Risk factors for redetectable positivity in recovered COVID‐19 children

Peng, Denggao; Zhang, Jing; Ji, Yiling; Pan, Dongming

OBJECTIVE: To identify the risk factors for redetectable positivity (RP), and to provide a basis for prevention and control of coronavirus disease‐2019 (COVID‐19) in children. METHODS: A retrospective study was performed on all pediatric patients diagnosed with COVID‐19. RP was defined as the positive result of real‐time reverse transcriptase polymerase chain reaction (RT‐PCR) for severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) after symptom resolution and discharge. Children were defined as being less than 18 years old. RESULTS: Fourteen out of 38 (36.8%) pediatric patients exhibited RP. Compared with the non‐RP group (n = 24), the RP group (n = 14) had more family cluster infections, relatively higher white blood cell (WBC) count and longer plasma prothrombin time (PT), while age and gender were insignificant. T lymphocyte subclassification was observed at five‐time points: the first test after admission, 2 weeks, and 1, 2, and 3 months after discharge. The RP group had a higher percentage and count of CD8+ T lymphocytes and lower CD4+/CD8+ ratio at 2 weeks, while a lower percentage and count of CD4+ T lymphocytes and lower CD4+/CD8+ ratio at 2 months. The positive rate of nasopharyngeal swabs by RT‐PCR was higher during the onset, while that of anal swabs was higher during the recovery of COVID‐19. CONCLUSIONS: Family cluster infection, higher WBC count, and longer PT are the early risk factors for RP in recovered COVID‐19 children. The dynamic changes in number and ratio of CD4+ and CD8+ T lymphocytes may be involved in prolonged SARS‐CoV‐2 clearance. Nasopharyngeal swabs sampling during the onset and anal swabs sampling during the recovery may improve the positivity rate of RT‐PCR.