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1.
Commun Biol ; 5(1): 516, 2022 05 30.
Article in English | MEDLINE | ID: covidwho-1947507

ABSTRACT

The development of an in vitro cell model that can be used to study severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) research is expected. Here we conducted infection experiments in bronchial organoids (BO) and an BO-derived air-liquid interface model (BO-ALI) using 8 SARS-CoV-2 variants. The infection efficiency in BO-ALI was more than 1,000 times higher than that in BO. Among the bronchial epithelial cells, we found that ciliated cells were infected with the virus, but basal cells were not. Ciliated cells died 7 days after the viral infection, but basal cells survived after the viral infection and differentiated into ciliated cells. Fibroblast growth factor 10 signaling was essential for this differentiation. These results indicate that BO and BO-ALI may be used not only to evaluate the cell response to SARS-CoV-2 and coronavirus disease 2019 (COVID-19) therapeutic agents, but also for airway regeneration studies.


Subject(s)
COVID-19 , SARS-CoV-2 , Bronchi , Humans , Organoids
2.
Emerg Infect Dis ; 28(8)2022 Aug.
Article in English | MEDLINE | ID: covidwho-1902889

ABSTRACT

Household transmission is a primary source of SARS-CoV-2 spread. We used COVID-19 epidemiologic investigation data and viral genome analysis data collected in the city of Kyoto, Japan, during January 2020-June 2021 to evaluate the effects of different settings and viral strains on SARS-CoV-2 transmission. Epidemiologic investigations of 5,061 COVID-19 cases found that the most common category for close contact was within households (35.3%); this category also had the highest reverse transcription PCR positivity. The prevalent viral lineage shifted from B.1.1.214 in the third wave to the Alpha variant in the fourth wave. The proportion of secondary cases associated with households also increased from the third to fourth waves (27% vs. 29%). Among 564 contacts from 206 households, Alpha variant was significantly associated with household transmission (odds ratio 1.52, 95% CI 1.06-2.18) compared with B.1.1.214. Public health interventions targeting household contacts and specific variants could help control SARS-CoV-2 transmission.


Subject(s)
COVID-19 , SARS-CoV-2 , COVID-19/epidemiology , COVID-19/transmission , Contact Tracing , Humans , Japan/epidemiology , SARS-CoV-2/genetics
3.
Virol J ; 19(1): 24, 2022 02 03.
Article in English | MEDLINE | ID: covidwho-1770554

ABSTRACT

INTRODUCTION: In this work, six SARS-CoV-2-specific antibody assays were evaluated, namely, two pan-immunoglobulin (pan-Ig) assays [Roche Elecsys Anti-SARS-CoV-2 (named "Elecsys" in this study) and the PerkinElmer SuperFlex™ Anti-SARS-CoV-2 Ab Assay (SuperFlex_Ab)], two IgM assays [SuperFlex™ Anti-SARS-CoV-2 IgM Assay (SuperFlex_IgM) and YHLO iFlash-SARS-CoV-2 IgM (iFlash_IgM)], and two IgG assays [SuperFlex™ Anti-SARS-CoV-2 IgG Assay (SuperFlex_IgG) and iFlash-SARS-CoV-2 IgG (iFlash_IgG)]. Combination assays of SuperFlex™ (SuperFlex_any) and iFlash (iFlash_any) were also evaluated. METHODS: A total of 438 residual serum samples from 54 COVID-19 patients in the COVID-19 group and 100 samples from individuals without evidence of SARS-CoV-2 infection in the negative control group were evaluated. RESULTS: In the early stage of COVID-19 infection, within 14 days of symptom onset, the seropositive rate was lower than that of the late stage 15 days after onset (65.4% vs 99.6%). In the total period, the pan-Ig and IgG assays had higher sensitivity (90.8-95.3%) than the IgM assays (36.5-40.7%). SuperFlex_Ab and SuperFlex_any had higher sensitivity than Elecsys and SuperFlex_IgG (p < 0.05). The specificity of all the assays was 100%, except for SuperFlex_IgM (99.0%). The concordance rate between each assay was higher (96.4-100%) in the late stage than in the early stage (77.4-98.1%). CONCLUSION: For the purpose of COVID-19 diagnosis, antibody testing should be performed 15 days after onset. For the purpose of epidemiological surveillance, highly sensitive assays should be used as much as possible, such as SuperFlex_Ab, iFlash_IgG and their combination. IgM assays were not suitable for these purposes.


Subject(s)
Antibodies, Viral/analysis , COVID-19 Serological Testing/methods , COVID-19 , COVID-19/diagnosis , Humans , Immunoglobulin G/analysis , Immunoglobulin M/analysis , SARS-CoV-2/immunology , Sensitivity and Specificity
4.
Influenza Other Respir Viruses ; 16(4): 690-695, 2022 Jul.
Article in English | MEDLINE | ID: covidwho-1731169

ABSTRACT

BACKGROUND: During the third wave of the COVID-19 pandemic at the end of 2020, clusters occurred frequently in aged-care facilities (ACFs), which put pressure on the medical field in Japan. Based on this experience, Kyoto University and Kyoto City collaborated to promote a citywide COVID-19 prevention strategy to prevent the spread of COVID-19 within ACFs. The aim of this study was to clarify the effect of the prevention strategy among ACFs in Kyoto City during the third and fifth waves of the pandemic. METHODS: During the study period, the following measures were adopted as the prevention strategy in all ACFs: (1) active polymerase chain reaction (PCR) mass testing and facility-wide testing when a single case was identified, (2) implementation of strategies to prevent transmission within a facility, and (3) vaccination program for ACFs. RESULTS: Of the 1,144 facilities subjected to the mass testing, 71.0% participated in the whole program including active PCR testing. The remainder participated in the rest of the programs. The prevalence of ACF-related COVID-19 cases among total COVID-19 cases in Kyoto City decreased from 7.9% in the third wave to 4.1% in the fourth wave and 2.1% in the fifth wave. The incidence of clusters and proportion of severe elderly cases also decreased during the study period. CONCLUSIONS: A city-wide multidisciplinary effort including PCR mass testing and a vaccination program in cooperation with a university and local administrative office successfully reduced the clusters and transmission in ACFs in Kyoto City, Japan.


