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Positive RT-PCR Test Results in Patients Recovered From COVID-19

Our take —

This case series of four SARS-CoV-2 infected healthcare workers in China showed that following clinical recovery and two negative RT-PCR test results, all cases re-tested positive by RT-PCR multiple times 5-18 days later despite no known additional exposure. While the sample size is small and the impact of antivirals during hospitalization on RNA testing in these patients is unknown, further evaluation of the implications of these findings on clinical outcomes and the potential for onward transmission post-recovery are warranted.

Study design

Case Series

Study population and setting

Four medical professionals with occupational exposure and laboratory confirmed SARS-CoV-2 in Wuhan, China were followed from January 1, 2020 to February 15, 2020. Demographic characteristics, laboratory findings, and radiological features were extracted from medical records, and after recovery, throat swabs were serially collected for RT-PCR analysis. Discontinuation of quarantine or hospital discharge was defined as absence of clinical symptoms, improved radiological abnormalities and two negative RT-PCR results ≥1 day apart.

Summary of Main Findings

Patients ranged in age from 30 to 36 years old, and two were male. Three experienced symptoms at onset, while one was asymptomatic. The disease severity among cases was characterized as mild to moderate. All patients had four subsequent positive RT-PCR results 5 – 18 days following discharge or quarantine (which required 2 negative RT-PCR tests 24 hours apart), though they remained asymptomatic, experienced no major clinical changes and had no new known exposure. No onward transmissions to family members were observed.

Study Strengths

The study defined recovery both as a subsiding of symptoms and as two negative test results. Multiple (four) post-recovery tests were performed among all cases, including tests using a kit from an alternate manufacturer, all of which were positive. These findings suggest that positive tests post-recovery could not likely all be explained by false-positives; similarly it is less likely that all four cases were false-negatives at time of recovery.

Limitations

This study was small. It only included four patients in a very specific age range, who were medical professionals and likely to have had higher levels of exposure, and who had mild to moderate disease. All patients were treated with antiviral medications, and it is unclear if they continued to take these medications following discharge/recovery and how this may have impacted viral test results. Additionally, the authors did not report viral load values, so it is not clear if there were trends in virus trajectory. At this time, it is also not known if detection of virus corresponds to infectious virus in long-term shedders.

Value added

This is one of the first studies to examine characteristics among recovered patients, and the findings have implications for how patients who are recovering should be managed, including considerations on how and when they can stop self-isolation.