Caution should be exercised for the detection of SARS-CoV-2, especially in the elderly

In December 2019, a pneumonia outbreak, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was first identified in Wuhan, China and presented a major threat to public health. Nationwide, there were more than 70 000 confirmed cases and 2500 deaths. Most patients were elderly, with severe disease. For acute respiratory infection, reverse-transcription polymerase chain reaction (RT-PCR) is routinely used to detect causative viruses in respiratory secretions. Coronavirus RNA can be detected from nose and throat swabs, sputum and other lower respiratory tract secretions, blood, and feces. Such specimens were examined by RT-PCR. Three targets, RdRP, E, and N genes were detected, indicating samples were positive for SARS-CoV-2. After patient recovery, a chest computed tomography examination, combined with SARS-CoV-2 RNA detection, confirmed diagnosis. However, some recovery patients with negative RNA tests turned RNA positive. The preliminary data is about 14% of discharged patients in Guangdong reported by the Guangdong Center for Disease Control (CDC). This is an important scientific issue. If samples are positive for SARS-CoV-2 RNA, patients should be managed according to infection source. Fortunately, there were no close contacts of second-generation cases. We herein report six SARS-CoV-2 cases confirmed in our hospital, for the changes of results of SARS-CoV-2 RNA should attract attention. Most patients were elderly, with a low Geriatric Nutritional Risk Index (GNRI). However, the association of the phenomenon with aging and GNRI has not yet been reported in detail. Further investigations are necessary to confirm and improve these findings. Similarly, discharged patient follow-up should be strengthened.