RNA Clearance Research Articles

Macrophage Depletion Reactivates Fecal Virus Shedding following Resolution of Acute Hepatitis A in Ifnar1-/- Mice.

Although hepatitis A virus (HAV) is associated only with acute hepatitis in humans, HAV RNA persists within the liver for months following resolution of liver inflammation and cessation of fecal virus shedding in chimpanzees and murine models of hepatitis A. Here, we confirm striking differences in the kinetics of HAV RNA clearance from liver versus serum and feces in infected Ifnar1-/- mice and investigate the nature of viral RNA persisting in the liver following normalization of serum alanine aminotransferase (ALT) levels. Fecal shedding of virus produced in hepatocytes declined >3,000-fold between its peak at day 14 and day 126, whereas intrahepatic HAV RNA declined only 32-fold by day 154. Viral RNA was identified within hepatocytes 3 to 4 months after inoculation and was associated with membranes, banding between 1.07 and 1.14 g/cm3 in isopycnic iodixanol gradients. Gradient fractions containing HAV RNA demonstrated no infectivity when inoculated into naive mice but contained neutralizing anti-HAV antibody. Depleting CD4+ or CD8+ T cells at this late point in infection had no effect on viral RNA abundance in the liver, whereas clodronate-liposome depletion of macrophages between days 110 and 120 postinoculation resulted in a striking recrudescence of fecal virus shedding and the reappearance of viral RNA in serum coupled with reductions in intra-hepatic Ifnγ, Tnfα, Ccl5, and other chemokine transcripts. Our data suggest that replication-competent HAV RNA persists for months within the liver in the presence of neutralizing antibody following resolution of acute hepatitis in Ifnar1-/- mice and that macrophages play a key role in viral control late in infection. IMPORTANCE HAV RNA persists in the liver of infected chimpanzees and interferon receptor-deficient Ifnar1-/- mice for many months after neutralizing antibodies appear, virus has been cleared from the blood, and fecal virus shedding has terminated. Here, we show this viral RNA is located within hepatocytes and that the depletion of macrophages months after the resolution of hepatic inflammation restores fecal virus shedding and circulating viral RNA. Our study identifies an important role for macrophages in virus control following resolution of acute hepatitis A in Ifnar1-/- mice and may have relevance to relapsing hepatitis A in humans.

The Persistence Time of SARS-CoV-2 RNA in Hospitalized COVID-19 Patients: A Prospective Study.

In late December 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV2), the causative agent of coronavirus disease 2019 (COVID-19), spread to almost all countries worldwide. The outbreak of this virus has been confirmed on 19th February, 2020, in Iran. The aim of this study was to investigate the time of viral RNA clearance in swab and serum samples of COVID-19 patients having received different medications. We also evaluated different factors that may affect viral RNA persistence in patients infected by SARS-CoV-2. In March 2020, twenty-one hospitalized COVID-19 patients participated in this prospective study. All patients received antiviral agents in their routine care. Throat swabs and blood samples were obtained from all patients in different intervals, including day 3 or 5, day 7, day 10, and finally, 14 days after the first positive real-time RT-PCR (rRT-PCT) test. The median time from the symptom onset (SO) to the first negative rRT-PCR results for throat swabs and serum samples of COVID-19 patients was 18 and 14 days, respectively. These times were more significant in patients with lymphopenia, oxygen saturation ≤ 90%, and comorbidity. This preliminary study highlights that SASR-CoV-2 RNA was not detectable in the upper respiratory tract for longer than three weeks. In addition, SARS-CoV-2 may persist for a long period of time in the respiratory than in the serum samples. This study supports the idea that in limited resource settings, the patients should be tested earlier than three weeks for discharge management.

Clinical characteristics and immune profile alterations in vaccinated individuals with breakthrough Delta SARS-CoV-2 infections

Despite timely immunization programs, and efficacious vaccines conveying protection against SARS-CoV-2 infection, breakthrough infections in vaccinated individuals have been reported. The Delta variant of concern (VOC) outbreak in Guangzhou resulted in local transmission in vaccinated and non-vaccinated residents, providing a unique opportunity to study the protective effects of the inactivated vaccines in breakthrough infection. Here, we find that the 2-dose vaccinated group has similar peak viral titers and comparable speeds of viral RNA clearance to the non-vaccinated group but accelerated viral suppression in the middle course of the disease. We quantitatively demonstrate that peak viral pneumonia is significantly mitigated in the 2-dose vaccine group (median 0.298%) compared with the non-vaccinated (5.77%) and 1-dose vaccine (3.34%) groups. Pneumonia absorbance is approximately 6 days ahead in the 2-dose group (median 10 days) than in the non-vaccinated group (16 days) (p = 0.003). We also observe reduced cytokine inflammation and markedly undisturbed gene transcription profiles of peripheral blood mononuclear cells (PBMCs) in the 2-dose group. In short, our study demonstrates that prior vaccination substantially restrains pneumonia development, reduces cytokine storms, and facilitates clinical recovery.

