However, we thought that even a small number of patients with persistent positive RT-PCR test for COVID-19 could be helpful in the clinical interpretation of COVID-19 test results if we could identify the tendencies of these patients.In previous studies, it was reported that COVID-19 patients with mild symptoms, older patients, or patients with elevated SARS-CoV-2-specific CD8 T-cell immune responses were more likely to get persistently positive results for COVID-19 test [14, 15]. The gene discussed is CD8A; the disease is COVID-19.