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1.
Sci Rep ; 11(1): 16535, 2021 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-34400739

RESUMO

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.


Assuntos
Imunidade Adaptativa , Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , COVID-19/diagnóstico , SARS-CoV-2/imunologia , Idoso , Idoso de 80 Anos ou mais , Anticorpos Antivirais/imunologia , COVID-19/sangue , COVID-19/imunologia , COVID-19/virologia , Teste de Ácido Nucleico para COVID-19 , Progressão da Doença , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Testes de Neutralização/estatística & dados numéricos , Estudos Retrospectivos , SARS-CoV-2/genética , SARS-CoV-2/isolamento & purificação , Índice de Gravidade de Doença , Fatores de Tempo
2.
J Med Virol ; 2021 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-34411312

RESUMO

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.

3.
J Infect Chemother ; 27(7): 1122-1125, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33853730

RESUMO

This study aimed to assess the nasopharyngeal viral load at discharge or time of discontinued isolation in coronavirus 2019 (COVID-19) patients admitted to our hospital and discharged under the current symptom-based criteria in Japan. Patients diagnosed with COVID-19 by reverse transcription polymerase chain reaction and hospitalized at Toyama University Hospital were included in the analysis. Nasopharyngeal viral load was measured when symptom-based criteria for discharge or end of isolation in the accommodations were met, and examined the relationship between viral load and days after onset or age. From the perspective of virus isolation limit, the amount of infectious viral load was defined at 50 copies/µL by nasopharyngeal sample. Thirty-three patients with laboratory-confirmed COVID-19 were included in the analysis, after excluding critical and fatal cases. Mean nasopharyngeal viral load at discharge or end of isolation was 1.90 log-copies/µL, and 64% of patients were discharged with over 50 copies/µL. No correlation was apparent between age and viral load at discharge, and viral load remained relatively high at discharge or end of isolation in all age groups. Although attempts at infectious virus isolation are necessary, infection control precautions even after discharge or discontinued isolation in accommodations may be needed, as the date of onset mostly depended on self-reporting by patients.


Assuntos
COVID-19 , Alta do Paciente , Humanos , Japão , SARS-CoV-2 , Carga Viral
4.
Int J Infect Dis ; 106: 33-35, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33746092

RESUMO

As of October 2020, there is still no specific drug to treat COVID-19 as it rages worldwide. Favipiravir, indicated for the treatment of new and re-emerging influenza infections, has been suggested to be effective against SARS-CoV-2, although this is not yet fully validated. We administered favipiravir to a 64-year-old female patient with COVID-19. Her symptoms resolved quickly after the start of treatment, with reduction of SARS-CoV-2 viral load, but she developed a fever again on day 12. Since the fever was relieved by discontinuation of favipiravir, and based on positive results with a drug-induced lymphocyte stimulation test, we diagnosed her with favipiravir-induced drug fever. A decrease in the serum concentration of favipiravir was observed along with resolution of the fever. The present case suggests that drug fever should be considered in the differential diagnosis of relapsing fever episodes in COVID-19 patients receiving favipiravir.


Assuntos
Amidas/efeitos adversos , COVID-19/tratamento farmacológico , COVID-19/imunologia , Febre/induzido quimicamente , Ativação Linfocitária/efeitos dos fármacos , Pirazinas/efeitos adversos , Amidas/farmacologia , Amidas/uso terapêutico , COVID-19/diagnóstico , Feminino , Humanos , Pessoa de Meia-Idade , Pirazinas/farmacologia , Pirazinas/uso terapêutico , Carga Viral/efeitos dos fármacos
5.
PLoS One ; 15(12): e0243597, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33296437

RESUMO

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.


Assuntos
COVID-19 , Modelos Biológicos , Nasofaringe , SARS-CoV-2/metabolismo , Carga Viral , Adolescente , Adulto , Idoso , COVID-19/metabolismo , COVID-19/transmissão , Estudos de Casos e Controles , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Nasofaringe/metabolismo , Nasofaringe/virologia
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