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: Several gastroenterology societies have created recommendations in order to reduce nonessential exposure to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. Our aim is to evaluate the national gastroenterologists' perspective on the impact of COVID-19 and the impact of reorganization of a gastroenterology department during the COVID-19 pandemic. Methods: For the first purpose, an online survey was distributed to gastroenterologists nationwide. For the second purpose, the authors conducted an analysis of some endoscopic procedures performed at the Gastroenterology Department of the Centro Hospitalar Vila Nova de Gaia/Espinho (CHVNG/E) between March 16 and May 8 during the years 2019 and 2020. Results: Sixty-seven gastroenterologists answered our survey. Only 14.9% were residents and 86.6% worked in a hospital with COVID-19 patients, with 16.4% assigned to assist those patients. All of the departments suffered modifications. Ninety percent of the residents affirmed that their activity had changed. Ninety-four percent declared having nonessential endoscopic procedures postponed, and 85.1% maintained in-person medical visits, 88.1% were already having remote consultations, and 11.9% did not have any clinical visit. In our gastroenterology unit, the number of endoscopic procedures decreased by 73.1% from 2019 to 2020. In 2020, the proportion of urgent procedures was higher compared to 2019. Conclusion: The advent of COVID-19 has led to important changes in gastroenterology activities in Portugal, and national gastroenterology units are complying with the recommendations. Furthermore, Portuguese gastroenterologists believed that the decrease in endoscopic activity can compromise residents' education and training. The gastroenterology department at CHVNG/E has shown a significant reduction in the number of endoscopic procedures.
["Prevention"]