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2.
J Korean Med Sci ; 37(16): e126, 2022 Apr 25.
Article in English | MEDLINE | ID: covidwho-1809347

ABSTRACT

BACKGROUND: The relationship between changes in anxiety levels and personal protective equipment (PPE) use is yet to be evaluated. The present study assessed this relationship among healthcare workers (HCWs) involved in the care of patients with coronavirus disease 2019 (COVID-19). METHODS: An online survey was conducted in a municipal hospital with 195 nationally designated negative pressure isolation units in Korea. Anxiety level was measured using the self-rating anxiety scale (SAS), and changes in anxiety levels were assessed based on the time when COVID-19 vaccine was introduced in March 2021 in Korea. Monthly PPE usage between June 2020 and May 2021 was investigated. RESULTS: The mean SAS score (33.25 ± 5.97) was within normal range and was lower than those reported in previous studies conducted before COVID-19 vaccination became available. Among the 93 HCWs who participated, 64 (68.8%) answered that their fear of contracting COVID-19 decreased after vaccination. The number of coveralls used per patient decreased from 33.6 to 0. However, a demand for more PPE than necessary was observed in situations where HCWs were exposed to body fluids and secretions (n = 38, 40.9%). Excessive demand for PPE was not related to age, working experience, or SAS score. CONCLUSION: Anxiety in HCWs exposed to COVID-19 was lower than it was during the early period of the pandemic, and the period before vaccination was introduced. The number of coveralls used per patient also decreased although an excessive demand for PPE was observed.


Subject(s)
COVID-19 , Personal Protective Equipment , Anxiety/epidemiology , COVID-19/epidemiology , COVID-19/prevention & control , COVID-19 Vaccines , Health Personnel , Humans , SARS-CoV-2
3.
PLoS One ; 17(3): e0264711, 2022.
Article in English | MEDLINE | ID: covidwho-1793510

ABSTRACT

Reports detailing the clinical characteristics, viral load, and outcomes of patients with normal initial chest CT findings are lacking. We sought to compare the differences in clinical findings, viral loads, and outcomes between patients with confirmed COVID-19 who initially tested negative on chest CT (CT negative) with patients who tested initially positive on chest CT (CT positive). The clinical data, viral loads, and outcomes of initial CT-positive and CT-negative patients examined between January 2020 and April 2020 were retrospectively compared. The efficacy of viral load (cyclic threshold value [Ct value]) in predicting pneumonia was evaluated using receiver operating characteristic (ROC) curve and area under the curve (AUC). In total, 128 patients underwent initial chest CT (mean age, 54.3 ± 19.0 years, 50% male). Of those, 36 were initially CT negative, and 92 were CT positive. The CT-positive patients were significantly older (P < .001) than the CT-negative patients. Only age was significantly associated with the initial presence of pneumonia (odds ratio, 1.060; confidence interval (CI), 1.020-1-102; P = .003). In addition, age (OR, 1.062; CI, 1.014-1.112; P = .011), fever at diagnosis (OR, 6.689; CI, 1.715-26.096; P = .006), and CRP level (OR, 1.393; CI, 1.150-1.687; P = .001) were significantly associated with the need for O2 therapy. Viral load was significantly higher in the CT-positive group than in the CT-negative group (P = .017). The cutoff Ct value for predicting the presence of pneumonia was 27.71. Outcomes including the mean hospital stay, intensive care unit admission, and O2 therapy were significantly worse in the CT-positive group than in the CT-negative group (all P < .05). In conclusion, initially CT-negative patients showed better outcomes than initially CT-positive patients. Age was significantly associated with the initial presence of pneumonia, and viral load may help in predicting the initial presence of pneumonia.


Subject(s)
COVID-19/diagnosis , Thorax/diagnostic imaging , Viral Load , Adult , Aged , COVID-19/epidemiology , COVID-19/virology , Female , Humans , Male , Middle Aged , Predictive Value of Tests , Prognosis , Republic of Korea/epidemiology , Retrospective Studies , SARS-CoV-2 , Sputum/virology , Tomography, X-Ray Computed , Viral Load/physiology , Young Adult
4.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-321830

