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:

Coronavirus disease 2019 (COVID-19) is a contagious disease caused by severe acute respiratory syndrome coronavirus-2. Patients with hematologic malignancies have been shown to have higher risk of mortality due to COVID-19 than reported in the general adult population. Reports on acute lymphoblastic leukemia and COVID in children are scarce. We present a case of an 11-year-old male patient undergoing treatment for B-cell acute lymphoblastic leukemia with an atypical course of COVID-19. The patient received a positive result of the syndrome coronavirus-2 polymerase chain reaction test performed due to epidemiologic reasons. The chemotherapy was continued since the patient had no clinical signs of COVID-19. The disease started with intensive gastrointestinal bleeding, followed by severe respiratory tract infection over 2 weeks later.
["Case Report"]