized controlled outpatient trial of favipiravir in asymptomatic or uncomplicated patients with COVID-19, we found no difference in time to shedding cessation or time to symptom resolution by treatment arm.

SARS-CoV-2 subgenomic RNA kinetics in longitudinal clinical samples (preprint)

BackgroundGiven the persistence of viral RNA in clinically recovered COVID-19 patients, subgenomic RNAs (sgRNA) have been reported as potential molecular viability markers for SARS-CoV-2. However, few data are available on their longitudinal kinetics, compared with genomic RNA (gRNA), in clinical samples. MethodsWe analyzed 536 samples from 205 patients with COVID-19 from placebo-controlled, outpatient trials of Peginterferon Lambda-1a (Lambda; n=177) and favipiravir (n=359). Nasal swabs were collected at three time points in the Lambda (Day 1, 4 and 6) and favipiravir (Day 1, 5, and 10) trials. N-gene gRNA and sgRNA were quantified by RT-qPCR. To investigate the decay kinetics in vitro, we measured gRNA and sgRNA in A549ACE2+ cells infected with SARS-CoV-2, following treatment with remdesivir or DMSO control. ResultsAt six days in the Lambda trial and ten days in the favipiravir trial, sgRNA remained detectable in 51.6% (32/62) and 49.5% (51/106) of the samples, respectively. Cycle threshold (Ct) values for gRNA and sgRNA were highly linearly correlated (Pearsons r=0.87) and the rate of increase did not differ significantly in Lambda (1.36 cycles/day vs 1.36 cycles/day; p = 0.97) or favipiravir (1.03 cycles/day vs 0.94 cycles/day; p=0.26) trials. From samples collected 15-21 days after symptom onset, sgRNA was detectable in 48.1% (40/83) of participants. In SARS-CoV-2 infected A549ACE2+ cells treated with remdesivir, the rate of Ct increase did not differ between gRNA and sgRNA. ConclusionsIn clinical samples and in vitro, sgRNA was highly correlated with gRNA and did not demonstrate different decay patterns to support its application as a viability marker. SummaryWe observed prolonged detection of subgenomic RNA in nasal swabs and equivalent decay rates to genomic RNA in both longitudinal nasal swabs and in remdesivir-treated A549ACE2+ cells infected with SARS-CoV-2. Taken together, these findings suggest that subgenomic RNA from SARS-CoV-2 is comparably stable to genomic RNA and that its detection is therefore not a more reliable indicator of replicating virus.

A repurposed, blood gene signature is associated with poor outcomes in SARS-CoV-2 (preprint)

Poor outcomes after SARS-CoV-2 infection are difficult to predict. Survivors may develop pulmonary fibrosis. We previously identified a 52-gene signature in peripheral blood, predictive of mortality in Idiopathic Pulmonary Fibrosis. In this study, we analyzed this signature in SARS-CoV-2 infected individuals and identified genomic risk profiles with significant differences in outcomes. Analysis of single cell expression data shows that monocytes, red blood cells, neutrophils and dendritic cells are the cellular source of the high risk gene signature.

The multidisciplinary nature of COVID-19 research (preprint)

Objective: We analyzed the scientific output after COVID-19 and contrasted it with studies published in the aftermath of seven epidemics/pandemics: Severe Acute Respiratory Syndrome (SARS), Influenza A virus H5N1 and Influenza A virus H1N1 human infections, Middle East Respiratory Syndrome (MERS), Ebola virus disease, Zika virus disease, and Dengue. Design/Methodology/Approach: We examined bibliometric measures for COVID-19 and the rest of studied epidemics/pandemics. Data were extracted from Web of Science, using its journal classification scheme as a proxy to quantify the multidisciplinary coverage of scientific output. We proposed a novel Thematic Dispersion Index (TDI) for the analysis of pandemic early stages. Results/Discussion: The literature on the seven epidemics/pandemics before COVID-19 has shown explosive growth of the scientific production and continuous impact during the first three years following each emergence or re-emergence of the specific infectious disease. A subsequent decline was observed with the progressive control of each health emergency. We observed an unprecedented growth in COVID-19 scientific production. TDI measured for COVID-19 (29,4) in just six months, was higher than TDI of the rest (7,5 to 21) during the first three years after epidemic initiation. Conclusions: COVID-19 literature showed the broadest subject coverage, which is clearly a consecuence of its social, economic, and political impact. The proposed indicator (TDI), allowed the study of multidisciplinarity, differentiating the thematic complexity of COVID-19 from the previous seven epidemics/pandemics. Originality/Value: The multidisciplinary nature and thematic complexity of COVID-19 research were successfully analyzed through a scientometric perspective.