ABSTRACT

Background: During the COVID-19 pandemic, people have been required to follow preventive measures such as government policy including the closure of exercise facilities and movement restriction, can lead to an unhealthy lifestyle. We investigated the effect of these preventive measures on metabolic parameters in individuals with cardiometabolic disorders. Methods: In the current retrospective observational study of patients who visited the hospital at least twice a year for the past 4 years, changes in cardiometabolic factors from the COVID-19 pandemic (2019–2020) were compared with changes in the same cohort at the same annual time points during the previous seasons of 2016–2019. Results: A total of 1,485 individuals with a mean age of 61.8 ± 11.7 years were included in the analysis. During the COVID-19 pandemic, the number of patients whose metabolic syndrome worsened increased significantly by 21% compared with the 2018–2019 season. The body mass index increased by 0.09 ± 1.16 kg/m2 in the 2019–2020 pandemic period, whereas it decreased by –0.39 ± 3.03 kg/m2 in 2018–2019 and by –0.34 ± 2.18 kg/m2 in 2017–2018 (both p < 0.05). Systolic blood pressure increased by 2.6 ± 18.2 mmHg in the COVID-19 pandemic period, while it decreased in the three antecedent seasons (all p < 0.05). The lipid profiles worsened in the pandemic period compared with the previous years. The Framingham coronary heart disease risk score also increased significantly. Conclusions: With preventive procedures during the contagious disease pandemic, nationwide strategies to maintain cardiometabolic health are necessary.

5.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-320007

ABSTRACT

Memory T-cell responses have been demonstrated after recovery from SARS-CoV-2 infection, but the phenotypes of SARS-CoV-2-specific T cells have not been comprehensively investigated ex vivo. We detected SARS-CoV-2-specific CD8+ T cells by MHC-I multimer staining and examined their phenotypes in relation to their functional capacity in acute and convalescent COVID-19. In the convalescent phase, multimer+ cells exhibited early differentiated effector-memory phenotypes. The frequency of CD127+KLRG1- memory precursor effector cells among multimer+ cells was significantly lower in convalescent individuals with severe disease than those with mild disease. Cytokine-secretion assays combined with MHC-I multimer staining revealed that the proportion of IFN-γ-producing cells was significantly lower among SARS-CoV-2-specific CD8+ T cells than those specific to other viruses. Importantly, the proportion of IFN-γ-producing cells was significantly higher in PD-1+ cells than PD-1- cells among multimer+ cells in both the acute and convalescence phases, indicating that PD-1-expressing, SARS-CoV-2-specific CD8+ T cells are not exhausted, but functional. Our findings provide insights for effective vaccine development.

6.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-313588

ABSTRACT

Objectives: Few studies have investigated the contamination of personal protective equipment (PPE) during the management of patients with severe to critical coronavirus disease (COVID-19). This study aimed to determine the necessity of coveralls and foot cover for body protection during the management of patients with COVID-19. Methods PPE samples were collected from physicians exiting a room after the management of a patient with severe to critical COVID-19 who was within 14 days after symptom onset. The PPE sites were categorized into coverall-only parts (the frontal surface of the head, anterior neck, dorsal surface of the foot cover, and back and hip) and gown-covered parts (the anterior side of the forearm and the abdomen). Environmental sampling was performed in patient rooms. We tried to identify significant differences in contamination with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) between the coverall-only and gown-covered parts. Results A total of 105 swabs from PPE and 28 swabs from patient rooms were collected. Of the PPE swabs, only three (2.8 %) swabs from gown-covered parts were contaminated by SARS-CoV-2. However, 23 of the total 28 sites (82.1%) from patient rooms were contaminated. There was significant difference in the contamination of PPE between coverall-only and gown-covered parts (0.0 vs 6.7%, p = 0.022). Conclusions Coverall contamination rarely occurred while managing severe to critical COVID-19 patients residing in negative pressure rooms in the early stages of the illness. Long-sleeved gowns may be used safely in the management of COVID-19 patients.

7.
J Korean Med Sci ; 36(50): e343, 2021 Dec 27.
Article in English | MEDLINE | ID: covidwho-1594418

ABSTRACT

As hospitals cater to elderly and vulnerable patients, a high mortality rate is expected if a coronavirus disease 2019 (COVID-19) outbreak occurs. Consequently, policies to prevent the spread of COVID-19 in hospital settings are essential. This study was conducted to investigate how effectively national and international guidelines provide recommendations for infection control issues in hospitals. After selecting important issues in infection control, we performed a systematic review and analysis of recommendations and guidelines for preventing COVID-19 transmission within medical institutions at national and international levels. We analyzed guidelines from the World Health Organization, Centers for Disease Control and Prevention, European Centre for Disease Prevention and Control, and Korea Disease Control and Prevention Agency. Recent guidelines do not provide specific solutions to infection control issues. Therefore, efforts need to be made to devise consistent advice and guidelines for COVID-19 control.


