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1.
EuropePMC; 2022.
Preprint in English | EuropePMC | ID: ppcovidwho-332043

ABSTRACT

Especially during global pandemics but also in the context of epidemic waves, the capacity for diagnostic qRT-PCRs rapidly becomes a limiting factor. Furthermore, excessive testing incurs high costs and can result in an overstrained work force in diagnostics departments. Obviously, people aim to shorten their isolation periods, hospitals need to discharge convalescent people, and re-employ staff members after infection. The aim of the study was to optimize retesting regimens for test-to-release from isolation and return-to-work applications. For this purpose, we investigated the association between Ct values at the first diagnosis of SARS-CoV-2 infection and the period until test negativity was reached, or at least until the Ct value exceeded 30, which is considered to indicate the transition to a non-infectious state. We included results from the testing of respiratory material samples for the detection of SARS-CoV-2 RNA, tested from 01 March 2020 to 31 January 2022. Lower initial Ct values were associated with longer periods of SARS-CoV-2 RNA positivity. Starting with Ct values of <20, 20-25, 25-30, 30-35, and >35, it took median intervals of 20 (interval: 14-25), 16 (interval: 10-21), 12 (interval: 7-16), 7 (interval: 5-14), and 5 (interval: 2-7) days, respectively, until the person tested negative. Accordingly, a Ct threshold of 30 was surpassed after 13 (interval: 8-19), 9 (interval: 6-14), 7 (interval: 6-11), 6 (interval: 4-10), and 3 (interval: 1-6) days, respectively, in individuals with aforementioned start Ct values. Furthermore, the time to negativity was longer for adults versus children, wild-type SARS-CoV-2 variant versus other variants of concern, and in patients who were treated in the intensive care units. Based on these data, we propose an adjusted retesting strategy according to the initial Ct value in order to optimize available PCR resources.

2.
J Med Virol ; 2021 Oct 11.
Article in English | MEDLINE | ID: covidwho-1718355

ABSTRACT

During the first wave of the pandemic, we compared the occurrence of subjectively experienced COVID-19-like symptoms and true severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seroconversion rates among medical personnel in general practices. This cross-sectional study determined the SARS-CoV-2-specific immunoglobulin G (IgG) antibody status of medical staff from 100 outpatient practices in Germany. Study cohort characteristics and COVID-19-like symptoms were obtained by questionnaires. The initial screening for SARS-CoV-2-recognizing antibodies was performed using a commercial chemiluminescence microparticle immunoassay. Positive results were controlled with another approved test. Samples with discrepant results were subjected to a third IgG-binding assay and a neutralization test. A total of 861 participants were included, 1.7% (n = 15) of whom tested positive for SARS-CoV-specific IgG in the initial screening test. In 46.6% (n = 7) of positive cases, test results were confirmed by an independent test. In the eight samples with discrepant results, neither spike-specific antibodies nor in vitro neutralizing capacity were detectable, resulting in a genuine seroprevalence rate of 0.8%. 794 participants completed the questionnaire. Intriguingly, a total of 53.7% (n = 426) of them stated episodes of COVID-19-like symptoms. Except for smell and taste dysfunction, there were no significant differences between the groups with and without laboratory-confirmed SARS-CoV-2 seroconversion. Our results demonstrated that only 0.8% of participants acquired SARS-CoV-2 even though 53.7% of participants reportedly experienced COVID-19-like symptoms. Thus, even among medical staff, self-diagnosis based on subjectively experienced symptoms does not have a relevant predictive value.

