HealthDay News – Some patients with coronavirus disease 2019 (COVID-19) remain positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in sputum or feces after pharyngeal samples become negative, according to a research letter published online March 30 in the Annals of Internal Medicine.
Chen Chen, PhD, from Capital Medical University in Beijing, and colleagues examined the results of real-time quantitative fluorescence polymerase chain reaction (RT-qPCR) testing for SARS-CoV-2 RNA of sputum and fecal samples from a group of patients after conversion of the pharyngeal samples from positive to negative.
The researchers found that 22 of 133 patients admitted with COVID-19 from January 20 to February 27, 2020, had an initial or follow-up positive sputum or fecal sample paired with a follow-up negative pharyngeal sample. Eighteen of these patients were aged 15 to 65 years and 4 were children. The most common initial symptom at onset was fever, and 5 patients had at least one preexisting medical condition. A total of 545 specimens were collected from these patients, including 209, 262, and 74 pharyngeal, sputum, and feces samples, respectively. Sputum and feces samples remained positive for SARS-CoV-2 on RT-qPCR up to 39 and 13 days, respectively, after pharyngeal samples were negative.
“It is important to emphasize, however, that it is not known whether the positive RT-qPCR results for SARS-CoV2 observed here indicate that a patient continues to pose a risk for infection to others,” the authors write.