Subject(s)
COVID-19/prevention & control , Infection Control/methods , Practice Guidelines as Topic , SARS-CoV-2 , Health Personnel , Humans
9.
Open forum infectious diseases ; 8(Suppl 1):S316-S317, 2021.
Article in English | EuropePMC | ID: covidwho-1564302

ABSTRACT

Background Infection control measures against the coronavirus disease 2019 (COVID-19) within a hospital often rely on expert experience and intuition due to the lack of clear guidelines. This study surveyed current strategies for the prevention of the spread of COVID-19 in medical institutions. Methods Upon systematic review of the guidelines at the national level, 14 key topics were selected. Six hospitals were provided an open survey that assessed their responses to these topics between August 11 and 25, 2020. Using these data, an online questionnaire was developed and sent to the infection control teams of 46 hospitals in South Korea. The survey was conducted between January 31, 2021, and February 20, 2021. Results All 46 hospitals responded to the survey, and 24 hospitals (52.2%) had treated 100 or more cases of COVID-19. All hospitals operated screening clinics, and the criteria were respiratory symptoms (100%), fever (97.8%), and epidemiological association (93.5%). It was found that 89.1% (41/46) of hospitals allowed symptomatic patients to visit their general outpatient clinics if fever or respiratory symptoms were not associated with COVID-19. Most hospitals (87.2%;34/39) conducted polymerase chain reaction (PCR) tests for all hospitalized patients. Moreover, 76.1% (35/46) of hospitals implemented preemptive isolation policies for hospitalized patients, of which 97.1% (34/35) were released from isolation after a single negative PCR test. A little over half of the hospitals (58.7%;27/46) treated patients that met the national criteria for release from isolation but consistently had positive PCR results. Of these hospitals, 63% (17/27) used N95/KF94 masks, and 40.7% (11/27) used surgical masks without other personal protective equipment for treating them. Most hospitals (76.9%;20/26) accommodated them in shared rooms when the cycle threshold value of the PCR test was more than a certain value (34.6%;9/26), or after a certain period that satisfied the national criteria (26.9%;7/26). Finally, 76.1% (35/46) of hospitals performed emergency procedures or operations on suspected patients. Table 1. Screening and selective treatment policy to prevent COVID-19 patients from entering the hospital Note Values are presented as number (%) Abbreviations: COVID-19, coronavirus disease 2019;PCR, polymerase chain reaction 1 This question requested the respondent to select multiple items. 2 Suspected cases of COVID-19 include fever, respiratory symptoms, and epidemiological associations with COVID-19 patients. Note Values are presented as number (%) Abbreviations: COVID-19, coronavirus disease 2019;PCR, polymerase chain reaction;PAPR, powered air-purifying respirator;Ct, cycle threshold 1 This question requested the respondent to select multiple items. 2 It includes infectious diseases, pulmonology, and the infection control and prevention office. 3 One hospital that wrote a non-categorical answer for the question was excluded. The hospital made a decision after discussing it with an infectious diseases specialist. Conclusion Various guidelines were being applied by each medical institution, but there was a lack of an explicit set of national guidelines to support them. Disclosures All Authors: No reported disclosures

10.
Antimicrob Resist Infect Control ; 10(1): 164, 2021 11 27.
Article in English | MEDLINE | ID: covidwho-1538091

ABSTRACT

OBJECTIVES: Few studies have investigated the contamination of personal protective equipment (PPE) during the management of patients with severe-to-critical coronavirus disease (COVID-19). This study aimed to determine the necessity of coveralls and foot covers for body protection during the management of COVID-19 patients. METHODS: PPE samples were collected from the coveralls of physicians exiting a room after the management of a patient with severe-to-critical COVID-19 within 14 days after the patient's symptom onset. The surface of coveralls was categorized into coverall-only parts (frontal surface of the head, anterior neck, dorsal surface of the foot cover, and back and hip) and gown-covered parts (the anterior side of the forearm and the abdomen). Sampling of the high-contact surfaces in the patient's environment was performed. We attempted to identify significant differences in contamination with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) between the coverall-only and gown-covered parts. RESULTS: A total of 105 swabs from PPEs and 28 swabs from patient rooms were collected. Of the PPE swabs, only three (2.8%) swabs from the gown-covered parts were contaminated with SARS-CoV-2. However, 23 of the 28 sites (82.1%) from patient rooms were contaminated. There was a significant difference in the contamination of PPE between the coverall-only and gown-covered parts (0.0 vs 10.0%, p = 0.022). CONCLUSIONS: Coverall contamination rarely occurred while managing severe-to-critical COVID-19 patients housed in negative pressure rooms in the early stages of the illness. Long-sleeved gowns may be used in the management of COVID-19 patients.