Peginterferon Lambda-1a for treatment of outpatients with uncomplicated COVID-19: a randomized placebo-controlled trial (preprint)

Type III interferons have been touted as promising therapeutics in outpatients with coronavirus disease 2019 (COVID-19). We conducted a randomized placebo-controlled trial in 120 patients with mild to moderate COVID-19 to determine whether a single, 180 mcg subcutaneous dose of Peginterferon Lambda-1a (Lambda) could shorten the duration of viral shedding (primary endpoint) or symptoms (secondary endpoint, NCT04331899). In both the 60 patients receiving Lambda and the 60 receiving placebo, the median time to cessation of viral shedding was 7 days (hazard ratio [HR] = 0.81; 95% confidence interval [CI] 0.56 to 1.19). Symptoms resolved in 8 and 9 days in Lambda and placebo, respectively (HR 0.94; 95% CI 0.64 to 1.39). At enrollment; 41% of subjects were SARS-CoV-2 IgG seropositive; compared to placebo, lambda tended to delay shedding cessation in seronegatives (aHR 0.66, 95% CI 0.39-1.10) and to hasten shedding cessation in seropositives (aHR 1.58, 95% CI 0.88-2.86; p for interaction = 0.03). Liver transaminase elevations were more common in the Lambda vs. placebo arm (15/60 vs 5/60; p = 0.027). In this study, a single dose of subcutaneous Peginterferon Lambda-1a neither shortened the duration of SARS-CoV-2 viral shedding nor improved symptoms in outpatients with uncomplicated COVID-19.

N439K variant in spike protein may alter the infection efficiency and antigenicity of SARS-CoV-2 based on molecular dynamics simulation (preprint)

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), causing an outbreak of coronavirus disease 2019 (COVID-19), has been undergoing various mutations. The analysis of the structural and energetic effects of mutations on protein-protein interactions between the receptor binding domain (RBD) of SARS-CoV-2 and angiotensin converting enzyme 2 (ACE2) or neutralizing monoclonal antibodies will be beneficial for epidemic surveillance, diagnosis, and optimization of neutralizing agents. According to the molecular dynamics simulation, a key mutation N439K in the SARS-CoV-2 RBD region created a new salt bridge which resulted in greater electrostatic complementarity. Furthermore, the N439K-mutated RBD bound hACE2 with a higher affinity than wild-type, which may lead to more infectious. In addition, the N439K-mutated RBD was markedly resistant to the SARS-CoV-2 neutralizing antibody REGN10987, which may lead to the failure of neutralization. These findings would offer guidance on the development of neutralizing antibodies and the prevention of COVID-19.

Peginterferon Lambda-1a for treatment of outpatients with uncomplicated COVID-19: a randomized placebo-controlled trial (preprint)

Type III interferons have been touted as promising therapeutics in outpatients with coronavirus disease 2019 (COVID-19). We conducted a randomized placebo-controlled trial in 120 patients with mild to moderate COVID-19 to determine whether a single, 180 mcg subcutaneous dose of Peginterferon Lambda-1a (Lambda) could shorten the duration of viral shedding (primary endpoint) or symptoms (secondary endpoint, NCT04331899). In both the 60 patients receiving Lambda and 60 receiving placebo, the median time to cessation of viral shedding was 7 days (hazard ratio [HR] = 0.81; 95% confidence interval [CI] 0.56 to 1.19). Symptoms resolved in 8 and 9 days in Lambda and placebo, respectively (HR 0.94; 95% CI 0.64 to 1.39). At enrollment; 41% of subjects were SARS-CoV-2 IgG seropositive; compared to placebo, lambda tended to delay shedding cessation in seronegatives (aHR 0.66, 95% CI 0.39-1.10) and to hasten shedding cessation in seropositives (aHR 1.58, 95% CI 0.88-2.86; p for interaction = 0.03). Liver transaminase elevations were more common in the Lambda vs. placebo arm (15/60 vs 5/60; p = 0.027). In this study, a single dose of subcutaneous Peginterferon Lambda-1a neither shortened the duration of SARS-CoV-2 viral shedding nor improved symptoms in outpatients with uncomplicated COVID-19.