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1.
J Med Virol ; 92(10): 2227-2231, 2020 10.
Article in English | MEDLINE | ID: covidwho-935128

ABSTRACT

Patients with coronavirus disease-2019 may be discharged based on clinical resolution of symptoms, and evidence for viral RNA clearance from the upper respiratory tract. Understanding the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral clearance profile is crucial to establish a re-testing plan on discharge and ending isolation of patients. We aimed to evaluate the number of days that a patient needed to achieve undetectable levels of SARS-CoV-2 in upper respiratory tract specimens (nasopharyngeal swab and/or an oropharyngeal swab). The clearance and persistence of viral RNA was evaluated in two groups of positive patients: those who achieved two negative reverse transcription-polymerase chain reaction (RT-PCR) tests and those who kept testing positive. Patients were organized thereafter in two subgroups, mild illness patients discharged home and inpatients who had moderate to severe illness. Results from RT-PCR tests were then correlated with results from the evaluation of the immune response. The study evidenced that most patients tested positive for more than 2 weeks and that persistence of viral RNA is not necessarily associated with severe disease but may result from a weaker immune response instead.


Subject(s)
COVID-19/diagnosis , Patient Discharge/statistics & numerical data , RNA, Viral/genetics , SARS-CoV-2/genetics , Adult , Aged , Aged, 80 and over , COVID-19/immunology , COVID-19/pathology , COVID-19/virology , COVID-19 Testing/methods , Child , Convalescence , Cross-Sectional Studies , Female , Humans , Male , Middle Aged , Nasopharynx/virology , Oropharynx/virology , Retrospective Studies , Reverse Transcriptase Polymerase Chain Reaction , SARS-CoV-2/immunology , SARS-CoV-2/pathogenicity , Severity of Illness Index
2.
Disaster Med Public Health Prep ; : 1-2, 2020 Nov 19.
Article in English | MEDLINE | ID: covidwho-933592

ABSTRACT

The relation of continuing to test positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by reverse transcription real-time polymerase chain reaction (RT-PCR) to infectivity remains unclear, with numerous consequences. This report describes 2 patients with persistent viral detection by RT-PCR for 77 and 72 days, respectively, longer than other reported case-patients who were otherwise healthy.

3.
J Clin Med ; 9(10)2020 Oct 01.
Article in English | MEDLINE | ID: covidwho-905123

ABSTRACT

Although antibody response to SARS-CoV-2 can be detected early during the infection, several outstanding questions remain to be addressed regarding the magnitude and persistence of antibody titer against different viral proteins and their correlation with the strength of the immune response. An ELISA assay has been developed by expressing and purifying the recombinant SARS-CoV-2 Spike Receptor Binding Domain (RBD), Soluble Ectodomain (Spike), and full length Nucleocapsid protein (N). Sera from healthcare workers affected by non-severe COVID-19 were longitudinally collected over four weeks, and compared to sera from patients hospitalized in Intensive Care Units (ICU) and SARS-CoV-2-negative subjects for the presence of IgM, IgG and IgA antibodies as well as soluble pro-inflammatory mediators in the sera. Non-hospitalized subjects showed lower antibody titers and blood pro-inflammatory cytokine profiles as compared to patients in Intensive Care Units (ICU), irrespective of the antibodies tested. Noteworthy, in non-severe COVID-19 infections, antibody titers against RBD and Spike, but not against the N protein, as well as pro-inflammatory cytokines decreased within a month after viral clearance. Thus, rapid decline in antibody titers and in pro-inflammatory cytokines may be a common feature of non-severe SARS-CoV-2 infection, suggesting that antibody-mediated protection against re-infection with SARS-CoV-2 is of short duration. These results suggest caution in using serological testing to estimate the prevalence of SARS-CoV-2 infection in the general population.

