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:

One year after the outbreak of coronavirus disease 2019 (COVID-19), referrals for persistent headache, often defined as "post-COVID headache," have become increasingly common in outpatient headache clinics. However, it is important to take into consideration that this term may include a spectrum of clinically different headache types. We describe three cases of migraine-like headaches in individuals with a history of mild COVID-19 infection to demonstrate some of the different phenotypes of persistent headaches seen. These cases highlight the importance of a careful evaluation when assessing the complexities of "post-COVID headache" as well as the need to further investigate the different, underlying, pathophysiological mechanisms.
["Case Report"]