Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 4 de 4
Filter
1.
Epidemiologia ; 2(1):75-83, 2021.
Article | WHO COVID | ID: covidwho-1125928

ABSTRACT

We begin with a simple model for the COVID-19 epidemic and add face mask usages and testing and quarantine of infectives We estimate the effect on the reproduction number and discuss the question of whether the epidemic can be controlled by increased use of face masks

2.
Epidemics ; 34: 100439, 2021 03.
Article in English | MEDLINE | ID: covidwho-1068904

ABSTRACT

Epidemiological models are widely used to analyze the spread of diseases such as the global COVID-19 pandemic caused by SARS-CoV-2. However, all models are based on simplifying assumptions and often on sparse data. This limits the reliability of parameter estimates and predictions. In this manuscript, we demonstrate the relevance of these limitations and the pitfalls associated with the use of overly simplistic models. We considered the data for the early phase of the COVID-19 outbreak in Wuhan, China, as an example, and perform parameter estimation, uncertainty analysis and model selection for a range of established epidemiological models. Amongst others, we employ Markov chain Monte Carlo sampling, parameter and prediction profile calculation algorithms. Our results show that parameter estimates and predictions obtained for several established models on the basis of reported case numbers can be subject to substantial uncertainty. More importantly, estimates were often unrealistic and the confidence/credibility intervals did not cover plausible values of critical parameters obtained using different approaches. These findings suggest, amongst others, that standard compartmental models can be overly simplistic and that the reported case numbers provide often insufficient information for obtaining reliable and realistic parameter values, and for forecasting the evolution of epidemics.


Subject(s)
/epidemiology , Models, Statistical , Pandemics , Algorithms , China/epidemiology , Forecasting , Humans , Markov Chains , Monte Carlo Method , Reproducibility of Results , Uncertainty
3.
Nat Immunol ; 21(9): 1107-1118, 2020 09.
Article in English | MEDLINE | ID: covidwho-710376

ABSTRACT

In coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, the relationship between disease severity and the host immune response is not fully understood. Here we performed single-cell RNA sequencing in peripheral blood samples of 5 healthy donors and 13 patients with COVID-19, including moderate, severe and convalescent cases. Through determining the transcriptional profiles of immune cells, coupled with assembled T cell receptor and B cell receptor sequences, we analyzed the functional properties of immune cells. Most cell types in patients with COVID-19 showed a strong interferon-α response and an overall acute inflammatory response. Moreover, intensive expansion of highly cytotoxic effector T cell subsets, such as CD4+ effector-GNLY (granulysin), CD8+ effector-GNLY and NKT CD160, was associated with convalescence in moderate patients. In severe patients, the immune landscape featured a deranged interferon response, profound immune exhaustion with skewed T cell receptor repertoire and broad T cell expansion. These findings illustrate the dynamic nature of immune responses during disease progression.


Subject(s)
Antigens, CD/metabolism , Antigens, Differentiation, T-Lymphocyte/metabolism , Betacoronavirus/immunology , Coronavirus Infections/immunology , Interferon Type I/metabolism , Pneumonia, Viral/immunology , Receptors, Immunologic/metabolism , Adolescent , Adult , Aged , Antigens, CD/genetics , Antigens, CD/immunology , Antigens, Differentiation, T-Lymphocyte/genetics , Antigens, Differentiation, T-Lymphocyte/immunology , CD4-Positive T-Lymphocytes/immunology , CD4-Positive T-Lymphocytes/metabolism , CD8-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/metabolism , Cohort Studies , Coronavirus Infections/blood , Coronavirus Infections/diagnosis , Coronavirus Infections/virology , Female , GPI-Linked Proteins/genetics , GPI-Linked Proteins/immunology , GPI-Linked Proteins/metabolism , Humans , Interferon Type I/genetics , Interferon Type I/immunology , Killer Cells, Natural/immunology , Killer Cells, Natural/metabolism , Male , Middle Aged , Pandemics , Pneumonia, Viral/blood , Pneumonia, Viral/diagnosis , Pneumonia, Viral/virology , RNA-Seq , Receptors, Immunologic/genetics , Receptors, Immunologic/immunology , Severity of Illness Index , Single-Cell Analysis
4.
Acta Pharm Sin B ; 10(7): 1205-1215, 2020 Jul.
Article in English | MEDLINE | ID: covidwho-88716

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can cause acute respiratory distress syndrome, hypercoagulability, hypertension, and multiorgan dysfunction. Effective antivirals with safe clinical profile are urgently needed to improve the overall prognosis. In an analysis of a randomly collected cohort of 124 patients with COVID-19, we found that hypercoagulability as indicated by elevated concentrations of D-dimers was associated with disease severity. By virtual screening of a U.S. FDA approved drug library, we identified an anticoagulation agent dipyridamole (DIP) in silico, which suppressed SARS-CoV-2 replication in vitro. In a proof-of-concept trial involving 31 patients with COVID-19, DIP supplementation was associated with significantly decreased concentrations of D-dimers (P < 0.05), increased lymphocyte and platelet recovery in the circulation, and markedly improved clinical outcomes in comparison to the control patients. In particular, all 8 of the DIP-treated severely ill patients showed remarkable improvement: 7 patients (87.5%) achieved clinical cure and were discharged from the hospitals while the remaining 1 patient (12.5%) was in clinical remission.

SELECTION OF CITATIONS
SEARCH DETAIL