Time series analysis of the incidence of acute upper respiratory tract infections, COVID-19 and the use of antibiotics in Finland during the COVID-19 epidemic: a cohort study of 833 444 patients.

OBJECTIVE: To evaluate the trajectories of acute upper respiratory tract infections (URTIs), COVID-19, and the use of antibiotics in Finland during the COVID-19 epidemic. DESIGN: Population-based cohort study. SETTING: Electronic medical records from a nationwide healthcare chain in Finland. PARTICIPANTS: 833 444 patients from a cohort of 1 970 013 Finns who had used medical services between 2017 and 2020. MAIN OUTCOME MEASURES: Number of weekly patients of acute URTIs, COVID-19, and the prescribed number of antibiotics in Finland between 6 January 2020 and 21 June 2020. We estimated the respective expected numbers from 1 March 2020 onward using autoregressive integrated moving average model from 1 January 2017 to 1 March 2020. We assessed the public interest in COVID-19 by collecting Google search trend frequencies. RESULTS: There was a rapid increase in COVID-related internet searches between weeks 10 and 12. At the same time, there was a 106% increase in diagnoses of acute URTIs, from 410 per 100 000 inhabitants to 845 per 100 000. The first COVID-19 cases were diagnosed on week 11. Prescriptions for URTI-related antibiotics declined by 71% (403 per 100 000 to 117 per 100 000) between weeks 11 and 15 while no relevant change took place in prescriptions of antibiotics for urinary tract infections. CONCLUSIONS: At the beginning of the epidemic, many people contacted healthcare professionals with relatively mild symptoms, as indicated by the reduced rate of URTI-antibiotics prescriptions. Our findings indicate that health service providers should be prepared for rapid variations in service demand. Securing access of true COVID-19 patients to proper diagnostics, care and isolation measures may help in preventing the spread of the disease.

Differentiation of Human Pluripotent Stem Cells Into Definitive Endoderm Cells in Various Flexible Three-Dimensional Cell Culture Systems: Possibilities and Limitations.

The generation of human stem cell-derived spheroids and organoids represents a major step in solving numerous medical, pharmacological, and biological challenges. Due to the advantages of three-dimensional (3D) cell culture systems and the diverse applications of human pluripotent stem cell (iPSC)-derived definitive endoderm (DE), we studied the influence of spheroid size and 3D cell culture systems on spheroid morphology and the effectiveness of DE differentiation as assessed by quantitative PCR (qPCR), flow cytometry, immunofluorescence, and computational modeling. Among the tested hydrogel-based 3D systems, we found that basement membrane extract (BME) hydrogel could not retain spheroid morphology due to dominant cell-matrix interactions. On the other hand, we found that nanofibrillar cellulose (NFC) hydrogel could maintain spheroid morphology but impeded growth factor diffusion, thereby negatively affecting cell differentiation. In contrast, suspension culture provided sufficient mass transfer and was demonstrated by protein expression assays, morphological analyses, and mathematical modeling to be superior to the hydrogel-based systems. In addition, we found that spheroid size was reversely correlated with the effectiveness of DE formation. However, spheroids of insufficient sizes failed to retain 3D morphology during differentiation in all the studied culture conditions. We hereby demonstrate how the properties of a chosen biomaterial influence the differentiation process and the importance of spheroid size control for successful human iPSC differentiation. Our study provides critical parametric information for the generation of human DE-derived, tissue-specific organoids in future studies.