Subject(s)
COVID-19/prevention & control , Infection Control/instrumentation , Infectious Disease Transmission, Patient-to-Professional/prevention & control , Protective Clothing , Humans , Patient Isolation , Patients' Rooms , Physicians
11.
Microbiol Spectr ; 9(3): e0067221, 2021 12 22.
Article in English | MEDLINE | ID: covidwho-1532977

ABSTRACT

Here, we aimed to investigate the diagnostic value of a serological assay using the nucleocapsid protein developed for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) detection and evaluated its performance using three commercial enzyme-linked immunosorbent assays (ELISAs), namely, Standard E 2019 novel coronavirus disease (COVID-19) total antibody (Ab) ELISA (SD Biosensor), and EDI novel coronavirus COVID-19 IgG and IgM ELISA. A recombinant nucleocapsid protein (rNP) was expressed from plants and Escherichia coli for the detection of serum total Ab. We prospectively collected 141 serum samples from 32 patients with reverse transcription-PCR (RT-PCR)-confirmed COVID-19 and determined the sensitivity and dynamics of their total Ab response. Specificity was evaluated using 158 prepandemic samples. To validate the assays, we evaluated the performance using two different cutoff values. The sensitivity and specificity for each assay were as follows: 92.91% and 94.30% (plant-rNP), 83.69% and 98.73% (SD Biosensor), 75.89% and 98.10% (E. coli-rNP), 76.47% and 100% (EDI-IgG), and 80.39% and 80% (EDI-IgM). The plant-based rNP showed the highest sensitivity and area under the receiver operating characteristic (ROC) curve (0.980) among all the assays (P < 0.05). The seroconversion rate for total Ab increased sequentially with disease progression, with a sensitivity of 100% after 10 to 12 days of post-symptom onset (PSO) for both rNP-plant-based and SD Biosensor ELISAs. After 2 weeks of PSO, the seroconversion rates were >80% and 100% for EDI-IgM and EDI-IgG ELISA, respectively. Seroconversion occurred earlier with rNP plant-based ELISA (5 days PSO) compared with E. coli-based (7 days PSO) and SD Biosensor (8 days PSO) ELISA. We determined that rNP produced in plants enables the robust detection of SARS-CoV-2 total Abs. The assay can be used for serosurvey and complementary diagnosis of COVID-19. IMPORTANCE At present, the principal diagnostic methods for COVID-19 comprise the identification of viral nucleic acid by genetic approaches, including PCR-based techniques or next-generation sequencing. However, there is an urgent need for validated serological assays which are crucial for the understanding of immune responses against SARS-CoV-2. In this study, a highly sensitive and specific serological antibody assay was developed for the detection of SARS-CoV-2 with an overall accuracy of 93.56% using a recombinant nucleoprotein expressed from plants.


Subject(s)
Antibodies, Viral/blood , COVID-19 Testing/methods , COVID-19/diagnosis , Enzyme-Linked Immunosorbent Assay/methods , Nucleocapsid Proteins/immunology , Plant Proteins/immunology , Escherichia coli/genetics , Humans , Immunoglobulin G , Immunoglobulin M , Nucleocapsid , Plant Proteins/genetics , Recombinant Proteins/genetics , Recombinant Proteins/immunology , SARS-CoV-2/isolation & purification , Sensitivity and Specificity , Seroconversion , Tobacco/genetics
12.
Nat Commun ; 12(1): 5975, 2021 10 13.
Article in English | MEDLINE | ID: covidwho-1467103