Molnupiravir - the First Oral Antiviral for COVID-19: A Literature Review

The COVID-19 pandemic is still an unresolved global health concern, although half of the world's population has been vaccinated. The pharmaceutical industries are still struggling to develop effective antivirals against SARS-CoV-2. Molnupiravir is a new oral antiviral with antiviral properties by targeting coronavirus RNA. This literature review aims to describe the mechanism of action, efficacy, and safety of molnupiravir based on published preclinical and clinical studies for COVID-19 treatment. Relevant studies were collected by electronic databases, including Google Scholar, PubMed, and Science Direct. The inclusion criteria were preclinical and clinical trials related to molnupiravir as an antiviral for the COVID-19 treatment published in December 2019 to January 2022. Preclinical trials demonstrated therapeutic and prophylactic properties against SARS-CoV-2 in cell culture and animal models. Molnupiravir is currently under the emergency use authorization from the FDA to treat COVID-19. Its potent and broad antiviral activity is demonstrated through a mechanism of error catastrophe that causes coronavirus RNA mutagenesis. The published clinical trials have shown that molnupiravir is well-absorbed, well-tolerated, and has relatively mild side effects such as headache, nausea, and diarrhea with a minimal incidence at a dose of 800 mg twice daily. Time to viral RNA clearance was significantly decreased in patients administered molnupiravir 800 mg compared to those who administered placebo (14 days vs 15 days, P value=0,013). Molnupiravir is a promising oral antiviral that can reduce the incidence of COVID-19 hospitalization or death. Further clinical trials regarding its efficacy for severe symptoms and other clinical aspects such as drug interactions and contraindications are still needed.

No effect of remdesivir or betamethasone on upper respiratory tract SARS-CoV-2 RNA kinetics in hospitalised COVID-19 patients: a retrospective observational study

Background The viral kinetics of SARS-CoV-2 has been considered clinically important. While remdesivir and corticosteroids are recommended for COVID-19 patients requiring oxygen support, there is a limited number of published reports on viral kinetics in hospitalised patients with COVID-19 treated with remdesivir or corticosteroids. Methods We conducted a retrospective study by collecting longitudinal samples from the nasopharynx/throat of 123 hospitalised patients (median age 55 years, 74% male) with COVID-19, to evaluate the effects of remdesivir and corticosteroid treatment on viral RNA levels. The subjects were divided into four groups: those receiving remdesivir (n = 25), betamethasone (n = 41), both (n = 15), or neither (n = 42). Time to viral RNA clearance was analysed using Kaplan-Meier plots, categorical data were analysed using Fisher’s exact test, and Kruskal-Wallis for continuous data. Viral RNA decline rate was analysed using a mixed effect model. Results We found no significant difference in SARS-CoV-2 RNA decline rate or time to SARS-CoV-2 RNA clearance between the groups. Moreover, clinical status at baseline was not correlated with time to viral clearance. Conclusions Since SARS-CoV-2 RNA kinetics was not affected by treatment, repeated sampling from the upper respiratory tract cannot be used to evaluate treatment response.

Antiviral Efficacy and Safety of Molnupiravir Against Omicron Variant Infection: A Randomized Controlled Clinical Trial