Subject(s)
COVID-19 , Aged , COVID-19/epidemiology , COVID-19/prevention & control , COVID-19 Testing , Clinical Laboratory Techniques , Humans , Japan/epidemiology , Pandemics/prevention & control
5.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-317688

ABSTRACT

Fifteen COVID-19 nosocomial clusters occurred in the first year of the pandemic in Kyoto City, involving 232 in-hospital patients and 157 healthcare workers (HCWs). Among them, 40 percent of index cases were HCWs. The in-hospital mortality rate among patients was 18.1%, whereas the mortality rate in the Kyoto City area during the study period was 1.79%. The time needed to contain outbreaks was shorter in hospitals with full-time infection control personnel assigned.

6.
J Clin Virol ; 136: 104760, 2021 03.
Article in English | MEDLINE | ID: covidwho-1078004

ABSTRACT

The new coronavirus infection (COVID-19) is a major public health concern, with a high burden and risk for infection among patients and healthcare workers. Saliva droplets containing SARS-COV-2 are a major vector for COVID-19 infection, making saliva a promising alternative for COVID-19 testing using nasopharyngeal swab samples. To diagnose COVID-19 patients in the field, a point-of-care test (POCT) using saliva was conceptualized. We have developed a simple method for extracting RNA from saliva samples using semi-alkaline proteinase, a sputum homogenizer typically used for preparing samples for tuberculosis testing, and a subsequent simple heating step with no need for centrifugation or RNA extraction. Further, we newly developed a triplex reverse transcription loop-mediated isothermal amplification approach (RT-LAMP) which utilizes colorimetric readout using a heat block, with results evaluated with the unaided eye. In 44 clinical patients suspected of having COVID-19 infection, the test took 45 min, and resulted in a diagnostic sensitivity of 82.6% (19/23) and diagnostic specificity of 100% (21/21), compared to the reference standard. The limit of detection was 250 copies/reaction (25,000 copies/mL). Our newly developed POCT approach achieved simple RNA extraction and constant RT-LAMP detection. This POCT has the potential to be used for simple inspection stations in a field setting, helping reduce the risk of infection by simplifying and accelerating testing for COVID-19.


Subject(s)
COVID-19 Nucleic Acid Testing/methods , COVID-19/diagnosis , Point-of-Care Testing , RNA, Viral/analysis , Saliva/virology , Humans , Limit of Detection , Molecular Diagnostic Techniques/methods , Nucleic Acid Amplification Techniques/methods , SARS-CoV-2/genetics , SARS-CoV-2/isolation & purification
7.
J Mol Diagn ; 23(2): 164-170, 2021 02.
Article in English | MEDLINE | ID: covidwho-1065362

ABSTRACT

Molecular testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the mainstay for accurate diagnosis of the infection, but the diagnostic performances of available assays have not been defined. We compared 12 molecular diagnostic assays, including 8 commercial kits using 155 respiratory samples (65 nasopharyngeal swabs, 45 oropharyngeal swabs, and 45 sputum) collected at two Japanese hospitals. Sixty-eight samples were positive for more than one assay and one genetic locus, and were defined as true-positive samples. All the assays showed a specificity of 100% (95% CI, 95.8%-100%). The N2 assay kit of the US Centers for Disease Control and Prevention and the N2 assay of the Japanese National Institute of Infectious Disease (NIID) were the most sensitive assays with 100% sensitivity (95% CI, 94.7-100), followed by the Centers for Disease Control and Prevention N1 kit, E assay by Corman, and Japanese National Institute of Infectious Disease N2 assay multiplex with internal control reactions. These assays are reliable as first-line molecular assays in laboratories when combined with appropriate internal control reactions.


Subject(s)
COVID-19 Testing , COVID-19/diagnosis , Molecular Diagnostic Techniques , SARS-CoV-2/genetics , SARS-CoV-2/isolation & purification , COVID-19/virology , Humans , Sensitivity and Specificity
8.
J Mol Diagn ; 23(2): 164-170, 2021 02.
Article in English | MEDLINE | ID: covidwho-977141

ABSTRACT

Molecular testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the mainstay for accurate diagnosis of the infection, but the diagnostic performances of available assays have not been defined. We compared 12 molecular diagnostic assays, including 8 commercial kits using 155 respiratory samples (65 nasopharyngeal swabs, 45 oropharyngeal swabs, and 45 sputum) collected at two Japanese hospitals. Sixty-eight samples were positive for more than one assay and one genetic locus, and were defined as true-positive samples. All the assays showed a specificity of 100% (95% CI, 95.8%-100%). The N2 assay kit of the US Centers for Disease Control and Prevention and the N2 assay of the Japanese National Institute of Infectious Disease (NIID) were the most sensitive assays with 100% sensitivity (95% CI, 94.7-100), followed by the Centers for Disease Control and Prevention N1 kit, E assay by Corman, and Japanese National Institute of Infectious Disease N2 assay multiplex with internal control reactions. These assays are reliable as first-line molecular assays in laboratories when combined with appropriate internal control reactions.


Subject(s)
COVID-19 Testing , COVID-19/diagnosis , Molecular Diagnostic Techniques , SARS-CoV-2/genetics , SARS-CoV-2/isolation & purification , COVID-19/virology , Humans , Sensitivity and Specificity
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