Clinical characteristics of the recovered COVID-19 patients with re-detectable positive RNA test

Jianghong An; Xuejiao Liao; Tongyang Xiao; Shen Qian; Jing Yuan; Haocheng Ye; Furong Qi; Chengguang Shen; Yang Liu; Lifei Wang; Xiaoya Cheng; Na Li; Qingxian Cai; Fang Wang; Jun Chen; Yingxia Liu; Yunfang Wang; Feng Zhang; Yang Fu; Xiaohua Tan; Lei Liu; Zheng Zhang

Another virological factor is that long-term virus residual in gut and other tissue, similar to SARS [26] . A recent study indicated that SARS-CoV-2 nucleic acid can persist in the digestive tract and feces for nearly 50 days [27] . Thus, extending detection time is necessary for the COVID-19 patients when they were discharged. However, our results show that adding anal swab derived RNA tested to be negative as discharge criterion did not significantly reduce the occurrence of RP patients. Thus other factor may be associated with the RP patients. We could not exclude sampling methodological factors including differential sampling and operational methods, sample quality, and technician expertise levels. Nor could we exclude immunological factors including low mucosal immune responses such as low IgA levels. These factors may take some uncertain risks leading the occurrence of RP patients [4, 27] . Future studies should reduce RP occurrence through using hyper-sensitive detection kit with hyper-specificity, combining detection of multiple samples with more immune markers.