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2.
Pathology ; 54(5): 623-628, 2022 Aug.
Article in English | MEDLINE | ID: covidwho-1907624

ABSTRACT

During the COVID-19 pandemic, the reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) assay has been the primary method of diagnosis of SARS-CoV-2 infection. However, RT-qPCR assay interpretation can be ambiguous with no universal absolute cut-off value to determine sample positivity, which particularly complicates the analysis of samples with high Ct values, or weak positives. Therefore, we sought to analyse factors associated with weak positive SARS-CoV-2 diagnosis. We analysed sample data associated with all positive SARS-CoV-2 RT-qPCR diagnostic tests performed by the Victorian Infectious Diseases Reference Laboratory (VIDRL) in Melbourne, Australia, during the Victorian first wave (22 January 2020-30 May 2020). A subset of samples was screened for the presence of host DNA and RNA using qPCR assays for CCR5 and 18S, respectively. Assays targeting the viral RNA-dependent RNA polymerase (RdRp) had higher Ct values than assays targeting the viral N and E genes. Weak positives were not associated with the age or sex of individuals' samples nor with reduced levels of host DNA and RNA. We observed a relationship between Ct value and time post-SARS-CoV-2 diagnosis. High Ct value or weak positive SARS-CoV-2 was not associated with any particular bias including poor biological sampling.


Subject(s)
COVID-19 , SARS-CoV-2 , COVID-19/diagnosis , COVID-19 Testing , Clinical Laboratory Techniques/methods , Humans , Pandemics , RNA, Viral/analysis , RNA, Viral/genetics , RNA-Directed DNA Polymerase/genetics , Real-Time Polymerase Chain Reaction/methods , Reverse Transcriptase Polymerase Chain Reaction , SARS-CoV-2/genetics , Sensitivity and Specificity
3.
J Int AIDS Soc ; 25(2): e25882, 2022 02.
Article in English | MEDLINE | ID: covidwho-1669512

ABSTRACT

INTRODUCTION: The International AIDS Society convened a multidisciplinary committee of experts in December 2020 to provide guidance and key considerations for the safe and ethical management of clinical trials involving people living with HIV (PLWH) during the SARS-CoV-2 pandemic. This consultation did not discuss guidance for the design of prevention studies for people at risk of HIV acquisition, nor for the programmatic delivery of antiretroviral therapy (ART). DISCUSSION: There is strong ambition to continue with HIV research from both PLWH and the research community despite the ongoing SARS-CoV-2 pandemic. How to do this safely and justly remains a critical debate. The SARS-CoV-2 pandemic continues to be highly dynamic. It is expected that with the emergence of effective SARS-CoV-2 prevention and treatment strategies, the risk to PLWH in clinical trials will decline over time. However, with the emergence of more contagious and potentially pathogenic SARS-CoV-2 variants, the effectiveness of current prevention and treatment strategies may be compromised. Uncertainty exists about how equally SARS-CoV-2 prevention and treatment strategies will be available globally, particularly for marginalized populations, many of whom are at high risk of reduced access to ART and/or HIV disease progression. All of these factors must be taken into account when deciding on the feasibility and safety of developing and implementing HIV research. CONCLUSIONS: It can be assumed for the foreseeable future that SARS-CoV-2 will persist and continue to pose challenges to conducting clinical research in PLWH. Guidelines regarding how best to implement HIV treatment studies will evolve accordingly. The risks and benefits of performing an HIV clinical trial must be carefully evaluated in the local context on an ongoing basis. With this document, we hope to provide a broad guidance that should remain viable and relevant even as the nature of the pandemic continues to develop.