4.
Sci Immunol ; 5(52)2020 10 08.
Article in English | MEDLINE | ID: covidwho-842518

ABSTRACT

We measured plasma and/or serum antibody responses to the receptor-binding domain (RBD) of the spike (S) protein of SARS-CoV-2 in 343 North American patients infected with SARS-CoV-2 (of which 93% required hospitalization) up to 122 days after symptom onset and compared them to responses in 1548 individuals whose blood samples were obtained prior to the pandemic. After setting seropositivity thresholds for perfect specificity (100%), we estimated sensitivities of 95% for IgG, 90% for IgA, and 81% for IgM for detecting infected individuals between 15 and 28 days after symptom onset. While the median time to seroconversion was nearly 12 days across all three isotypes tested, IgA and IgM antibodies against RBD were short-lived with median times to seroreversion of 71 and 49 days after symptom onset. In contrast, anti-RBD IgG responses decayed slowly through 90 days with only 3 seropositive individuals seroreverting within this time period. IgG antibodies to SARS-CoV-2 RBD were strongly correlated with anti-S neutralizing antibody titers, which demonstrated little to no decrease over 75 days since symptom onset. We observed no cross-reactivity of the SARS-CoV-2 RBD-targeted antibodies with other widely circulating coronaviruses (HKU1, 229 E, OC43, NL63). These data suggest that RBD-targeted antibodies are excellent markers of previous and recent infection, that differential isotype measurements can help distinguish between recent and older infections, and that IgG responses persist over the first few months after infection and are highly correlated with neutralizing antibodies.


Subject(s)
Antibodies, Viral/immunology , Betacoronavirus/immunology , Coronavirus Infections/epidemiology , Pneumonia, Viral/epidemiology , Protein Domains/immunology , Spike Glycoprotein, Coronavirus/immunology , Adult , Aged , Antibodies, Neutralizing/immunology , Antibodies, Viral/blood , Betacoronavirus/genetics , Biomarkers/blood , COVID-19 , Cohort Studies , Coronavirus Infections/virology , Cross Reactions , Dried Blood Spot Testing , Female , Humans , Immunoglobulin A/blood , Immunoglobulin A/immunology , Immunoglobulin G/blood , Immunoglobulin G/immunology , Immunoglobulin M/blood , Immunoglobulin M/immunology , Male , Middle Aged , Pandemics , Pneumonia, Viral/virology , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/chemistry
5.
bioRxiv ; 2020 Sep 27.
Article in English | MEDLINE | ID: covidwho-807634

ABSTRACT

Following emergence in late 2019, SARS-CoV-2 rapidly became pandemic and is presently responsible for millions of infections and hundreds of thousands of deaths worldwide. There is currently no approved vaccine to halt the spread of SARS-CoV-2 and only very few treatment options are available to manage COVID-19 patients. For development of preclinical countermeasures, reliable and well-characterized small animal disease models will be of paramount importance. Here we show that intranasal inoculation of SARS-CoV-2 into Syrian hamsters consistently caused moderate broncho-interstitial pneumonia, with high viral lung loads and extensive virus shedding, but animals only displayed transient mild disease. We determined the infectious dose 50 to be only five infectious particles, making the Syrian hamster a highly susceptible model for SARS-CoV-2 infection. Neither hamster age nor sex had any impact on the severity of disease or course of infection. Finally, prolonged viral persistence in interleukin 2 receptor gamma chain knockout hamsters revealed susceptibility of SARS-CoV-2 to adaptive immune control. In conclusion, the Syrian hamster is highly susceptible to SARS-CoV-2 making it a very suitable infection model for COVID-19 countermeasure development.

6.
Environ Res ; 191: 110092, 2020 12.
Article in English | MEDLINE | ID: covidwho-731769

ABSTRACT

Wastewater-based epidemiology (WBE) demonstrates potential for COVID-19 community transmission monitoring; however, data on the stability of SARS-CoV-2 RNA in wastewater are needed to interpret WBE results. The decay rates of RNA from SARS-CoV-2 and a potential surrogate, murine hepatitis virus (MHV), were investigated by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) in untreated wastewater, autoclaved wastewater, and dechlorinated tap water stored at 4, 15, 25, and 37 °C. Temperature, followed by matrix type, most greatly influenced SARS-CoV-2 RNA first-order decay rates (k). The average T90 (time required for 1-log10 reduction) of SARS-CoV-2 RNA ranged from 8.04 to 27.8 days in untreated wastewater, 5.71 to 43.2 days in autoclaved wastewater, and 9.40 to 58.6 days in tap water. The average T90 for RNA of MHV at 4 to 37 °C ranged from 7.44 to 56.6 days in untreated wastewater, 5.58-43.1 days in autoclaved wastewater, and 10.9 to 43.9 days in tap water. There was no statistically significant difference between RNA decay of SARS-CoV-2 and MHV; thus, MHV is suggested as a suitable persistence surrogate. Decay rate constants for all temperatures were comparable across all matrices for both viral RNAs, except in untreated wastewater for SARS-CoV-2, which showed less sensitivity to elevated temperatures. Therefore, SARS-CoV-2 RNA is likely to persist long enough in untreated wastewater to permit reliable detection for WBE application.


