Objective: Coronavirus disease 2019 (COVID-19) has spread worldwide, including Japan. However, little is known about the clinical symptoms which discriminate between COVID-19 and non-COVID-19 among outpatients in general practitioner clinics, which is important for efficient case detection. The aim of this study was to investigate the clinical symptoms to discriminate between COVID-19 and non-COVID-19 cases among outpatients in general practitioner clinics during the second wave of the COVID-19 pandemic in Japan in August 2020. Methods: The records of 360 patients who visited a clinic with suspicion of infectious disease and underwent COVID-19 PCR test between 1 and 14 August 2020 were used. The patients filled out a questionnaire on possible clinical symptoms and transmission routes. Multivariate logistic regression was used to investigate the association between clinical symptoms and COVID-19 status. Results: COVID-19-positive patients were 17 (4.7%). Multiple logistic regression analyses showed that anosmia (odds ratio (OR), 25.94 95% confidence interval (CI), 7.15–94.14; p < 0.001), headache (OR, 3.31 95% confidence interval (CI), 0.98–11.20; p = 0.054), sputum production (OR, 3.32 CI, 1.01–10.90; p = 0.048) and history of visiting an izakaya or bar (OR, 4.23 CI, 0.99–18.03; p = 0.051) were marginally significantly associated withbeing COVID-19 positive. This model showed moderate predictive power (area under receiver operating characteristic curve = 0.870 CI, 0.761 to 0.971). Conclusions: We found that anosmia, headache, sputum production, history of visiting an izakaya or bar were associated with COVID-19, which can be used to detect patients with COVID-19 in out-patient clinics in Japan. The findings of this study need to be verified in other clinics and hospitals in Japan and other countries with universal healthcare coverages.

The clinical characteristics of patients with N501Y mutation in SARS-CoV-2 variants (N501YV) is not fully understood, especially in the setting of general practice. In this retrospective cohort study, COVID-19 patients admitted to one general practitioner clinic between 26 March and 26 May 2021 were retrospectively analyzed. The characteristics, clinical symptoms and radiological findings before treatment were compared between N501YV and wild-type 501N. Twenty-eight patients were classified as wild-type 501N and 24 as N501YV. The mean (±standard deviation) age was 37.4 (±16.1) years, with no significant difference between groups. Among clinical symptoms, prevalence of fever of 38 degrees Celsius (°C) or higher was significantly higher in the N501YV group than in the wild-type 501N group (p = 0.001). Multivariate analysis showed that fever of 38 °C or higher remained significantly associated with N501YV (adjust odds ratio [aOR]: 6.07, 95% confidence interval [CI]: 1.68 to 21.94). For radiological findings, the lung involvement area was significantly larger in patients infected with N501YV (p = 0.013). In conclusion, in the N501YV group, fever of 38 °C or higher and extensive pneumonia were more frequently observed compared to the wild-type 501N group. There was no significant difference in terms of other demographics and clinical symptoms.