Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 5 de 5
Filter
1.
J Med Virol ; 94(1): 147-153, 2022 01.
Article in English | MEDLINE | ID: covidwho-1363704

ABSTRACT

This study aimed to determine the frequency of SARS-CoV-2 RNA in serum and its association with the clinical severity of COVID-19. This retrospective cohort study performed at Toyama University Hospital included consecutive patients with confirmed COVID-19. The prevalence of SARS-CoV-2 RNAemia and the strength of its association with clinical severity variables were examined. Fifty-six patients were included in this study. RNAemia was detected in 19.6% (11/56) patients on admission, and subsequently in 1.0% (1/25), 50.0% (6/12), and 100.0% (4/4) moderate, severe, and critically ill patients, respectively. Patients with RNAemia required more frequent oxygen supplementation (90.0% vs. 13.3%), ICU admission (81.8% vs. 6.7%), and invasive mechanical ventilation (27.3% vs. 0.0%). Among patients with RNAemia, the median viral loads of nasopharyngeal (NP) swabs that were collected around the same time as the serum sample were significantly higher in critically ill (5.4 log10 copies/µl; interquartile range [IQR]: 4.2-6.3) than in moderate-severe cases (2.6 log10 copies/µl; [IQR: 1.1-4.5]; p = 0.030) and were significantly higher in nonsurvivors (6.2 log10 copies/µl [IQR: 6.0-6.5]) than in survivors (3.9 log10 copies/µl [IQR: 1.6-4.6]; p = 0.045). This study demonstrated a relatively high proportion of SARS-CoV-2 RNAemia and an association between RNAemia and clinical severity. Moreover, among the patients with RNAemia, the viral loads of NP swabs were correlated with disease severity and mortality, suggesting the potential utility of combining serum testing with NP tests as a prognostic indicator for COVID-19, with higher quality than each separate test.


Subject(s)
COVID-19/virology , Nasopharynx/virology , RNA, Viral/blood , SARS-CoV-2/isolation & purification , Viral Load , Viremia , Adolescent , Adult , Aged , COVID-19/mortality , COVID-19/physiopathology , Child , Critical Illness , Female , Humans , Male , Middle Aged , Prognosis , Retrospective Studies , Severity of Illness Index , Young Adult
2.
Sci Rep ; 11(1): 16535, 2021 08 16.
Article in English | MEDLINE | ID: covidwho-1360210

ABSTRACT

Adaptive immunity to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) dynamics remain largely unknown. The neutralizing antibody (NAb) levels in patients with coronavirus disease 2019 (COVID-19) are helpful for understanding the pathology. Using SARS-CoV-2 pseudotyped virus, serum sample neutralization values in symptomatic COVID-19 patients were measured using the chemiluminescence reduction neutralization test (CRNT). At least two sequential serum samples collected during hospitalization were analyzed to assess NAbs neutralizing activity dynamics at different time points. Of the 11 patients, four (36.4%), six (54.5%), and one (9.1%) had moderate, severe, and critical disease, respectively. Fifty percent neutralization (N50%-CRNT) was observed upon admission in 90.9% (10/11); all patients acquired neutralizing activity 2-12 days after onset. In patients with moderate disease, neutralization was observed at earliest within two days after symptom onset. In patients with severe-to-critical disease, neutralization activity increased, plateauing 9-16 days after onset. Neutralization activity on admission was significantly higher in patients with moderate disease than in patients with severe-to-critical disease (relative % of infectivity, 6.4% vs. 41.1%; P = .011). Neutralization activity on admission inversely correlated with disease severity. The rapid NAb response may play a crucial role in preventing the progression of COVID-19.


Subject(s)
Adaptive Immunity , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , COVID-19/diagnosis , SARS-CoV-2/immunology , Aged , Aged, 80 and over , Antibodies, Viral/immunology , COVID-19/blood , COVID-19/immunology , COVID-19/virology , COVID-19 Nucleic Acid Testing , Disease Progression , Female , Humans , Male , Middle Aged , Neutralization Tests/statistics & numerical data , Retrospective Studies , SARS-CoV-2/genetics , SARS-CoV-2/isolation & purification , Severity of Illness Index , Time Factors
3.
Virol J ; 18(1): 16, 2021 01 12.
Article in English | MEDLINE | ID: covidwho-1059645

ABSTRACT

BACKGROUND: SARS-CoV-2 is a novel coronavirus that emerged in 2019 and is now classified in the genus Coronavirus with closely related SARS-CoV. SARS-CoV-2 is highly pathogenic in humans and is classified as a biosafety level (BSL)-3 pathogen, which makes manipulating it relatively difficult due to its infectious nature. METHODS: To circumvent the need for BSL-3 laboratories, an alternative assay was developed that avoids live virus and instead uses a recombinant VSV expressing luciferase and possesses the full length or truncated spike proteins of SARS-CoV-2. Furthermore, to measure SARS-CoV-2 neutralizing antibodies under BSL2 conditions, a chemiluminescence reduction neutralization test (CRNT) for SARS-CoV-2 was developed. The neutralization values of the serum samples collected from hospitalized patients with COVID-19 or SARS-CoV-2 PCR-negative donors against the pseudotyped virus infection evaluated by the CRNT were compared with antibody titers determined from an enzyme-linked immunosorbent assay (ELISA) or an immunofluorescence assay (IFA). RESULTS: The CRNT, which used whole blood collected from hospitalized patients with COVID-19, was also examined. As a result, the inhibition of pseudotyped virus infection was specifically observed in both serum and whole blood and was also correlated with the results of the IFA. CONCLUSIONS: In conclusion, the CRNT for COVID-19 is a convenient assay system that can be performed in a BSL-2 laboratory with high specificity and sensitivity for evaluating the occurrence of neutralizing antibodies against SARS-CoV-2.