Subject(s)
Coronavirus Infections , Murine hepatitis virus , Pandemics , Pneumonia, Viral , Animals , Betacoronavirus , COVID-19 , Humans , Mice , SARS-CoV-2 , Waste Water , Wastewater-Based Epidemiological Monitoring
7.
Transfusion ; 60(12): 2962-2968, 2020 12.
Article in English | MEDLINE | ID: covidwho-729351

ABSTRACT

BACKGROUND: Nucleic acid persists after symptom resolution and infectivity for many viral infections via delayed clearance of nucleic acid fragments, non-infectious particles, or transmissible virus. For Coronavirus Disease 2019 (COVID-19), the relationship between nasopharyngeal (NP) swab positivity, the development of antibodies against COVID-19, and clinical history are unclear. STUDY DESIGN AND METHODS: Individuals who recovered from COVID-19 and volunteered to donate convalescent plasma (CP) were screened by NP swab PCR, responded to a questionnaire, and were tested for anti-COVID-19 antibodies. RESULTS: A proportion of 11.8% of individuals tested positive for SARS-CoV-2 by NP swab PCR greater than 14 days after the resolution of symptoms of active disease, including one donor who had asymptomatic disease and tested positive by NP swab 41 days after her initial diagnosis. Clinical history did not show a significant correlation with persistence of NP swab positivity. Also, NP swab positivity >14 days from symptom resolution did not correlate with anti-COVID-19 serology results. IgG anti-SARS-CoV-2 spike antibody strength correlated with hospitalization for COVID-19 using two different assays. Total anti-SARS-CoV-2 nucleocapsid antibody strength correlated with time from symptom resolution to sample collection and symptom duration. CONCLUSIONS: SARS-CoV-2 nucleic acid is detectable long after the resolution of symptoms in a significant percentage of previously diagnosed individuals, which is important to consider when interpreting PCR swab results. Persistence of PCR positivity does not correlate with antibody strength or symptoms of COVID-19. If anti-spike antibody is used to assess CP potency, individuals who suffered severe COVID-19 disease symptoms may represent better donors.


Subject(s)
Blood Donors , COVID-19 Nucleic Acid Testing , COVID-19/therapy , COVID-19/virology , Donor Selection , Nasopharynx/virology , RNA, Viral/isolation & purification , Reverse Transcriptase Polymerase Chain Reaction , SARS-CoV-2/isolation & purification , Adult , Aged , Antibodies, Viral/blood , COVID-19/blood , COVID-19 Serological Testing , Convalescence , Female , Humans , Immunization, Passive , Immunoglobulin G/blood , Male , Middle Aged , SARS-CoV-2/immunology , Symptom Assessment , Young Adult
8.
Math Biosci ; 328: 108438, 2020 10.
Article in English | MEDLINE | ID: covidwho-696903

ABSTRACT

Coronavirus disease 2019 (COVID-19), an infectious disease caused by the infection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is spreading and causing the global coronavirus pandemic. The viral dynamics of SARS-CoV-2 infection have not been quantitatively investigated. In this paper, we use mathematical models to study the pathogenic features of SARS-CoV-2 infection by examining the interaction between the virus, cells and immune responses. Models are fit to the data of SARS-CoV-2 infection in patients and non-human primates. Data fitting and numerical simulation show that viral dynamics of SARS-CoV-2 infection have a few distinct stages. In the initial stage, viral load increases rapidly and reaches the peak, followed by a plateau phase possibly generated by lymphocytes as a secondary target of infection. In the last stage, viral load declines due to the emergence of adaptive immune responses. When the initiation of seroconversion is late or slow, the model predicts viral rebound and prolonged viral persistence, consistent with the observation in non-human primates. Using the model we also evaluate the effect of several potential therapeutic interventions for SARS-CoV-2 infection. Model simulation shows that anti-inflammatory treatments or antiviral drugs combined with interferon are effective in reducing the duration of the viral plateau phase and diminishing the time to recovery. These results provide insights for understanding the infection dynamics and might help develop treatment strategies against COVID-19.


