Nasopharyngeal and oropharyngeal swab and sputum samples were collected from symptomatic patients to detect SARS-CoV-2 by real-time reverse transcriptase (RT)-PCR. RNA was extracted from clinical samples with a QIAamp viral RNA mini kit (QIAGEN, Hilden, Germany) following the manufacturer’s instructions. All specimens were handled under a biosafety cabinet according to laboratory biosafety guidelines of Korea Centers for Disease Control and Prevention for COVID-19.