Subject(s)
Antibodies, Neutralizing/blood , COVID-19 Serological Testing/methods , COVID-19/blood , Neutralization Tests/methods , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Vesicular stomatitis Indiana virus/genetics , Animals , Antibodies, Neutralizing/immunology , Antibodies, Viral/blood , Antibodies, Viral/immunology , COVID-19/immunology , Cell Line , Convalescence , Humans , Inhibitory Concentration 50 , Luminescence , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics
4.
Virol J ; 18(1): 16, 2021 01 12.
Article in English | MEDLINE | ID: covidwho-1024369

ABSTRACT

BACKGROUND: SARS-CoV-2 is a novel coronavirus that emerged in 2019 and is now classified in the genus Coronavirus with closely related SARS-CoV. SARS-CoV-2 is highly pathogenic in humans and is classified as a biosafety level (BSL)-3 pathogen, which makes manipulating it relatively difficult due to its infectious nature. METHODS: To circumvent the need for BSL-3 laboratories, an alternative assay was developed that avoids live virus and instead uses a recombinant VSV expressing luciferase and possesses the full length or truncated spike proteins of SARS-CoV-2. Furthermore, to measure SARS-CoV-2 neutralizing antibodies under BSL2 conditions, a chemiluminescence reduction neutralization test (CRNT) for SARS-CoV-2 was developed. The neutralization values of the serum samples collected from hospitalized patients with COVID-19 or SARS-CoV-2 PCR-negative donors against the pseudotyped virus infection evaluated by the CRNT were compared with antibody titers determined from an enzyme-linked immunosorbent assay (ELISA) or an immunofluorescence assay (IFA). RESULTS: The CRNT, which used whole blood collected from hospitalized patients with COVID-19, was also examined. As a result, the inhibition of pseudotyped virus infection was specifically observed in both serum and whole blood and was also correlated with the results of the IFA. CONCLUSIONS: In conclusion, the CRNT for COVID-19 is a convenient assay system that can be performed in a BSL-2 laboratory with high specificity and sensitivity for evaluating the occurrence of neutralizing antibodies against SARS-CoV-2.


Subject(s)
Antibodies, Neutralizing/blood , COVID-19 Serological Testing/methods , COVID-19/blood , Neutralization Tests/methods , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Vesicular stomatitis Indiana virus/genetics , Animals , Antibodies, Neutralizing/immunology , Antibodies, Viral/blood , Antibodies, Viral/immunology , COVID-19/immunology , Cell Line , Convalescence , Humans , Inhibitory Concentration 50 , Luminescence , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics
5.
PLoS One ; 15(12): e0243597, 2020.
Article in English | MEDLINE | ID: covidwho-967413

ABSTRACT

OBJECTIVE: To investigate the relationship between viral load and secondary transmission in novel coronavirus disease 2019 (COVID-19). METHODS: Epidemiological and clinical data were obtained from immunocompetent laboratory-confirmed patients with COVID-19 who were admitted to and/or from whom viral loads were measured at Toyama University Hospital. Using a case-control approach, index patients who transmitted the disease to at least one other patient were analysed as "cases" (index patients) compared with patients who were not the cause of secondary transmission (non-index patients, analysed as "controls"). The viral load time courses were assessed between the index and non-index symptomatic patients using non-linear regression employing a standard one-phase decay model. RESULTS: In total, 28 patients were included in the analysis. Median viral load at the initial sample collection was significantly higher in symptomatic than in asymptomatic patients and in adults than in children. Among symptomatic patients (n = 18), non-linear regression models showed that the estimated viral load at onset was higher in the index than in the non-index patients (median [95% confidence interval]: 6.6 [5.2-8.2] vs. 3.1 [1.5-4.8] log copies/µL, respectively). In adult (symptomatic and asymptomatic) patients (n = 21), median viral load at the initial sample collection was significantly higher in the index than in the non-index patients (p = 0.015, 3.3 vs. 1.8 log copies/µL, respectively). CONCLUSIONS: High nasopharyngeal viral loads around onset may contribute to secondary transmission of COVID-19. Viral load may help provide a better understanding of why transmission is observed in some instances, but not in others, especially among household contacts.


Subject(s)
COVID-19 , Models, Biological , Nasopharynx , SARS-CoV-2/metabolism , Viral Load , Adolescent , Adult , Aged , COVID-19/metabolism , COVID-19/transmission , Case-Control Studies , Child , Child, Preschool , Female , Humans , Infant , Infant, Newborn , Male , Middle Aged , Nasopharynx/metabolism , Nasopharynx/virology
SELECTION OF CITATIONS
SEARCH DETAIL
...