Background: The rapid worldwide spread of the Omicron variant of SARS-CoV-2 has unleashed a new wave of COVID-19 outbreaks. The efficacy of molnupiravir, an approved drug, is still unknown in patients infected with the Omicron variant. Objective: Evaluated the antiviral efficacy and safety of molnupiravir in patients infected with SARS-CoV-2 Omicron variant, with symptom duration within 5 days. Methods: We conducted a randomized, controlled trial involving patients with mild or moderate COVID-19. Patients were randomized to orally receive molnupiravir (800 mg) plus basic treatment or only basic treatment for 5 days (BID). The antiviral efficacy of the drug was evaluated using reverse transcriptase polymerase chain reaction. Results: Results showed that the time of viral RNA clearance (primary endpoint) was significantly decreased in the molnupiravir group (median, 9 days) compared to the control group (median, 10 days) (Log-Rank p = 0.0092). Of patients receiving molnupiravir, 18.42% achieved viral RNA clearance on day 5 of treatment, compared to the control group (0%) (p = 0.0092). On day 7, 40.79%, and 6.45% of patients in the molnupiravir and control groups, respectively, achieved viral RNA clearance (p = 0.0004). In addition, molnupiravir has a good safety profile, and no serious adverse events were reported. Conclusion: Molnupiravir significantly accelerated the SARS-CoV-2 Omicron RNA clearance in patients with COVID-19. Clinical Trial Registration: [chictr.org.cn], identifier [ChiCTR2200056817].

Resistant-Associated Substitutions Do Not Affect HCV RNA and HCV Core Antigen Clearance During Direct-Acting Antiviral Agent Treatment in a Real-World Setting.

BackgroundSince oral direct-acting antiviral agents (DAAs) became available, the global hepatitis C treatment situation has undergone tremendous changes. However there are still many issues worthy of attention in treatment.MethodsWe selected 53 HCV-infected patients who were treated and followed up in the Peking University First Hospital from December 2017 to January 2021 to detect the RASs in HCV. Pearson correlation analysis was used to analyze HCV RNA and HCV cAg, the Fisher exact test and chi-square test was used to compare the effects of RASs on the rate of decline of HCV RNA and HCV core antigen (cAg) during DAA treatment.ResultsThe RASs and its prevalence on the NS3 are mainly Y56F 2.56% (1/39), Q80K 23.08% (9/39), S122G 71.79% (28/39), and V170I 38.46% (15/39). On the NS5A were R30Q 10.53% (4/38), P32A 5.26% (2/38), P58S 2.63% (1/39), and Y93H 21.05% (8/38). On NS5B were C316N 71.05% (27/38), C451H 2.63% (1/38), and I585C 2.63% (1/38). There was no significant correlation between the RASs (Y93H, V179I, Q80K, S122G, C316N) and HCV genotype (p > 0.05). The baseline serum HCV RNA and HCV cAg had a significant medium-degree correlation (r = 0.601, p = 0.002). After 1 week of DAA treatment was weak correlation (r = 0.413, p = 0.032). Q80K, S122G, V170I, Y93H, and C316N had no effect on the clearance of HCV RNA and HCV cAg within the first week of DAA treatment (p>0.05).ConclusionThe HCV genotype may have a limited impact on the presence of the five RASs (Y93H, V179I, Q80K, S122G, and C316N) as shown in this study. HCV RNA and HCV cAg have a correlation, especially at baseline is the highest; the appearance of some RASs has no effect on DAA treatment in most chronic hepatitis C patients.

Mettl3 downregulation in germinal vesicle oocytes inhibits mRNA decay and the first polar body extrusion during maturation†.

In oocytes, mRNA decay is essential for maturation and subsequent events, such as maternal-zygotic transition, zygotic genomic activation, and embryo development. Reversible N6-methyladenosine RNA methylation directly regulates transcription, pre-mRNA splicing, mRNA export, mRNA stability, and translation. Here, we identified that downregulation of N6-methyladenosine modification by microinjecting a methyltransferase-like 3 (Mettl3)-specific small interfering RNA into mouse germinal vesicle oocytes led to defects in meiotic spindles and the first polar body extrusion during maturation in vitro. By further quantitative real-time polymerase chain reaction and Poly(A)-tail assay analysis, we found that N6-methyladenosine methylation mainly acts by reducing deadenylation of mRNAs mediated by the carbon catabolite repression 4-negative on TATA less system, thereby causing mRNA accumulation in oocytes. Meanwhile, transcriptome analysis of germinal vesicle oocytes revealed the downregulation of transcripts of several genes encoding ribosomal subunits proteins in the Mettl3 small interfering RNA-treated group, suggesting that N6-methyladenosine modification might affect translation. Together, our results indicate that RNA methylation accelerates mRNA decay, confirming the critical role of RNA clearance in oocyte maturation.

Detectable Duration of Viable SARS-CoV-2, Total and Subgenomic SARS-CoV-2 RNA in Noncritically Ill COVID-19 Patients: a Prospective Cohort Study.

