Analysis of re-positive nucleic acid conversion in patients recovered from COVID-19 in Tianjin

Objective To analyze the re-positive nucleic acid cases in patients recovered from coronavirus disease 2019 (COVID-19) in Tianjin, and to provide suggestions on making prevention and control strategies. Methods Among the 109 confirmed COVID-19 patients in Tianjin who were reported by the China Information System for Disease Control and Prevention, 8 patients re-positive for nucleic acid test after discharge were enrolled in this study. Their conditions after discharge were monitored by our group, including epidemiology, onset time, symptoms, and results of regular viral nucleic acid test. The epidemiological characteristics were analyzed. Results As of March 7, 2020, the positive rate of re-positive nucleic acid conversion in patients recovered from COVID-19 was 7.34% (8/109). The median days of disease was 20.5 (14.0~28.0) d in 8 re-positive cases, which was not statistically different from those with negative results after discharge. Among the viral nucleic acid-positive samples, fecal specimens or anal swabs accounted for 62.50% (5/8), and throat swabs for 37.50% (3/8). All 8 cases had identified epidemiological history. When the nucleic acid re-positive, 12.50% of them (1/8) had clinical symptoms, but they did not cause any secondary transmission. Conclusion Re-positiveness for nucleic acid test are found in the COVID-19 patients after discharge in Tianjin, but no one causes further transmission till now. It is recommended to add standards for fecal nucleic acid test during discharge and quarantine, regularly nucleic acid detection after the patient is discharged from the hospital.