ABSTRACT

Acquired somatic mutations in hematopoietic stem and progenitor cells (clonal hematopoiesis or CH) are associated with advanced age, increased risk of cardiovascular and malignant diseases, and decreased overall survival. These adverse sequelae may be mediated by altered inflammatory profiles observed in patients with CH. A pro-inflammatory immunologic profile is also associated with worse outcomes of certain infections, including SARS-CoV-2 and its associated disease Covid-19. Whether CH predisposes to severe Covid-19 or other infections is unknown. Among 525 individuals with Covid-19 from Memorial Sloan Kettering (MSK) and the Korean Clonal Hematopoiesis (KoCH) consortia, we show that CH is associated with severe Covid-19 outcomes (OR = 1.85, 95%=1.15-2.99, p = 0.01), in particular CH characterized by non-cancer driver mutations (OR = 2.01, 95% CI = 1.15-3.50, p = 0.01). We further explore the relationship between CH and risk of other infections in 14,211 solid tumor patients at MSK. CH is significantly associated with risk of Clostridium Difficile (HR = 2.01, 95% CI: 1.22-3.30, p = 6×10-3) and Streptococcus/Enterococcus infections (HR = 1.56, 95% CI = 1.15-2.13, p = 5×10-3). These findings suggest a relationship between CH and risk of severe infections that warrants further investigation.


Subject(s)
COVID-19/etiology , COVID-19/pathology , Clonal Hematopoiesis/genetics , Hematopoietic Stem Cells/virology , Adolescent , Adult , Aged , Aged, 80 and over , COVID-19/immunology , Child , Child, Preschool , Clonal Hematopoiesis/immunology , Cohort Studies , Female , Humans , Infant , Infant, Newborn , Male , Middle Aged , Mutation/immunology , Neoplasms/genetics , Risk Factors , SARS-CoV-2 , Severity of Illness Index
14.
J Obes Metab Syndr ; 30(3): 248-260, 2021 Sep 30.
Article in English | MEDLINE | ID: covidwho-1337811

ABSTRACT

BACKGROUND: During the coronavirus disease 2019 (COVID-19) pandemic, preventive measures mandated by government policies have included the closure of exercise facilities and movement restriction, which can lead to an unhealthy lifestyle. We investigated the effect of these preventive measures on metabolic parameters in individuals with cardiometabolic disorders. METHODS: In this retrospective, observational study of patients who visited the hospital at least twice a year for the past 4 years, changes in cardiometabolic factors during the COVID-19 pandemic (2019-2020) were compared with changes in the same cohort at the same annual time points during the previous seasons of 2016-2019. RESULTS: A total of 1,485 individuals with a mean age of 61.8±11.7 years were included in the analyses. During the COVID-19 pandemic, the number of patients whose metabolic syndrome worsened increased significantly by 21% compared with the 2018-2019 season. Body mass index increased by 0.09±1.16 kg/m2 in the 2019-2020 pandemic period, whereas it decreased by -0.39±3.03 kg/m2 in 2018-2019 and by -0.34±2.18 kg/m2 in 2017-2018 (both P<0.05). Systolic blood pressure increased by 2.6±18.2 mmHg in the COVID-19 pandemic period, while it decreased in the three antecedent seasons (all P<0.05). Lipid profiles worsened in the pandemic period compared with the previous years. Framingham coronary heart disease risk score also increased significantly. CONCLUSION: Nationwide strategies to maintain cardiometabolic health are necessary during contagious disease pandemics like COVID-19 to mitigate the adverse health effects of pandemic-preventative strategies.

15.
Clin Infect Dis ; 73(1): e132-e140, 2021 07 01.
Article in English | MEDLINE | ID: covidwho-1290937

ABSTRACT

BACKGROUND: Coronavirus disease 2019 (COVID-19) was introduced in Korea early with a large outbreak in mid-February. We reviewed the public health interventions used during the COVID-19 outbreak and describe the impact on seasonal influenza activity in Korea. METHODS: National response strategies, public health interventions and daily COVID-19-confirmed cases in Korea were reviewed during the pandemic. National influenza surveillance data were compared between 7 sequential seasons. Characteristics of each season, including rate of influenza-like illness (ILI), duration of epidemic, date of termination of epidemic, distribution of influenza virus strain, and hospitalization, were analyzed. RESULTS: After various public health interventions including enforced public education on hand hygiene, cough etiquette, staying at home with respiratory symptoms, universal mask use in public places, refrain from nonessential social activities, and school closures the duration of the influenza epidemic in 2019/2020 decreased by 6-12 weeks and the influenza activity peak rated 49.8 ILIs/1000 visits compared to 71.9-86.2 ILIs/1000 visits in previous seasons. During the period of enforced social distancing from weeks 9-17 of 2020, influenza hospitalization cases were 11.9-26.9-fold lower compared with previous seasons. During the 2019/2020 season, influenza B accounted for only 4%, in contrast to previous seasons in which influenza B accounted for 26.6-54.9% of all cases. CONCLUSIONS: Efforts to activate a high-level national response not only led to a decrease in COVID-19 but also a substantial decrease in seasonal influenza activity. Interventions applied to control COVID-19 may serve as useful strategies for prevention and control of influenza in upcoming seasons.


