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1.
Nat Commun ; 12(1): 4043, 2021 06 30.
Article in English | MEDLINE | ID: covidwho-1290767

ABSTRACT

Memory T cells contribute to rapid viral clearance during re-infection, but the longevity and differentiation of SARS-CoV-2-specific memory T cells remain unclear. Here we conduct ex vivo assays to evaluate SARS-CoV-2-specific CD4+ and CD8+ T cell responses in COVID-19 convalescent patients up to 317 days post-symptom onset (DPSO), and find that memory T cell responses are maintained during the study period regardless of the severity of COVID-19. In particular, we observe sustained polyfunctionality and proliferation capacity of SARS-CoV-2-specific T cells. Among SARS-CoV-2-specific CD4+ and CD8+ T cells detected by activation-induced markers, the proportion of stem cell-like memory T (TSCM) cells is increased, peaking at approximately 120 DPSO. Development of TSCM cells is confirmed by SARS-CoV-2-specific MHC-I multimer staining. Considering the self-renewal capacity and multipotency of TSCM cells, our data suggest that SARS-CoV-2-specific T cells are long-lasting after recovery from COVID-19, thus support the feasibility of effective vaccination programs as a measure for COVID-19 control.


Subject(s)
CD4-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , COVID-19/immunology , Immunologic Memory/immunology , SARS-CoV-2/immunology , Antibodies, Viral/blood , COVID-19 Vaccines/immunology , Enzyme-Linked Immunosorbent Assay , Humans , Interferon-gamma/blood , Vaccination
2.
Infect Control Hosp Epidemiol ; 43(2): 232-237, 2022 02.
Article in English | MEDLINE | ID: covidwho-1246285

ABSTRACT

OBJECTIVE: To investigate the feasibility of using an ultraviolet light-emitting diode (UV LED) robot for the terminal decontamination of coronavirus disease 2019 (COVID-19) patient rooms. METHODS: We assessed the presence of viral RNA in samples from environmental surfaces before and after UV LED irradiation in COVID-19 patient rooms after patient discharge. RESULTS: We analyzed 216 environmental samples from 17 rooms: 2 from airborne infection isolation rooms (AIIRs) in the intensive care unit (ICU) and 15 from isolation rooms in the community treatment center (CTC). Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA was detected in 40 (18.5%) of 216 samples after patient discharge: 12 (33.3%) of 36 samples from AIIRs in the ICU, and 28 (15.6%) of 180 samples from isolation rooms in the CTC. In 1 AIIR, all samples were PCR negative after UV LED irradiation. In the CTC rooms, 14 (8.6%) of the 163 samples were PCR positive after UV LED irradiation. However, viable virus was not recovered from the culture of any of the PCR-positive samples. CONCLUSIONS: Although no viable virus was recovered, SARS-CoV-2 RNA was detected on various environmental surfaces. The use of a UV LED disinfection robot was effective in spacious areas such as an ICU, but its effects varied in small spaces like CTC rooms. These findings suggest that the UV LED robot may need enough space to disinfect rooms without recontamination by machine wheels or insufficient disinfection by shadowing.


Subject(s)
COVID-19 , Robotics , Decontamination , Disinfection , Feasibility Studies , Humans , Patients' Rooms , RNA, Viral , SARS-CoV-2 , Ultraviolet Rays
3.
PLoS One ; 16(4): e0250358, 2021.
Article in English | MEDLINE | ID: covidwho-1197390

ABSTRACT

Few studies have focused on clinical courses or viral loads in young asymptomatic or mild patients with COVID-19 infection. We sought to better understand the clinical course and association between viral load and prevalence of pneumonia in young COVID-19 patients with asymptomatic or mild disease severity. In this retrospective study, 106 COVID-19 young patients with asymptomatic or mild disease severity were analyzed for clinical characteristics, clinical course, prevalence of radiologically proven pneumonia and viral load. The cut-off value of viral load for presence of pneumonia was also investigated. The mean age was 28.0±9.3 years. Eleven patients (10.4%) experienced viral remission within one week of diagnosis, but one (0.9%) transferred to the hospital due to aggravation of pneumonia. Patients with pneumonia had significantly higher viral load than those without, and the cut-off value of the Ct value for presence of pneumonia were 31.38. The patients with pneumonia had significantly slower recovery times than those without. Diarrhea was significantly more common in patients with pneumonia than patients without pneumonia. In conclusion, most young asymptomatic and mildly symptomatic patients showed stable clinical course. There were significant differences in viral load and recovery times between patients with and without pneumonia.


Subject(s)
Asymptomatic Diseases/epidemiology , COVID-19/epidemiology , Pneumonia/epidemiology , Adolescent , Adult , COVID-19/metabolism , Female , Humans , Male , Prevalence , Republic of Korea , Retrospective Studies , SARS-CoV-2/isolation & purification , Serologic Tests , Severity of Illness Index , Viral Load/methods , Young Adult
4.
Immunity ; 54(1): 44-52.e3, 2021 01 12.
Article in English | MEDLINE | ID: covidwho-1065202

ABSTRACT

Memory T cell responses have been demonstrated in COVID-19 convalescents, but ex vivo phenotypes of SARS-CoV-2-specific T cells have been unclear. We detected SARS-CoV-2-specific CD8+ T cells by MHC class I multimer staining and examined their phenotypes and functions in acute and convalescent COVID-19. Multimer+ cells exhibited early differentiated effector-memory phenotypes in the early convalescent phase. The frequency of stem-like memory cells was increased among multimer+ cells in the late convalescent phase. Cytokine secretion assays combined with MHC class I multimer staining revealed that the proportion of interferon-γ (IFN-γ)-producing cells was significantly lower among SARS-CoV-2-specific CD8+ T cells than those specific to influenza A virus. Importantly, the proportion of IFN-γ-producing cells was higher in PD-1+ cells than PD-1- cells among multimer+ cells, indicating that PD-1-expressing, SARS-CoV-2-specific CD8+ T cells are not exhausted, but functional. Our current findings provide information for understanding of SARS-CoV-2-specific CD8+ T cells elicited by infection or vaccination.


