Objective  To describe epidemiological characteristics of discharged coronavirus disease 2019 (COVID-19) patients retested positive for viral nucleic acid in Shenzhen city and to provide evidences for prevention and control of the disease.

  Methods  We collected the data on all COVID-19 patients retested positive for viral nucleic acid at the time of discharge during the period from February 21 to April 22, 2020 in Shenzhen city and analyzed the data with descriptive statistics.

  Results  Among a total of 330 COVID-19 patients discharged during the period, 59 were retested positive for viral nucleic acid, with a cumulated rate of 17.9%. For the retested positive cases, the male to female ratio was 0.83 : 1 (24 versus 35); the age of the cases ranged 1 – 86 years, with a median of 38 years and the proportions of the cases aged 0 – 19, 20 – 59, and ≥ 60 were 15.2%, 71.2%, and 13.6%, respectively. The longest interval from the first-time discharge to the last detection positive for viral nucleic acid was 57 days. Among the discharged cases, the rate of retested positive for viral nucleic acid differed significantly by age groups (χ² = 17.070, P = 0.018) and specimen types (nasopharyngeal swab vs. anal swab: χ² = 26.367, P < 0.001), but did not varied significantly by gender (χ² = 0.838, P = 0.360) and quarantine days (χ² = 6.292, P = 0.098) based on Fisher exact test.

  Conclusion  Among discharged COVID-19 patients, the rate of retested positive for viral nucleic acid is related to the patients′ age and specimen type but not associated with gender and quarantine days and the positivity could remain for a long time in a few of the patients.