Subject(s)
COVID-19 , HIV Infections , HIV Infections/drug therapy , HIV Infections/epidemiology , HIV Infections/prevention & control , Humans , Pandemics , SARS-CoV-2
4.
Open Forum Infect Dis ; 8(7): ofab239, 2021 Jul.
Article in English | MEDLINE | ID: covidwho-1309620

ABSTRACT

BACKGROUND: Serological testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) complements nucleic acid tests for patient diagnosis and enables monitoring of population susceptibility to inform the coronavirus disease 2019 (COVID-19) pandemic response. It is important to understand the reliability of assays with different antigen or antibody targets to detect humoral immunity after SARS-CoV-2 infection and to understand how antibody (Ab) binding assays compare to those detecting neutralizing antibody (nAb), particularly as we move into the era of vaccines. METHODS: We evaluated the performance of 6 commercially available enzyme-linked immunosorbent assays (ELISAs), including a surrogate virus neutralization test (sVNT), for detection of SARS-CoV-2 immunoglobulins (IgA, IgM, IgG), total or nAb. A result subset was compared with a cell culture-based microneutralization (MN) assay. We tested sera from patients with prior reverse transcription polymerase chain reaction-confirmed SARS-CoV-2 infection, prepandemic sera, and potential cross-reactive sera from patients with other non-COVID-19 acute infections. RESULTS: For sera collected >14 days post-symptom onset, the assay achieving the highest sensitivity was the Wantai total Ab at 100% (95% CI, 94.6%-100%), followed by 93.1% for Euroimmun NCP-IgG, 93.1% for GenScript sVNT, 90.3% for Euroimmun S1-IgG, 88.9% for Euroimmun S1-IgA, and 83.3% for Wantai IgM. Specificity for the best-performing assay was 99.5% for the Wantai total Ab, and for the lowest-performing assay it was 97.1% for sVNT (as per the Instructions for Use [IFU]). The Wantai Total Ab had the best agreement with MN at 98% followed by Euroimmun S1-IgA, Euro NCP-IgG, and sVNT (as per IFU) with 97%, 97% and 95%, respectively; Wantai IgM had the poorest agreement at 93%. CONCLUSIONS: Performance characteristics of the SARS-CoV-2 serology assays detecting different antibody types are consistent with those found in previously published reports. Evaluation of the surrogate virus neutralization test in comparison to the Ab binding assays and a cell culture-based neutralization assay showed good result correlation between all assays. However, correlation between the cell-based neutralization test and some assays detecting Ab's not specifically involved in neutralization was higher than with the sVNT. This study demonstrates the reliability of different assays to detect the humoral immune response following SARS-CoV-2 infection, which can be used to optimize serological test algorithms for assessing antibody responses post-SARS-CoV-2 infection or vaccination.

5.
Nat Commun ; 12(1): 4270, 2021 07 13.
Article in English | MEDLINE | ID: covidwho-1309444

ABSTRACT

The recent dramatic appearance of variants of concern of SARS-coronavirus-2 (SARS-CoV-2) highlights the need for innovative approaches that simultaneously suppress viral replication and circumvent viral escape from host immunity and antiviral therapeutics. Here, we employ genome-wide computational prediction and single-nucleotide resolution screening to reprogram CRISPR-Cas13b against SARS-CoV-2 genomic and subgenomic RNAs. Reprogrammed Cas13b effectors targeting accessible regions of Spike and Nucleocapsid transcripts achieved >98% silencing efficiency in virus-free models. Further, optimized and multiplexed Cas13b CRISPR RNAs (crRNAs) suppress viral replication in mammalian cells infected with replication-competent SARS-CoV-2, including the recently emerging dominant variant of concern B.1.1.7. The comprehensive mutagenesis of guide-target interaction demonstrated that single-nucleotide mismatches does not impair the capacity of a potent single crRNA to simultaneously suppress ancestral and mutated SARS-CoV-2 strains in infected mammalian cells, including the Spike D614G mutant. The specificity, efficiency and rapid deployment properties of reprogrammed Cas13b described here provide a molecular blueprint for antiviral drug development to suppress and prevent a wide range of SARS-CoV-2 mutants, and is readily adaptable to other emerging pathogenic viruses.


