Emerg Microbes Infect. 2020 Nov 16:1-28. doi: 10.1080/22221751.2020.1852058. Online ahead of print.
Following acute infection, individuals with coronavirus disease 2019 (COVID-19) may still shed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA. However, limited information is available regarding the active shedding period or whether infectious virus is also shed. Here, we monitored the clinical characteristics and virological features of 38 patients with COVID-19 (long-term carriers) who recovered from the acute disease, but still shed viral RNA for over 3 months. The median carrying history of the long-term carriers was 92 days after the first admission, and the longest carrying history was 118 days. Negative and positive viral RNA-shedding fluctuations were observed. Long-term carriers were mostly elderly people (65 years old, median age) with a history of mild infection. Infectious SARS-CoV-2 RNA was isolated from the respiratory tract (sputum), where high viral RNA and protein levels were found. Real-time polymerase chain reaction experiments showed that the viral load in long-term carriers was significantly lower (median cycle threshold [Ct] = 32) than in patients with acute infection (median Ct = 27). All nine full-length genomes of samples obtained in March-April 2020 matched early viral clades circulating in January-February 2020, suggesting that these patients persistently carried SARS-CoV-2 and were not re-infected. IgM and IgG antibodies and neutralizing-antibody profiles were similar between long-term carriers and recovered patients with similar disease courses. In summary, although patients with COVID-19 generated neutralizing antibodies, they may still shed infectious SARS-CoV-2 for over 3 months. These data imply that patients should be monitored after discharge to control future outbreaks.