The characteristics of 527 discharged COVID-19 patients undergoing long-term follow-up in China

Highlights • Juvenile COVID-19 patients have faster time to RP result than any other aged groups. • Sampling from digestive tract may be better in identifying RP. • No marked difference on imaging change between RP and NRP patients was observed. • Nearly three-quarters of patients had protective antibodies 6 months post-discharge. • The disappearance rate of antibody is more rapid in juveniles than adults.
Background Almost a year after the outbreak of coronavirus disease 2019 (COVID-19), numerous hospitalized COVID-19 patients have recovered. However, little is known about the long-term follow-up (>2 months) of discharged patients. Methods We enrolled 527 discharged COVID-19 patients in a study from February 5 to March 11, 2020. These patients’ basic characteristics, imaging features, nucleic acid detection results, and antibody levels were retrospectively reviewed. Results of the 527 discharged patients, 32 (6.1%) had re-detectable positive (RP) nucleic acid results for SARS-CoV-2 during follow-up examinations with 11 and four detections entailing stool samples and anal swabs, respectively, rather than respiratory samples. Juveniles were more accessible to “infection recurrence” than other age groups, with shorter time spans for RP RNA tests (an average of 8.8 days [6.0–9.0 days]), while the reverse was true for the middle-aged group (17.5 days on average [14.0-17.5 days]). Similar improvements in the imaging features of both RP and none RP (NRP) groups were observed. Negative antibody detections in patients 3 and 6 months after discharge were 14.2% and 25.0%, respectively. Cases evidencing negative antibodies were more common among juvenile patients (40% vs. 15.6%, p = 0.03) 6 months post-discharge. Conclusions 6.1% of 527 discharged patients showed RP status, which may be easier to be identified from stool samples than from other samples. Given the dropping rate of SARS-CoV-2 antibody, reinfection may happen especially in juvenile patients (age less than 18 years). Our findings have implications for the long-term management of recovered COVID-19 patients.