3.
Proc Natl Acad Sci U S A ; 119(8)2022 02 22.
Article in English | MEDLINE | ID: covidwho-1671749

ABSTRACT

Type I interferons (IFN-I) exert pleiotropic biological effects during viral infections, balancing virus control versus immune-mediated pathologies, and have been successfully employed for the treatment of viral diseases. Humans express 12 IFN-alpha (α) subtypes, which activate downstream signaling cascades and result in distinct patterns of immune responses and differential antiviral responses. Inborn errors in IFN-I immunity and the presence of anti-IFN autoantibodies account for very severe courses of COVID-19; therefore, early administration of IFN-I may be protective against life-threatening disease. Here we comprehensively analyzed the antiviral activity of all IFNα subtypes against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to identify the underlying immune signatures and explore their therapeutic potential. Prophylaxis of primary human airway epithelial cells (hAEC) with different IFNα subtypes during SARS-CoV-2 infection uncovered distinct functional classes with high, intermediate, and low antiviral IFNs. In particular, IFNα5 showed superior antiviral activity against SARS-CoV-2 infection in vitro and in SARS-CoV-2-infected mice in vivo. Dose dependency studies further displayed additive effects upon coadministration with the broad antiviral drug remdesivir in cell culture. Transcriptomic analysis of IFN-treated hAEC revealed different transcriptional signatures, uncovering distinct, intersecting, and prototypical genes of individual IFNα subtypes. Global proteomic analyses systematically assessed the abundance of specific antiviral key effector molecules which are involved in IFN-I signaling pathways, negative regulation of viral processes, and immune effector processes for the potent antiviral IFNα5. Taken together, our data provide a systemic, multimodular definition of antiviral host responses mediated by defined IFN-I. This knowledge will support the development of novel therapeutic approaches against SARS-CoV-2.


Subject(s)
COVID-19/drug therapy , Interferon-alpha/pharmacology , SARS-CoV-2/drug effects , Transcriptome , Virus Replication/drug effects , Animals , COVID-19/immunology , COVID-19/virology , Chlorocebus aethiops , Cloning, Molecular , Disease Models, Animal , Escherichia coli/genetics , Escherichia coli/metabolism , Gene Expression Profiling , Gene Expression Regulation , Genetic Vectors/chemistry , Genetic Vectors/metabolism , Humans , Interferon-alpha/genetics , Interferon-alpha/immunology , Mice , Protein Isoforms/classification , Protein Isoforms/genetics , Protein Isoforms/immunology , Protein Isoforms/pharmacology , Recombinant Proteins/classification , Recombinant Proteins/genetics , Recombinant Proteins/immunology , Recombinant Proteins/pharmacology , SARS-CoV-2/genetics , SARS-CoV-2/immunology , Signal Transduction , Vero Cells
4.
Emerg Microbes Infect ; 11(1): 483-497, 2022 Dec.
Article in English | MEDLINE | ID: covidwho-1606402

ABSTRACT

Coronavirus disease 2019 (COVID-19) caused by the emerging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has set off a global pandemic. There is an urgent unmet need for safe, affordable, and effective therapeutics against COVID-19. In this regard, drug repurposing is considered as a promising approach. We assessed the compounds that affect the endosomal acidic environment by applying human angiotensin-converting enzyme 2 (hACE2)- expressing cells infected with a SARS-CoV-2 spike (S) protein-pseudotyped HIV reporter virus and identified that obatoclax resulted in the strongest inhibition of S protein-mediated virus entry. The potent antiviral activity of obatoclax at nanomolar concentrations was confirmed in different human lung and intestinal cells infected with the SARS-CoV-2 pseudotype system as well as clinical virus isolates. Furthermore, we uncovered that obatoclax executes a double-strike against SARS-CoV-2. It prevented SARS-CoV-2 entry by blocking endocytosis of virions through diminished endosomal acidification and the corresponding inhibition of the enzymatic activity of the endosomal cysteine protease cathepsin L. Additionally, obatoclax impaired the SARS-CoV-2 S-mediated membrane fusion by targeting the MCL-1 protein and reducing furin protease activity. In accordance with these overarching mechanisms, obatoclax blocked the virus entry mediated by different S proteins derived from several SARS-CoV-2 variants of concern such as, Alpha (B.1.1.7), Beta (B.1.351), and Delta (B.1.617.2). Taken together, our results identified obatoclax as a novel effective antiviral compound that keeps SARS-CoV-2 at bay by blocking both endocytosis and membrane fusion. Our data suggested that obatoclax should be further explored as a clinical drug for the treatment of COVID-19.


Subject(s)
Cathepsins/metabolism , Furin/metabolism , Indoles/pharmacology , Pyrroles/pharmacology , SARS-CoV-2 , Virus Internalization/drug effects , COVID-19 , Humans , Hydrogen-Ion Concentration , SARS-CoV-2/drug effects , Spike Glycoprotein, Coronavirus
5.
iScience ; 24(10): 103194, 2021 Oct 22.
Article in English | MEDLINE | ID: covidwho-1446743