ABSTRACTDetermination of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infectivity is important in guiding the infection control and differentiating between reinfection and persistent viral RNA. Although viral culture is the gold standard to determine viral infectivity, the method is not practical. We studied the kinetics of SARS-CoV-2 total RNAs and subgenomic RNAs (sgRNAs) and their potential role as surrogate markers of viral infectivity. The kinetics of SARS-CoV-2 sgRNAs compared to those of the culture and total RNA shedding in a prospective cohort of patients diagnosed with coronavirus disease 2019 (COVID-19) were investigated. A total of 260 nasopharyngeal swabs from 36 patients were collected every other day after entering the study until the day of viral total RNA clearance, as measured by reverse transcription PCR (RT-PCR). Time to cessation of viral shedding was in order from shortest to longest: by viral culture, sgRNA RT-PCR, and total RNA RT-PCR. The median time (interquartile range) to negativity of viral culture, subgenomic N transcript, and N gene were 7 (5 to 9), 11 (9 to 16), and 18 (13 to 21) days, respectively (P < 0.001). Further analysis identified the receipt of steroid as the factors associated with longer duration of viral infectivity (hazard ratio, 3.28; 95% confidence interval, 1.02 to 10.61; P = 0.047). We propose the potential role of the detection of SARS-CoV-2 subgenomic RNA as the surrogate marker of viral infectivity. Patients with negative subgenomic N RNA RT-PCR could be considered for ending isolation.IMPORTANCE Our study, combined with existing evidence, suggests the feasibility of the use of subgenomic RNA RT-PCR as a surrogate marker for SARS-CoV-2 infectivity. The kinetics of SARS-CoV-2 subgenomic RNA should be further investigated in immunocompromised patients.

High content screening and proteomic analysis identify a kinase inhibitor that rescues pathological phenotypes in a patient-derived model of Parkinson\u2019s disease

Combining high throughput screening approaches with induced pluripotent stem cell (iPSC)-based disease modeling represents a promising unbiased strategy to identify therapies for neurodegenerative disorders. Here we applied high content imaging on iPSC-derived neurons from patients with familial Parkinson’s disease bearing the G209A (p.A53T) α-synuclein (αSyn) mutation and launched a screening campaign on a small kinase inhibitor library. We thus identified the multi-kinase inhibitor BX795 that at a single dose effectively restores disease-associated neurodegenerative phenotypes. Proteomics profiling mapped the molecular pathways underlying the protective effects of BX795, comprising a cohort of 118 protein-mediators of the core biological processes of RNA metabolism, protein synthesis, modification and clearance, and stress response, all linked to the mTORC1 signaling hub. In agreement, expression of human p.A53T-αSyn in neuronal cells affected key components of the mTORC1 pathway resulting in aberrant protein synthesis that was restored in the presence of BX795 with concurrent facilitation of autophagy. Taken together, we have identified a promising small molecule with neuroprotective actions as candidate therapeutic for PD and other protein conformational disorders.

Estimate and determinants of SARS-CoV-2 RNA clearance time among non-severe COVID-19 patients.

ABSTRACTObjectives:To estimate SARS-CoV-2 RNA clearance time among non-severe COVID-19 patients and explore factors associated with delayed negative conversion.Methods:A retrospective cohort study was conducted at the COVID-19 unit of a tertiary care center in the Western region of Saudi Arabia. Reverse transcriptase-polymerase chain reaction (RT-PCR) confirmed COVID-19 patients diagnosed between April 1 and June 30, 2020, were considered. The primary outcome was the time (days) from disease onset to first negative RT-PCR, which was analyzed using Kaplan–Meier and Cox regression survival methods. Demographic data, clinical history, baseline clinical, radiological and laboratory findings and management, and outcome data were collected and analyzed as factors associated with the viral RNA clearance time.Results:One hundred and forty-four patients were included. The mean (standard deviation [SD]) age was 36.93 (14.41) years, 50.7% were females, and 45.1% were healthcare workers. COVID19 was asymptomatic, mild and moderate in 11.1%, 71.5% and 17.4% of the participants, respectively. Fever (59.4%) and cough (58.0%) were the dominant onset symptoms. The mean viral RNA clearance time was 22.9 days (SD = 8.6; 95% confidence interval [CI] = 21.5–24.3 days). Extended clearance time was associated with older age (mean = 24.0 vs. 22.0 days; log-rank = 0.037), married status (23.2 vs. 22.6 days; log-rank = 0.021), working in health sector (24.2 vs. 21.8 days; log-rank = 0.006), and having a chronic disease (24.8 vs. 21.9 days; log-rank = 0.028), compared to their counterparts, respectively. In the adjusted model, the job sector was the only factor that was independently associated with clearance time. Non-healthcare sector showed hazard ratio 1.8 (95% CI = 1.3–2.7; log-rank = 0.002) with reference to healthcare sector.Conclusion:SARS-CoV-2 RNA clearance time is likely to be longer in non-severe COVID-19 patients, representing an additional risk for the virus dissemination among the community and calling for higher caution among the population.

