2.2.2. General Characteristics of the Subjects and their Symptoms before Release from Quarantine

The general characteristics of the selected subjects included sex, age, underlying disease (past history), and drug use. Information related to COVID-19 included the dates of confirmation, hospitalization, and discharge, the status of hospitalization (inpatient facility or medical institution), and any period in an ICU. For those released from self-quarantine without having to be admitted to a medical institution, the date of diagnosis and the date of release from quarantine were recorded. Moreover, the primary clinical symptoms experienced during the 7 days prior to diagnosis were noted. Clinical symptoms included fever, cough, excess sputum, sore throat, rhinorrhea, nasal congestion, dysosmia, anosmia, dysgeusia, pressure or discomfort in the chest, dyspnea, myalgia, headache, fatigue and malaise, diarrhea, and abdominal discomfort. Asymptomatic cases were also recorded.

#### 2.2.3. Evaluation of Physical Condition after Release from Quarantine

To evaluate the physical condition of patients released from quarantine, symptoms suggestive of recurrence were verified such as shortness of breath, a clinically possible sequela, cough, olfactory abnormality, and headache. Moreover, patients were asked to rate their general physical condition after release from quarantine using a five-point Likert scale: "much better", "slightly better", "similar", "slightly worse", and "much worse".

#### 2.2.4. Evaluation of Psychological Status after Release from Quarantine

Psychological status after release from quarantine was verified with respect to anxiety, depression, insomnia, and mental stress. For anxiety and depression, questions to which responses were given on a four-point Likert scale: "never", "rarely", "sometimes", and "often". The criterion for "never" was the absence of any of the above symptoms. "Rarely" to "often" meant that symptoms affected daily life. Insomnia was rated on a three-point Likert scale: "never", "sometimes", and "often"; "often" means that it occurs so often that it affects daily life. Response to stress was rated on a five-point Likert scale: "never", "very rarely", "sometimes", "often", and "very often".