ABSTRACT

The COVID-19 pandemic poses enormous challenges to global healthcare sectors. To prevent the overburden of medical systems, it is crucial to distinguish individuals approaching the most infectious early phase from those in the declining non-infectious phase. However, a large fraction of transmission events occur during pre- or asymptomatic phases. Especially in the absence of symptoms, it is difficult to distinguish prodromal from late phases of infection just by RT-PCR since both phases are characterized by low viral loads and corresponding high Ct values (>30). We evaluated a new rapid test detecting IgG antibodies recognizing SARS-CoV-2 nucleocapsid protein using two commercial antibody assays and an in-house neutralization test before determining suitability for testing clinical swab material. Our analyses revealed the combination of the well-known RT-PCR and the new rapid antibody test using one single clinical nasopharyngeal swab specimen as a fast, cost-effective, and reliable way to discriminate prodromal from subsiding phases of COVID-19.

6.
Viruses ; 13(10)2021 09 23.
Article in English | MEDLINE | ID: covidwho-1438743

ABSTRACT

Severe Acute Respiratory Syndrome Coronavirus Type 2 (SARS-CoV-2) is the causative agent of the coronavirus disease 2019 (COVID-19). The availability of effective and well-tolerated antiviral drugs for the treatment of COVID-19 patients is still very limited. Traditional herbal medicines elicit antiviral activity against various viruses and might therefore represent a promising option for the complementary treatment of COVID-19 patients. The application of turmeric root in herbal medicine has a very long history. Its bioactive ingredient curcumin shows a broad-spectrum antimicrobial activity. In the present study, we investigated the antiviral activity of aqueous turmeric root extract, the dissolved content of a curcumin-containing nutritional supplement capsule, and pure curcumin against SARS-CoV-2. Turmeric root extract, dissolved turmeric capsule content, and pure curcumin effectively neutralized SARS-CoV-2 at subtoxic concentrations in Vero E6 and human Calu-3 cells. Furthermore, curcumin treatment significantly reduced SARS-CoV-2 RNA levels in cell culture supernatants. Our data uncover curcumin as a promising compound for complementary COVID-19 treatment. Curcumin concentrations contained in turmeric root or capsules used as nutritional supplements completely neutralized SARS-CoV-2 in vitro. Our data argue in favor of appropriate and carefully monitored clinical studies that vigorously test the effectiveness of complementary treatment of COVID-19 patients with curcumin-containing products.


Subject(s)
COVID-19/drug therapy , Curcumin/therapeutic use , SARS-CoV-2/drug effects , Animals , Antiviral Agents/therapeutic use , Cell Line , Chlorocebus aethiops , Curcuma/metabolism , Curcumin/metabolism , Dietary Supplements , Humans , Medicine, Traditional/methods , Plant Extracts/metabolism , Plant Extracts/therapeutic use , SARS-CoV-2/metabolism , SARS-CoV-2/pathogenicity , Vero Cells
7.
Front Immunol ; 12: 722027, 2021.
Article in English | MEDLINE | ID: covidwho-1399138

ABSTRACT

Approximately half of the SARS-CoV-2 infections occur without apparent symptoms, raising questions regarding long-term humoral immunity in asymptomatic individuals. Plasma levels of immunoglobulin G (IgG) and M (IgM) against the viral spike or nucleoprotein were determined for 25,091 individuals enrolled in a surveillance program in Wuhan, China. We compared 405 asymptomatic individuals who mounted a detectable antibody response with 459 symptomatic COVID-19 patients. The well-defined duration of the SARS-CoV-2 endemic in Wuhan allowed a side-by-side comparison of antibody responses following symptomatic and asymptomatic infections without subsequent antigen re-exposure. IgM responses rapidly declined in both groups. However, both the prevalence and durability of IgG responses and neutralizing capacities correlated positively with symptoms. Regardless of sex, age, and body weight, asymptomatic individuals lost their SARS-CoV-2-specific IgG antibodies more often and rapidly than symptomatic patients did. These findings have important implications for immunity and favour immunization programs including individuals after asymptomatic infections.


