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:

OBJECTIVE: Currently, coronavirus disease 2019 (COVID-19) has spread worldwide and become a global health concern. Here, we report a familial cluster of six patients infected with severe acute respiratory coronavirus 2 (SARS-CoV-2) in a northern Chinese region and share our local experience with regard the control of COVID-19. METHODS: The demographic data, clinical features, laboratory examinations, and epidemiological characteristics of enrolled cases were collected and analyzed. Two family members (Cases 1 and 2) had Hubei exposure history and were admitted to the hospital with a confirmed diagnosis of COVID-19; eight familial members who had contact with them during the incubation period underwent quarantine in a hospital. We closely followed up all the family members and analyzed their clinical outcome. RESULTS: Case 3 had negative SARS-CoV-2 reverse transcription-polymerase chain reaction (RT-PCR) results but was suspected to have COVID-19 because of radiographic abnormalities. Cases 4 and 5 developed symptomatic COVID-19. Case 6 was considered an asymptomatic carrier as his SARS-CoV-2 RT-PCR result was positive. The other four family members with close contacts to COVID-19 patients had no evidence of SARS-CoV-2 infection. CONCLUSIONS: Our findings suggest that COVID-19 has infectivity during the incubation period and preventive quarantine is effective for controlling an outbreak of COVID-19 infection.
["Case Report"]