Subject(s)
CD8-Positive T-Lymphocytes/immunology , COVID-19/immunology , Programmed Cell Death 1 Receptor/metabolism , SARS-CoV-2/immunology , Acute-Phase Reaction/immunology , Acute-Phase Reaction/virology , COVID-19/pathology , COVID-19/virology , Convalescence , Epitopes, T-Lymphocyte , Histocompatibility Antigens Class I/immunology , Humans , Immunologic Memory , Immunophenotyping , Interferon-gamma/metabolism , Lymphocyte Activation , Viral Load
5.
Immunity ; 54(1): 44-52.e3, 2021 01 12.
Article in English | MEDLINE | ID: covidwho-988082

ABSTRACT

Memory T cell responses have been demonstrated in COVID-19 convalescents, but ex vivo phenotypes of SARS-CoV-2-specific T cells have been unclear. We detected SARS-CoV-2-specific CD8+ T cells by MHC class I multimer staining and examined their phenotypes and functions in acute and convalescent COVID-19. Multimer+ cells exhibited early differentiated effector-memory phenotypes in the early convalescent phase. The frequency of stem-like memory cells was increased among multimer+ cells in the late convalescent phase. Cytokine secretion assays combined with MHC class I multimer staining revealed that the proportion of interferon-γ (IFN-γ)-producing cells was significantly lower among SARS-CoV-2-specific CD8+ T cells than those specific to influenza A virus. Importantly, the proportion of IFN-γ-producing cells was higher in PD-1+ cells than PD-1- cells among multimer+ cells, indicating that PD-1-expressing, SARS-CoV-2-specific CD8+ T cells are not exhausted, but functional. Our current findings provide information for understanding of SARS-CoV-2-specific CD8+ T cells elicited by infection or vaccination.


Subject(s)
CD8-Positive T-Lymphocytes/immunology , COVID-19/immunology , Programmed Cell Death 1 Receptor/metabolism , SARS-CoV-2/immunology , Acute-Phase Reaction/immunology , Acute-Phase Reaction/virology , COVID-19/pathology , COVID-19/virology , Convalescence , Epitopes, T-Lymphocyte , Histocompatibility Antigens Class I/immunology , Humans , Immunologic Memory , Immunophenotyping , Interferon-gamma/metabolism , Lymphocyte Activation , Viral Load
6.
J Korean Med Sci ; 35(41): e375, 2020 Oct 26.
Article in English | MEDLINE | ID: covidwho-892421

ABSTRACT

BACKGROUND: Olfactory and gustatory dysfunction has been reported as characteristic symptoms of coronavirus disease 2019 (COVID-19). This study evaluated olfactory and gustatory dysfunction in mild COVID-19 patients using validated assessment methods. METHODS: A prospective surveillance study was conducted for mild COVID-19 patients who were isolated at the Gyeonggi International Living and Treatment Support Center (LTSC), Korea. Olfactory function was assessed using the Korean version of the Questionnaire of Olfactory Disorders (QOD) and Cross-Cultural Smell Identification Test (CC-SIT). Gustatory function was assessed using an 11-point Likert scale and 6-n-propylthiouracil, phenylthiocarbamide, and control strips. All patients underwent nasal and oral cavity endoscopic examination. RESULTS: Of the 62 patients at the LTSC, 15 patients (24.2%) complained of olfactory or gustatory dysfunction on admission. Four of 10 patients who underwent functional evaluation did not have general symptoms and 2 were asymptomatic. The mean short version of QOD-negative statements and QOD-visual analogue scale scores were 13 ± 6 and 4.7 ± 3.6, respectively. The mean CC-SIT score was 8 ± 2. No patients showed anatomical abnormalities associated with olfactory dysfunction on endoscopic examination. The mean Likert scale score for function was 8 ± 2, and there were no abnormal lesions in the oral cavity of any patient. CONCLUSIONS: The prevalence of olfactory and gustatory dysfunction was 24.2% in mild COVID-19 patients. All patients had hyposmia due to sensorineural olfactory dysfunction, which was confirmed using validated olfactory and gustatory evaluation methods and endoscopic examination. Olfactory and gustatory dysfunction may be characteristic indicators of mild COVID-19.


Subject(s)
Coronavirus Infections/physiopathology , Olfaction Disorders/physiopathology , Pneumonia, Viral/physiopathology , Symptom Assessment/methods , Taste Disorders/physiopathology , Adult , Betacoronavirus , COVID-19 , Coronavirus Infections/therapy , Cultural Characteristics , Endoscopy , Female , Humans , Male , Middle Aged , Pandemics , Pneumonia, Viral/therapy , Prospective Studies , Quarantine , Reproducibility of Results , Republic of Korea , SARS-CoV-2 , Smell , Surveys and Questionnaires , Young Adult
7.
SSRN; 2020.
Preprint | SSRN | ID: ppcovidwho-1439

ABSTRACT

Background: Olfactory and gustatory dysfunction have been reported as characteristic symptoms of coronavirus disease 2019 (COVID-19). This study evaluated olfa

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