Comparison of Clinical Characteristics and Outcomes of Hospitalized Patients Infected with the D614G Strain or Alpha Variant of COVID-19 in Taiwan: A Multi-Center Cohort Study

Objective: Direct comparison of the clinical traits of coronavirus disease 2019 (COVID-19) in strain D614G, which originated from Wuhan, China, and the Alpha variant, which contains 17 mutations, infected patients could help physicians distinguish between strains and make clinical decisions accordingly. This study sought to compare the clinical characteristics and outcomes of the D614G strain and Alpha variant of SARS-COV-2 and identify the predictors for viral RNA clearance and in-hospital mortality in patients with COVID-19. Methods: This study recruited consecutive patients from four hospitals between March 1, 2020, and July 31, 2021. Demographic characteristics, laboratory results, and clinical outcomes were determined. Results: Among the 239 enrolled patients, 11.2% (27/239) were infected with strain D614G and 88.7% (212/239) were infected with the Alpha variant. There were no significant differences in disease progression, rate of respiratory failure, subsequent development of acute respiratory distress syndrome (ARDS), acute kidney injury, cardiac injury, duration of stay in the intensive care unit or hospital, discharge rate, mortality rate, or viral RNA clearance time between the two groups. Multivariate Cox regression revealed that antibiotic therapy reduced the risk of delayed viral RNA clearance (hazard ratio [HR], 0.26; 95% confidence interval [CI], 0.13-0.55), while autoimmune disease increased the risk of delayed viral RNA clearance (HR, 3.98; 95% CI, 1.21-13.04). Elderly patients (age > 65 years) and patients with a history of cerebrovascular accident (CVA) were at increased risk of in-hospital mortality (HR, 5.14; 95% CI, 1.06-24.72 and HR, 3.62; 95% CI, 1.25-10.42, respectively). Conclusions: There were no significant differences between the D614G strain and Alpha variant of COVID-19 in terms of clinical characteristics and outcomes. However, factors affecting viral RNA clearance and the risk of in-hospital mortality were identified. These results could help to inform the future prioritization of resource allocation and identify patients in need of intense monitoring.

Superinfection of other hepatitis viruses on top of chronic hepatitis B: The more, the worse

Superinfection of other hepatitis viruses on top of chronic hepatitis B: The more, the worse

Comparison of SARS-CoV-2 RNA clearance between elderly and young patients with COVID-19

BackgroundThe SARS-CoV-2 outbreak in 2020 caused a highly transmissible disease with a significant impact on the elderly. Understanding viral clearance duration of COVID-19 is important to tailor prevention strategies to this vulnerable category. We aimed to investigate the SARS-CoV-2 infection duration and associated factors to prolonged viral clearance among elderly people comparatively to young people.MethodsWe conducted a cohort study of asymptomatic and mild forms of COVID-19 patients admitted to the designated national COVID-19 center in Monastir, Tunisia. Patients included in the study were divided into two cohorts: (elderly group: ≥ 60 years old) and (young group: < 60 years old) and were followed up to their RNA viral conversion. Stratified cox regression was performed to determine associated factors with prolonged viral SARS-CoV-2 RNA clearance in elderly subgroups.ResultsThe study included a total of 289 patients with asymptomatic and mild forms of COVID-19. The median term of viral shedding was 20 days (IQR; 16 - 32 days) for the young group, and 21 days (IQR; 17 - 33 days) for the elderly group. The stratified cox regression showed that Age ≥ 60 was an associated factor to prolonged viral shedding in male sex (HR (Hazard Ratio): 1.91; 95% CI: 1.19 - 3.07) and patients with comorbidities (HR:1.68; 95% CI: 1.02 - 2.75) especially diabetics (HR: 2.06; 95% CI: 1.01 - 4.21).ConclusionsThis study, focused on the factors associated with a prolonged duration of viral RNA clearance in elderly with COVID-19. These Potential factors will help planners to chalk out effective strategies among this vulnerable category.Key messages Old age is associated with a prolonged duration of viral RNA clearance in specific subgroups.Identifying these subgroups is important to know how prioritize preventive strategies in elderly.

