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:

Aim: COVID-19, caused by SARS-CoV-2, started in December 2019 and has spread across the world. Materials & methods: We analyzed real-time PCR results of 10,000 samples from 2 April to 30 May 2020 in three neighbor cities located in the East of Turkey. The final study population was 7853 cases, after excluding screening tests. Results: Real-time PCR was performed to detect the SARS-CoV-2-specific RNA-dependent-RNA-polymerase gene fragment. The number of total positive samples out of 7853 were 487; however, the number of nonrepeating positive patient was 373 (4.8%). Cough and fever were the most common symptoms in positive cases. Conclusion: Epidemiologic studies should be performed about the prevalence of SARS-CoV-2 infection to better understand the effect of the virus across the world.
["Diagnosis"]