Subject(s)
Betacoronavirus , Coronavirus Infections/virology , Models, Biological , Pneumonia, Viral/virology , Adaptive Immunity , Animals , Betacoronavirus/drug effects , Betacoronavirus/genetics , Betacoronavirus/immunology , COVID-19 , Coronavirus Infections/drug therapy , Coronavirus Infections/epidemiology , Coronavirus Infections/immunology , Host Microbial Interactions/immunology , Humans , Macaca mulatta , Mathematical Concepts , Pandemics , Pneumonia, Viral/epidemiology , Pneumonia, Viral/immunology , RNA, Viral/analysis , RNA, Viral/genetics , SARS-CoV-2 , Viral Load
9.
EBioMedicine ; 59: 102915, 2020 Sep.
Article in English | MEDLINE | ID: covidwho-691414

ABSTRACT

BACKGROUND: The serologic response of individuals with mild forms of SARS-CoV-2 infection is poorly characterized. METHODS: Hospital staff who had recovered from mild forms of PCR-confirmed SARS-CoV-2 infection were tested for anti-SARS-CoV-2 antibodies using two assays: a rapid immunodiagnostic test (99.4% specificity) and the S-Flow assay (~99% specificity). The neutralizing activity of the sera was tested with a pseudovirus-based assay. FINDINGS: Of 162 hospital staff who participated in the investigation, 160 reported SARS-CoV-2 infection that had not required hospital admission and were included in these analyses. The median time from symptom onset to blood sample collection was 24 days (IQR: 21-28, range 13-39). The rapid immunodiagnostic test detected antibodies in 153 (95.6%) of the samples and the S-Flow assay in 159 (99.4%), failing to detect antibodies in one sample collected 18 days after symptom onset (the rapid test did not detect antibodies in that patient). Neutralizing antibodies (NAbs) were detected in 79%, 92% and 98% of samples collected 13-20, 21-27 and 28-41 days after symptom onset, respectively (P = 0.02). INTERPRETATION: Antibodies against SARS-CoV-2 were detected in virtually all hospital staff sampled from 13 days after the onset of COVID-19 symptoms. This finding supports the use of serologic testing for the diagnosis of individuals who have recovered from SARS-CoV-2 infection. The neutralizing activity of the antibodies increased overtime. Future studies will help assess the persistence of the humoral response and its associated neutralization capacity in recovered patients. FUNDINGS: The funders had no role in study design, data collection, interpretation, or the decision to submit the work for publication.


Subject(s)
Antibodies, Viral/blood , Coronavirus Infections/diagnosis , Pneumonia, Viral/diagnosis , Adult , Antibodies, Neutralizing/blood , Betacoronavirus/genetics , Betacoronavirus/isolation & purification , COVID-19 , Coronavirus Infections/pathology , Coronavirus Infections/virology , Female , France , Health Personnel , Hospitals , Humans , Male , Middle Aged , Pandemics , Pneumonia, Viral/pathology , Pneumonia, Viral/virology , RNA, Viral/metabolism , Reverse Transcriptase Polymerase Chain Reaction , SARS-CoV-2 , Serologic Tests , Severity of Illness Index
10.
Cureus ; 12(7): e9048, 2020 Jul 07.
Article in English | MEDLINE | ID: covidwho-664065

ABSTRACT

In the world scenario, the advent of COVID-19 has halted every aspect of life. It influenced every field of life, including the economy, and revealed the inadequacies in all nations' healthcare systems, from the most developed to the underdeveloped countries. There is a debate about the timing of antibodies production and detection during the disease. What is the significance of reverse transcription-polymerase chain reaction (RT-PCR) viral ribonucleic acid (RNA) in symptom resolving period? In the present manuscript, we have evaluated these points.