Subject(s)
Mutation , SARS-CoV-2/physiology , Virus Replication/physiology , Animals , Antiviral Agents/pharmacology , COVID-19/drug therapy , COVID-19/virology , CRISPR-Cas Systems , Chlorocebus aethiops , Clustered Regularly Interspaced Short Palindromic Repeats , Drug Development , Genome, Viral , HEK293 Cells , Humans , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/metabolism , Vero Cells , Virus Replication/genetics
6.
Lancet Reg Health West Pac ; 9: 100115, 2021 Apr.
Article in English | MEDLINE | ID: covidwho-1117260

ABSTRACT

BACKGROUND: In Australia, COVID-19 diagnosis relies on RT-PCR testing which is relatively costly and time-consuming. To date, few studies have assessed the performance and implementation of rapid antigen-based SARS-CoV-2 testing in a setting with a low prevalence of COVID-19 infections, such as Australia. METHODS: This study recruited participants presenting for COVID-19 testing at three Melbourne metropolitan hospitals during a period of low COVID-19 prevalence. The Abbott PanBioTM COVID-19 Ag point-of-care test was performed alongside RT-PCR. In addition, participants with COVID-19 notified to the Victorian Government were invited to provide additional swabs to aid validation. Implementation challenges were also documented. FINDINGS: The specificity of the Abbott PanBioTM COVID-19 Ag test was 99.96% (95% CI 99.73 - 100%). Sensitivity amongst participants with RT-PCR-confirmed infection was dependent upon the duration of symptoms reported, ranging from 77.3% (duration 1 to 33 days) to 100% in those within seven days of symptom onset. A range of implementation challenges were identified which may inform future COVID-19 testing strategies in a low prevalence setting. INTERPRETATION: Given the high specificity, antigen-based tests may be most useful in rapidly triaging public health and hospital resources while expediting confirmatory RT-PCR testing. Considering the limitations in test sensitivity and the potential for rapid transmission in susceptible populations, particularly in hospital settings, careful consideration is required for implementation of antigen testing in a low prevalence setting. FUNDING: This work was funded by the Victorian Department of Health and Human Services. The funder was not involved in data analysis or manuscript preparation.

7.
Cell Rep Med ; 2(3): 100208, 2021 03 16.
Article in English | MEDLINE | ID: covidwho-1065663

ABSTRACT

SARS-CoV-2 causes a spectrum of COVID-19 disease, the immunological basis of which remains ill defined. We analyzed 85 SARS-CoV-2-infected individuals at acute and/or convalescent time points, up to 102 days after symptom onset, quantifying 184 immunological parameters. Acute COVID-19 presented with high levels of IL-6, IL-18, and IL-10 and broad activation marked by the upregulation of CD38 on innate and adaptive lymphocytes and myeloid cells. Importantly, activated CXCR3+cTFH1 cells in acute COVID-19 significantly correlate with and predict antibody levels and their avidity at convalescence as well as acute neutralization activity. Strikingly, intensive care unit (ICU) patients with severe COVID-19 display higher levels of soluble IL-6, IL-6R, and IL-18, and hyperactivation of innate, adaptive, and myeloid compartments than patients with moderate disease. Our analyses provide a comprehensive map of longitudinal immunological responses in COVID-19 patients and integrate key cellular pathways of complex immune networks underpinning severe COVID-19, providing important insights into potential biomarkers and immunotherapies.


Subject(s)
Antibody Formation , COVID-19/immunology , Adaptive Immunity , Adult , Aged , Antibodies, Viral/blood , B-Lymphocytes/cytology , B-Lymphocytes/metabolism , COVID-19/pathology , COVID-19/virology , Female , Humans , Immunity, Innate , Interleukin-18/metabolism , Interleukin-6/metabolism , Male , Middle Aged , Receptors, CXCR3/metabolism , Receptors, Interleukin-6/metabolism , SARS-CoV-2/immunology , SARS-CoV-2/isolation & purification , Severity of Illness Index , Th1 Cells/cytology , Th1 Cells/metabolism , Young Adult
12.
J Infect Dis ; 222(8): 1280-1288, 2020 09 14.
Article in English | MEDLINE | ID: covidwho-695351

