You are presented with a paragraph from a COVID-19 literature. Classify the topics of this piece of text by choosing from the following categories:

- Epidemic Forecasting: The content relates to predictions about the spread of COVID-19.
- Treatment: The paragraph discusses therapeutic methods or medication for COVID-19.
- Prevention: The content covers measures to prevent the spread of COVID-19.
- Mechanism: The paragraph explains the biological mechanisms of the virus.
- Case Report: The content is a report of a COVID-19 case.
- Transmission: The paragraph discusses how COVID-19 is transmitted.
- Diagnosis: The content is about diagnosing COVID-19 in individuals.

Your classification should be provided as an element within a JSON array. The array should be formatted with topics enclosed in double quotes and separated by commas, following the JSON format, for example: ["Topic1", "Topic2", ...]. Include all applicable topics within the array. Your output should be a valid JSON array, and no additional text should be included in your response.

Article:

BACKGROUND: We wanted to better understand the frequency and temporal distribution of symptoms of COVID-19 in very old patients, which are currently not well defined. METHODS: In an observational, descriptive study, we followed all patients being at three geriatric convalescence and rehabilitation units when a COVID-19 outbreak emerged in those units in March 2020. For those who developed the disease, we recorded any new symptom occurring at diagnosis, in the previous 14 and the following 21 days. A group of SARS-Cov-2-negative patients served as controls. RESULTS: Sixty-nine of the 176 inpatients (mean age: 86 years) were infected by SARS-Cov-2 during the outbreak. At the moment of diagnosis, a majority of patients had fever (71.0%), malaise-asthenia (24.6%), or respiratory symptoms (66.7%). However, 48 patients (69.6% of all SARS-Cov-2 positive patients) also presented, usually several days before, other symptoms: (a) gastrointestinal symptoms (39.1% of all patients, median onset eight days before diagnosis, IQR -9 to +3 days); (b) neurological symptoms (30.4% of all patients, median onset five days before diagnosis, IQR -11 to -3 days), notably delirium (24.6%); and (c) other symptoms, like falls and unexplained decompensation of chronic conditions (29.0% of all patients, median onset four days before diagnosis, IQR -10 to 0). None of those symptoms were observed in similar proportion in 25 control SARS-CoV-2-negative patients, hospitalized during the same period. CONCLUSIONS: Diarrhea, nausea-vomiting, delirium, falls, and unexplained decompensation of chronic conditions were the first symptoms of COVID-19 in a majority of older patients in this cohort, preceding typical symptoms by several days. Recognizing those early symptoms could hasten the diagnosis of COVID-19 in this population.
["Diagnosis"]