11.
QJM ; 113(8): 556-560, 2020 Aug 01.
Article in English | MEDLINE | ID: covidwho-627185

ABSTRACT

BACKGROUND: Duration of persistence of SARS-CoV-2 in the upper respiratory tract of infected individuals has important clinical and epidemiological implications. AIM: We aimed to establish the duration and risk factors for persistence of SARS-CoV-2 in the upper respiratory tract of asymptomatic infected individuals. METHODS: Data of repeat rRT-PCR (real-time reverse transcription-polymerase chain reaction) test done for SARS-CoV-2 infected individuals at our institute at Jodhpur, India were analysed from 19 March to 21 May 2020. Duration of virus persistence was estimated with parametric regression models based on weibull, log-normal, log-logistic, gamma and generalized gamma distributions. Factors associated with prolonged viral persistence were analysed with the best-fitting model. RESULTS: Fifty-one SARS-CoV-2 infected individuals with repeat rRT-PCR test were identified with 44 asymptomatics. The asymptomatic individuals had median virus persistence duration of 8.87 days (95% CI: 7.65-10.27) and 95 percentile duration of 20.70 days (95% CI: 16.08-28.20). The overall median virus persistence including both symptomatic and asymptomatic individuals was found to be 9.18 days (95% CI: 8.04-10.48). Around one-fourth asymptomatics (10/44) demonstrated SARS-CoV-2 persistence beyond 2 weeks. Age <60 years and local transmission were found to be significantly associated with longer virus persistence among asymptomatic individuals on univariate regression but not in multivariate analysis. CONCLUSION: Recommended home isolation duration for SARS-CoV-2 infected individuals in India should be extended from 17 days to at least 3 weeks. Prolonged persistence of SARS-CoV-2 in a considerable proportion of asymptomatic individuals merits attention with regard to ensuring universal infection prevention precautions irrespective of symptomatic status.


Subject(s)
Asymptomatic Infections , Betacoronavirus/isolation & purification , Coronavirus Infections/virology , Nasopharynx/virology , Oropharynx/virology , Pneumonia, Viral/virology , Adolescent , Adult , Age Factors , Aged , COVID-19 , COVID-19 Testing , Clinical Laboratory Techniques/methods , Coronavirus Infections/diagnosis , Coronavirus Infections/transmission , Female , Humans , India , Male , Middle Aged , Pandemics , Pneumonia, Viral/diagnosis , Pneumonia, Viral/transmission , Reverse Transcriptase Polymerase Chain Reaction/methods , Risk Factors , SARS-CoV-2 , Time Factors , Virus Shedding , Young Adult
15.
Sci Rep ; 10(1): 7257, 2020 04 29.
Article in English | MEDLINE | ID: covidwho-154662

ABSTRACT

Coronaviruses that cause severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) are speculated to have originated in bats. The mechanisms by which these viruses are maintained in individuals or populations of reservoir bats remain an enigma. Mathematical models have predicted long-term persistent infection with low levels of periodic shedding as a likely route for virus maintenance and spillover from bats. In this study, we tested the hypothesis that bat cells and MERS coronavirus (CoV) can co-exist in vitro. To test our hypothesis, we established a long-term coronavirus infection model of bat cells that are persistently infected with MERS-CoV. We infected cells from Eptesicus fuscus with MERS-CoV and maintained them in culture for at least 126 days. We characterized the persistently infected cells by detecting virus particles, protein and transcripts. Basal levels of type I interferon in the long-term infected bat cells were higher, relative to uninfected cells, and disrupting the interferon response in persistently infected bat cells increased virus replication. By sequencing the whole genome of MERS-CoV from persistently infected bat cells, we identified that bat cells repeatedly selected for viral variants that contained mutations in the viral open reading frame 5 (ORF5) protein. Furthermore, bat cells that were persistently infected with ΔORF5 MERS-CoV were resistant to superinfection by wildtype virus, likely due to reduced levels of the virus receptor, dipeptidyl peptidase 4 (DPP4) and higher basal levels of interferon in these cells. In summary, our study provides evidence for a model of coronavirus persistence in bats, along with the establishment of a unique persistently infected cell culture model to study MERS-CoV-bat interactions.