ABSTRACT

BACKGROUND: Robust serological assays are essential for long-term control of the COVID-19 pandemic. Many recently released point-of-care (PoCT) serological assays have been distributed with little premarket validation. METHODS: Performance characteristics for 5 PoCT lateral flow devices approved for use in Australia were compared to a commercial enzyme immunoassay (ELISA) and a recently described novel surrogate virus neutralization test (sVNT). RESULTS: Sensitivities for PoCT ranged from 51.8% (95% confidence interval [CI], 43.1%-60.4%) to 67.9% (95% CI, 59.4%-75.6%), and specificities from 95.6% (95% CI, 89.2%-98.8%) to 100.0% (95% CI, 96.1%-100.0%). ELISA sensitivity for IgA or IgG detection was 67.9% (95% CI, 59.4%-75.6%), increasing to 93.8% (95% CI, 85.0%-98.3%) for samples >14 days post symptom onset. sVNT sensitivity was 60.9% (95% CI, 53.2%-68.4%), rising to 91.2% (95% CI, 81.8%-96.7%) for samples >14 days post symptom onset, with specificity 94.4% (95% CI, 89.2%-97.5%). CONCLUSIONS: Performance characteristics for COVID-19 serological assays were generally lower than those reported by manufacturers. Timing of specimen collection relative to onset of illness or infection is crucial in reporting of performance characteristics for COVID-19 serological assays. The optimal algorithm for implementing serological testing for COVID-19 remains to be determined, particularly in low-prevalence settings.


Subject(s)
Coronavirus Infections/blood , Pneumonia, Viral/blood , Algorithms , Antibodies, Viral/blood , Australia/epidemiology , Betacoronavirus/isolation & purification , COVID-19 , COVID-19 Testing , Clinical Laboratory Techniques , Coronavirus Infections/diagnosis , Coronavirus Infections/epidemiology , Enzyme-Linked Immunosorbent Assay , Humans , Immunoglobulin A/blood , Immunoglobulin G/blood , Neutralization Tests/methods , Pandemics , Pneumonia, Viral/diagnosis , Pneumonia, Viral/epidemiology , Prevalence , Reverse Transcriptase Polymerase Chain Reaction/methods , SARS-CoV-2 , Serologic Tests/methods , Serologic Tests/standards
14.
Med J Aust ; 212(10): 459-462, 2020 06.
Article in English | MEDLINE | ID: covidwho-39583

ABSTRACT

OBJECTIVES: To describe the first isolation and sequencing of SARS-CoV-2 in Australia and rapid sharing of the isolate. SETTING: SARS-CoV-2 was isolated from a 58-year-old man from Wuhan, China who arrived in Melbourne on 19 January 2020 and was admitted to the Monash Medical Centre, Melbourne from the emergency department on 24 January 2020 with fever, cough, and progressive dyspnoea. MAJOR OUTCOMES: Clinical course and laboratory features of the first reported case of COVID-19 (the illness caused by SARS-CoV-2) in Australia; isolation, whole genome sequencing, imaging, and rapid sharing of virus from the patient. RESULTS: A nasopharyngeal swab and sputum collected when the patient presented to hospital were each positive for SARS-CoV-2 (reverse transcription polymerase chain reaction). Inoculation of Vero/hSLAM cells with material from the nasopharyngeal swab led to the isolation of SARS-CoV-2 virus in culture. Electron microscopy of the supernatant confirmed the presence of virus particles with morphology characteristic of viruses of the family Coronaviridae. Whole genome sequencing of the viral isolate and phylogenetic analysis indicated the isolate exhibited greater than 99.99% sequence identity with other publicly available SARS-CoV-2 genomes. Within 24 hours of isolation, the first Australian SARS-CoV-2 isolate was shared with local and overseas reference laboratories and major North American and European culture collections. CONCLUSIONS: The ability to rapidly identify, propagate, and internationally share our SARS-CoV-2 isolate is an important step in collaborative scientific efforts to deal effectively with this international public health emergency by developing better diagnostic procedures, vaccine candidates, and antiviral agents.


Subject(s)
Betacoronavirus/genetics , Coronavirus Infections/genetics , Information Dissemination/methods , Patient Isolation/methods , Pneumonia, Viral/genetics , Australia , COVID-19 , Coronavirus Infections/diagnosis , Humans , Male , Middle Aged , Pandemics , Pneumonia, Viral/diagnosis , SARS-CoV-2 , Whole Genome Sequencing
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