Subject(s)
COVID-19 , Influenza, Human , Disease Outbreaks , Humans , Influenza, Human/epidemiology , Public Health , Republic of Korea , SARS-CoV-2 , Seasons
17.
Journal of Korean Medical Science ; 35(13):1-12, 2020.
Article in English | Korean Science Index | ID: covidwho-1107042

ABSTRACT

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected pneumonia emerged in Wuhan, China in December 2019. In this retrospective multicenter study, we investigated the clinical course and outcomes of novel coronavirus disease 2019 (COVID-19) from early cases in Republic of Korea.Methods: All of the cases confirmed by real time polymerase chain reaction were enrolled from the 1st to the 28th patient nationwide. Clinical data were collected and analyzed for changes in clinical severity including laboratory, radiological, and virologic dynamics during the progression of illness.Results: The median age was 40 years (range, 20–73 years) and 15 (53.6%) patients were male. The most common symptoms were cough (28.6%) and sore throat (28.6%), followed by fever (25.0%). Diarrhea was not common (10.7%). Two patients had no symptoms. Initial chest X-ray (CXR) showed infiltration in 46.4% of the patients, but computed tomography scan confirmed pneumonia in 88.9% (16/18) of the patients. Six patients (21.4%) required supplemental oxygen therapy, but no one needed mechanical ventilation. Lymphopenia was more common in severe cases. Higher level of C-reactive protein and worsening of chest radiographic score was observed during the 5–7 day period after symptom onset. Viral shedding was high from day 1 of illness, especially from the upper respiratory tract (URT).Conclusion: The prodromal symptoms of COVID-19 were mild and most patients did not have limitations of daily activity. Viral shedding from URT was high from the prodromal phase.Radiological pneumonia was common from the early days of illness, but it was frequently not evident in simple CXR. These findings could be plausible explanations for the easy and rapid spread of SARS-CoV-2 in the community.

18.
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
20.
Sci Transl Med ; 13(578)2021 01 27.
Article in English | MEDLINE | ID: covidwho-1007317

ABSTRACT

Stereotypic antibody clonotypes exist in healthy individuals and may provide protective immunity against viral infections by neutralization. We observed that 13 of 17 patients with COVID-19 had stereotypic variable heavy chain (VH) antibody clonotypes directed against the receptor binding domain (RBD) of SARS-CoV-2 spike protein. These antibody clonotypes were composed of immunoglobulin heavy variable 3-53 (IGHV3-53) or IGHV3-66 and immunoglobulin heavy joining 6 (IGHJ6) genes. These clonotypes included IgM, IgG3, IgG1, IgA1, IgG2, and IgA2 subtypes and had minimal somatic mutations, which suggested swift class switching after SARS-CoV-2 infection. The different IGHV chains were paired with diverse light chains resulting in binding to the RBD of SARS-CoV-2 spike protein. Human antibodies specific for the RBD can neutralize SARS-CoV-2 by inhibiting entry into host cells. We observed that one of these stereotypic neutralizing antibodies could inhibit viral replication in vitro using a clinical isolate of SARS-CoV-2. We also found that these VH clonotypes existed in 6 of 10 healthy individuals, with IgM isotypes predominating. These findings suggest that stereotypic clonotypes can develop de novo from naïve B cells and not from memory B cells established from prior exposure to similar viruses. The expeditious and stereotypic expansion of these clonotypes may have occurred in patients infected with SARS-CoV-2 because they were already present.


Subject(s)
Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19/immunology , Immunoglobulin Heavy Chains/immunology , Immunoglobulin Variable Region/immunology , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/immunology , Antibodies, Neutralizing/isolation & purification , COVID-19/blood , COVID-19/virology , Clone Cells , Enzyme-Linked Immunosorbent Assay , Humans , Immunoglobulin G/blood , Mutation/genetics , Protein Binding , Protein Domains , Recombinant Proteins/metabolism , Spike Glycoprotein, Coronavirus/genetics
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