Clinical, immunological and virological characterization of COVID-19 patients that test re-positive for SARS-CoV-2 by RT-PCR

Journal article

Background:
Some COVID-19 cases test positive again for SARS-CoV-2 RNA following negative test results and discharge, raising questions about the meaning of virus detection. Better characterization of re-positive cases is urgently needed.

Methods:
Clinical data were obtained through Guangdong's COVID-19 surveillance network. Neutralization antibody titre was determined using microneutralization assays. Potential infectivity of clinical samples was evaluated by cell inoculation. SARS-CoV-2 RNA was detected using three different RT-PCR kits and multiplex PCR with nanopore sequencing.

Findings:
Among 619 discharged COVID-19 cases, 87 re-tested as SARS-CoV-2 positive in circumstances of social isolation. All re-positive cases had mild or moderate symptoms at initial diagnosis and were younger on average (median, 28). Re-positive cases (n = 59) exhibited similar neutralization antibodies (NAbs) titre distributions to other COVID-19 cases (n = 218) tested here. No infectious strain could be obtained by culture and no full-length viral genomes could be sequenced from re-positive cases.

Interpretation:
Re-positive SARS-CoV-2 cases do not appear to be caused by active reinfection and were identified in ~14% of discharged cases. A robust NAb response and potential virus genome degradation were detected in almost all re-positive cases, suggesting a substantially lower transmission risk, especially through respiratory routes.

Authors: Lu, J; Peng, J; Xiong, Q; Liu, Z; Lin, H

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Elsevier
• Journal: EBioMedicine
• Volume: 59
• Article number: 102960
• Publication date: 2020-08-24
• Acceptance date: 2020-07-31
• DOI: 10.1016/j.ebiom.2020.102960
• EISSN: 2352-3964
• Pmid: 32853988
• Language: English
• Keywords: virology; SARS-CoV-2; COVID-19; FFR; neutralizing antibody; re-positive