Subject(s)
Chiroptera/virology , Coronavirus Infections/virology , Fibroblasts/virology , Middle East Respiratory Syndrome Coronavirus/genetics , Open Reading Frames/genetics , Point Mutation , Animals , Chiroptera/anatomy & histology , Chlorocebus aethiops , Coronavirus Nucleocapsid Proteins , Dipeptidyl Peptidase 4/metabolism , Fibroblasts/metabolism , Genome, Viral/genetics , Humans , Interferon Regulatory Factor-3/genetics , Interferon Regulatory Factor-3/metabolism , Interferon Type I/metabolism , Kidney/cytology , Mitogen-Activated Protein Kinases/genetics , Mitogen-Activated Protein Kinases/metabolism , Nucleocapsid Proteins/genetics , Receptors, Virus/metabolism , Transfection , Vero Cells , Virus Replication/genetics , Whole Genome Sequencing
16.
Chin Med J (Engl) ; 133(9): 1039-1043, 2020 May 05.
Article in English | MEDLINE | ID: covidwho-10492

ABSTRACT

BACKGROUND: A patient's infectivity is determined by the presence of the virus in different body fluids, secretions, and excreta. The persistence and clearance of viral RNA from different specimens of patients with 2019 novel coronavirus disease (COVID-19) remain unclear. This study analyzed the clearance time and factors influencing 2019 novel coronavirus (2019-nCoV) RNA in different samples from patients with COVID-19, providing further evidence to improve the management of patients during convalescence. METHODS: The clinical data and laboratory test results of convalescent patients with COVID-19 who were admitted to from January 20, 2020 to February 10, 2020 were collected retrospectively. The reverse transcription polymerase chain reaction (RT-PCR) results for patients' oropharyngeal swab, stool, urine, and serum samples were collected and analyzed. Convalescent patients refer to recovered non-febrile patients without respiratory symptoms who had two successive (minimum 24 h sampling interval) negative RT-PCR results for viral RNA from oropharyngeal swabs. The effects of cluster of differentiation 4 (CD4)+ T lymphocytes, inflammatory indicators, and glucocorticoid treatment on viral nucleic acid clearance were analyzed. RESULTS: In the 292 confirmed cases, 66 patients recovered after treatment and were included in our study. In total, 28 (42.4%) women and 38 men (57.6%) with a median age of 44.0 (34.0-62.0) years were analyzed. After in-hospital treatment, patients' inflammatory indicators decreased with improved clinical condition. The median time from the onset of symptoms to first negative RT-PCR results for oropharyngeal swabs in convalescent patients was 9.5 (6.0-11.0) days. By February 10, 2020, 11 convalescent patients (16.7%) still tested positive for viral RNA from stool specimens and the other 55 patients' stool specimens were negative for 2019-nCoV following a median duration of 11.0 (9.0-16.0) days after symptom onset. Among these 55 patients, 43 had a longer duration until stool specimens were negative for viral RNA than for throat swabs, with a median delay of 2.0 (1.0-4.0) days. Results for only four (6.9%) urine samples were positive for viral nucleic acid out of 58 cases; viral RNA was still present in three patients' urine specimens after throat swabs were negative. Using a multiple linear regression model (F = 2.669, P = 0.044, and adjusted R = 0.122), the analysis showed that the CD4+ T lymphocyte count may help predict the duration of viral RNA detection in patients' stools (t = -2.699, P = 0.010). The duration of viral RNA detection from oropharyngeal swabs and fecal samples in the glucocorticoid treatment group was longer than that in the non-glucocorticoid treatment group (15 days vs. 8.0 days, respectively; t = 2.550, P = 0.013) and the duration of viral RNA detection in fecal samples in the glucocorticoid treatment group was longer than that in the non-glucocorticoid treatment group (20 days vs. 11 days, respectively; t = 4.631, P < 0.001). There was no statistically significant difference in inflammatory indicators between patients with positive fecal viral RNA test results and those with negative results (P > 0.05). CONCLUSIONS: In brief, as the clearance of viral RNA in patients' stools was delayed compared to that in oropharyngeal swabs, it is important to identify viral RNA in feces during convalescence. Because of the delayed clearance of viral RNA in the glucocorticoid treatment group, glucocorticoids are not recommended in the treatment of COVID-19, especially for mild disease. The duration of RNA detection may relate to host cell immunity.


Subject(s)
Betacoronavirus/genetics , Coronavirus Infections/genetics , Pneumonia, Viral/genetics , RNA, Viral/genetics , Adult , Aged , COVID-19 , COVID-19 Testing , Clinical Laboratory Techniques , Coronavirus Infections/diagnosis , Coronavirus Infections/rehabilitation , Female , Humans , Male , Middle Aged , Pandemics , Pneumonia, Viral/rehabilitation , Real-Time Polymerase Chain Reaction , Retrospective Studies , SARS-CoV-2
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