Viral shedding in asymptomatic versus symptomatic patients with COVID-19

BackgroundAn outbreak of coronavirus disease 2019 (COVID-19) is becoming a public health emergency. Data are limited on the association between a prolonged viral shedding in patients with COVID-19 and having symptoms. We aimed to study the association between the presence of symptoms and recovery time of COVID-19 confirmed patients.MethodsWe conducted a prospective cohort study of COVID-19 patients admitted to the designated national COVID-19 center in Monastir, Tunisia from March to July 2020. Kaplan-Meier survival curve and Cox proportional hazards regression models were used to assess viral shedding in asymptomatic versus symptomatic patients with COVID-19.ResultsAmong the 264 patients included in the study, symptoms such as anosmia, dry cough, and fatigue were reported by 34.4% (n = 75) of cases. The median time to RNA viral conversion was 24 days (IQR 18-36 days) for symptomatic patients versus 20 days (IQR 16-30 days) for asymptomatic patients. Having symptoms was significantly associated with a prolonged viral shedding (HR 0.600, 95% CI 0.401-0.897) (p = 0.013).ConclusionsOur findings revealed that having symptoms delayed viral clearance among COVID-19 patients. Therefore, symptomatology should be taken into consideration in isolation strategy for infected patients.Key messages Having symptoms was associated with a delay in SARS-CoV-2 RNA clearance.The presence of symptoms should be taken into consideration for patient’s isolation strategy.

The association between face mask use and SARS-CoV-2 RNA viral clearance: A cohort study in Tunisia

BackgroundThe outbreak of coronavirus disease (COVID-19) continues to constitute an international public health concern. Scientific evidence showed that community mask wearing is an effective nonpharmacologic intervention to reduce the spread of this infection. However, few data are available about the effect of face masking on the duration of the disease. We aimed to study the association between recovery time among a Tunisian cohort of COVID-19 confirmed patients and mask wearing.MethodsA prospective cohort study was conducted from March to July 2020 including patients with COVID-19 admitted to the Tunisian national containment center. Data were collected via phone call interview. Kaplan-Meir Methods and Cox proportional hazards regression models were, respectively, used to study the association between recovery time and face masks use.ResultsAmong the 264 patients included, the median duration of viral clearance was 20 days (interquartile range (IQR 17-32days)). The median time to RNA viral conversion was 18 days (IQR 16-21 days) when using masks versus 23 days (IQR17-36 days) without wearing masks. Face masks use was significantly associated with an accelerated RNA clearance of SARS-CoV-2 (HR 2.006, 95% CI 1.247-3.228) (p = 0.004).ConclusionsWith the emergence of new variants, it is important to adopt widespread mask wearing to avoid SARS-CoV-2 infection and accelerate RNA negative conversion, until effective levels of vaccination are achieved nationally.Key messages Face masking was associated with accelerated RNA clearance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).Promoting community mask wearing during COVID-19 pandemic is crucial.

SARS-CoV-2 Blood RNA Load Predicts Outcome in Critically Ill COVID-19 Patients

BackgroundSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA loads in patient specimens may act as a clinical outcome predictor in critically ill patients with coronavirus disease 2019 (COVID-19).MethodsWe evaluated the predictive value of viral RNA loads and courses in the blood compared with the upper and lower respiratory tract loads of critically ill COVID-19 patients. Daily specimen collection and viral RNA quantification by reverse transcription quantitative polymerase chain reaction were performed in all consecutive 170 COVID-19 patients between March 2020 and February 2021 during the entire intensive care unit (ICU) stay (4145 samples analyzed). Patients were grouped according to their 90-day outcome as survivors (n=100) or nonsurvivors (n=70).ResultsIn nonsurvivors, blood SARS-CoV-2 RNA loads were significantly higher at the time of admission to the ICU (P=.0009). Failure of blood RNA clearance was observed in 33/50 (66%) of the nonsurvivors compared with 12/64 (19%) survivors (P<.0001). As determined by multivariate analysis, taking sociodemographic and clinical parameters into account, blood SARS-CoV-2 RNA load represents a valid and independent predictor of outcome in critically ill COVID-19 patients (odds ratio [OR; log10], 0.23; 95% CI, 0.12–0.42; P<.0001), with a significantly higher effect for survival compared with respiratory tract SARS-CoV-2 RNA loads (OR [log10], 0.75; 95% CI, 0.66–0.85; P<.0001). Blood RNA loads exceeding 2.51×103 SARS-CoV-2 RNA copies/mL were found to indicate a 50% probability of death. Consistently, 29/33 (88%) nonsurvivors with failure of virus clearance exceeded this cutoff value constantly.ConclusionsBlood SARS-CoV-2 load is an important independent outcome predictor and should be further evaluated for treatment allocation and patient monitoring.