Subject(s)
Antibodies, Viral/blood , Asymptomatic Infections/epidemiology , COVID-19/immunology , Immunity, Humoral , SARS-CoV-2/immunology , Adult , Antibodies, Neutralizing/immunology , Antibody Formation , COVID-19/epidemiology , China , Epidemiological Monitoring , Female , Humans , Immunoglobulin G/immunology , Immunoglobulin M/immunology , Male , Middle Aged , Retrospective Studies , SARS-CoV-2/pathogenicity , Young Adult
8.
J Med Virol ; 93(5): 2848-2856, 2021 05.
Article in English | MEDLINE | ID: covidwho-954063

ABSTRACT

During the coronavirus disease 2019 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), reliable diagnostics are absolutely indispensable. Molecular SARS-CoV-2 diagnostics based on nucleic acids (NA) derived from oro- or nasopharyngeal swabs constitute the current gold standard. Given the importance of test results, it is crucial to assess the quality of the underlying swab samples and NA extraction procedures. We determined NA concentrations in clinical samples used for SARS-CoV-2 testing applying an NA-specific dye. In comparison to cut-offs defined by SARS-CoV-2-positive samples, internal positive controls, and references from a federal laboratory, 90.85% (923 of 1016) of swabs contained NA concentrations enabling SARS-CoV-2 recognition. Swabs collected by local health authorities and the central emergency department either had significantly higher NA concentrations or were less likely to exhibit insufficient quality, arguing in favor of sampling centers with routined personnel. Interestingly, samples taken from females had significantly higher NA concentrations than those from males. Among eight longitudinal patient sample sets with intermitting negative quantitative reverse transcription polymerase chain reaction results, two showed reduced NA concentrations in negative specimens. The herein described fluorescence-based NA quantification approach is immediately applicable to evaluate swab qualities, optimize sampling strategies, identify patient-specific differences, and explain some peculiar test results including intermittent negative samples with low NA concentrations.


Subject(s)
COVID-19 Nucleic Acid Testing/methods , COVID-19/diagnosis , Molecular Diagnostic Techniques/methods , SARS-CoV-2/isolation & purification , Specimen Handling/methods , Adolescent , Adult , Aged , Aged, 80 and over , COVID-19 Testing/methods , Child , Child, Preschool , Clinical Laboratory Techniques/methods , Coronavirus Envelope Proteins/genetics , Diagnostic Tests, Routine , Female , Humans , Infant , Infant, Newborn , Male , Middle Aged , Nasopharynx/virology , Quality Control , RNA, Viral/analysis , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus , Young Adult
9.
Front Immunol ; 11: 573526, 2020.
Article in English | MEDLINE | ID: covidwho-902401

ABSTRACT

The coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is currently the most pressing medical and socioeconomic challenge. Constituting important correlates of protection, the determination of virus-neutralizing antibodies (NAbs) is indispensable for convalescent plasma selection, vaccine candidate evaluation, and immunity certificates. In contrast to standard serological ELISAs, plaque reduction neutralization tests (PRNTs) are laborious, time-consuming, expensive, and restricted to specialized laboratories. To replace microscopic counting-based SARS-CoV-2 PRNTs by a novel assay exempt from genetically modified viruses, which are inapplicable in most diagnostics departments, we established a simple, rapid, and automated SARS-CoV-2 neutralization assay employing an in-cell ELISA (icELISA) approach. After optimization of various parameters such as virus-specific antibodies, cell lines, virus doses, and duration of infection, SARS-CoV-2-infected cells became amenable as direct antigen source for quantitative icELISA. Antiviral agents such as human sera containing NAbs or antiviral interferons dose dependently reduced the SARS-CoV-2-specific signal. Applying increased infectious doses, the icELISA-based neutralization test (icNT) was superior to PRNT in discriminating convalescent sera with high from those with intermediate neutralizing capacities. In addition, the icNT was found to be specific, discriminating between SARS-CoV-2-specific NAbs and those raised against other coronaviruses. Altogether, the SARS-CoV-2 icELISA test allows rapid (<48 h in total, read-out in seconds) and automated quantification of virus infection in cell culture to evaluate the efficacy of NAbs and antiviral drugs using reagents and equipment present in most routine diagnostics departments.


Subject(s)
Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19 Testing/methods , COVID-19/diagnosis , SARS-CoV-2/immunology , Animals , Antibodies, Neutralizing/blood , Antibodies, Neutralizing/therapeutic use , Antibodies, Viral/blood , Antibodies, Viral/therapeutic use , Antiviral Agents/pharmacology , COVID-19/therapy , COVID-19/virology , Caco-2 Cells , Chlorocebus aethiops , Diagnostic Tests, Routine/methods , Enzyme-Linked Immunosorbent Assay/methods , Humans , Immunization, Passive , Neutralization Tests/methods , SARS-CoV-2/genetics , Vero Cells , Virus Replication/drug effects , Virus Replication/immunology
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