Mechanism of action of favipiravir against SARS-CoV-2: Mutagenesis or chain termination?

Mechanism of action of favipiravir against SARS-CoV-2: Mutagenesis or chain termination?

Comparative therapeutic efficacy of interferon alfa-2b and combination lopinavir/ritonavir plus interferon alfa-2b against SARS-CoV-2

BackgroundThe outbreak of coronavirus disease 2019 (COVID-19) posed an enormous threat to public health. The use of antiviral drugs in patients with this disease have triggered people’s attentions. Whether interferon alfa-2b or lopinavir/ritonavir (LPV/r) plus interferon alfa-2b treatment can against SARS-CoV-2 was unknown. The objectives of this study was to evaluate the efficacy and safety of interferon alfa-2b and LPV/r plus interferon alfa-2b for SARS-CoV-2 infection in adult patients hospitalized with COVID-19.MethodsThis is a retrospective cohort study of 123 patients confirmed SARS-CoV-2 infection by PCR on nasopharyngeal swab and symptoms between Jan. 13 and Apr. 23, 2020. All patients received standard supportive care and regular clinical monitoring. Patients were assigned to standard care group (n = 12), interferon alfa-2b group (n = 44), and combination LPV/r plus interferon alfa-2b group (n = 67). The primary endpoints were duration of required oxygen support and virus clearance time. Associations between therapies and these outcomes were assessed by Cox proportional hazards regression.ResultsBaseline clinical characteristics were not significantly different among the three groups (P > 0.05). No significant associations were observed between LPV/r/interferon alfa-2b and faster SARS-CoV-2 RNA clearance (HR, 0.85 [95% confidence interval (CI) 0.45–1.61]; P = 0.61 in interferon alfa-2b group vs HR, 0.59 [95% CI 0.32–1.11]; P = 0.10 in LPV/r plus interferon alfa-2b group). Individual therapy groups also showed no significant association with duration of required oxygen support. There were no significant differences among the three groups in the incidence of adverse events (P > 0.05).ConclusionsIn patients with confirmed SARS-CoV-2 infection, no benefit was observed from interferon alfa-2b or LPV/r plus interferon alfa-2b treatment. The findings may provide references for treatment guidelines of patients with SARS-CoV-2 infection.

Large-Sized Graphene Oxide Nanosheets Increase DC-T-Cell Synaptic Contact and the Efficacy of DC Vaccines against SARS-CoV-2.

Dendritic cell (DC) vaccines are used for cancer and infectious diseases, albeit with limited efficacy. Modulating the formation of DC–T‐cell synapses may greatly increase their efficacy. The effects of graphene oxide (GO) nanosheets on DCs and DC–T‐cell synapse formation are evaluated. In particular, size‐dependent interactions are observed between GO nanosheets and DCs. GOs with diameters of >1 µm (L‐GOs) demonstrate strong adherence to the DC surface, inducing cytoskeletal reorganization via the RhoA‐ROCK‐MLC pathway, while relatively small GOs (≈500 nm) are predominantly internalized by DCs. Furthermore, L‐GO treatment enhances DC–T‐cell synapse formation via cytoskeleton‐dependent membrane positioning of integrin ICAM‐1. L‐GO acts as a “nanozipper,” facilitating the aggregation of DC–T‐cell clusters to produce a stable microenvironment for T cell activation. Importantly, L‐GO‐adjuvanted DCs promote robust cytotoxic T cell immune responses against SARS‐CoV‐2 spike 1, leading to >99.7% viral RNA clearance in mice infected with a clinically isolated SARS‐CoV‐2 strain. These findings highlight the potential value of nanomaterials as DC vaccine adjuvants for modulating DC–T‐cell synapse formation and provide a basis for the development of effective COVID‐19 vaccines.