[Effectiveness of the "14 plus 7 day quarantine" and "nucleic acid plus total antibody testing" strategy for screening imported patients with COVID-19 in Xiamen].

Objective: To analysis effectiveness of the "14 plus 7 day quarantine" and "nucleic acid plus total antibody testing" strategy (combined screening strategy) for screenin the imported patients with COVID-19 in Xiamen. Methods: The study populations were overseas travelers arriving in Xiamen from March 17 to December 31, 2020, and overseas travelers who had quarantine outside Xiamen for less than 21 days from July 18 to December 31, 2020. Data were collected and analyzed on the timing of detection, pathways, and test results of the imported patients with COVID-19 after implementing combined screening strategy. Results: A total of 304 imported patients with COVID-19 were found from 174 628 overseas travelers and 943 overseas travelers from other cities. A total of 163 cases (53.6%) were diagnosed by multitime, multisite intensive nucleic acid testing after positive finding in total antibody testing. Among them, 27 (8.9%) were first positive for nucleic acid in 14 plus 7 day quarantine and 136 were first positive for nucleic acid in 14-day quarantine. Only 8 of these individuals were tested positive for nucleic acid after positive total antibody testing. The other 128 individuals were tested positive for nucleic acid after being negative for average 2.3 times (maximum of 6 times). Aditional 155 cases might be detected by using the combined "14 plus 7 day quarantine" and " nucleic acid plus total antibody testing" strategy compared with "14-day quarantine and nucleic acid testing" strategy, accounting for 51.0% of the total inbound infections. So the combined screening strategy doubled the detection rate for imported patients with COVID-19. No second-generation case caused by overseas travelers had been reported in Xiamen as of February 26, 2021. Conclusions: Xiamen's combined screening strategy can effectively screen the imported patients with COVID-19 who were first positive for nucleic acid after 14 day quarantine. Compared with "14 day quarantine and nucleic acid testing", the combined screening strategy improved detection rate and further reduced the risk of the secondary transmission caused by the imported patients with COVID-19.

Negative viral nucleic acid test of induced sputum: an additional criteria for COVID-19 patient's discharge.

OBJECTIVE: Concerns have been raised that patients with Coronavirus Disease 2019 (COVID-19) are still infectious with a re-positive nucleic acid test of the pharyngeal swab after hospital discharge. The aim of this study was to investigate the clinical relevance of induced sputum as an additional indicator for the current clinical discharge criteria of COVID-19 patients to prevent virus recurrence. PATIENTS AND METHODS: Twenty-one COVID-19 patients who met the national clinical discharge criteria were discharged from the hospital and tested daily for the presence of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) nucleic acid in their pharyngeal swabs and every other day for the presence of SARS-CoV-2 in their induced sputum. Once the patient's induced sputum was negative after two consecutive tests, testing was discontinued. RESULTS: Among 21 discharged patients from COVID-19, the first pharyngeal swab and induced sputum tests for viral nucleic acid were positive in 3 (14.3%) and 8 (38.1%) patients respectively. Induced sputum was significantly more positive than pharyngeal swab (p < 0.05). In our cohort, all pharyngeal swabs became negative at day 7, and all induced sputa turned negative at day 11 after discharge. Interestingly, patients with negative pharyngeal swabs experienced viral relapse, whereas patients with negative induced sputum did not revert to positivity. CONCLUSIONS: The detection rate of positive viral nucleic acid in induced sputum was high. Patients with negative induced sputum nucleic acid tests did not have a relapse of SARS-COV-2, indicating that viral nucleic acid testing of induced sputum should be used as an additional criterion for patients with national clinical discharge criteria COVID-19.

No infectious risk of COVID-19 patients with long-term fecal 2019-nCoV nucleic acid positive.

OBJECTIVE: It has recently been reported that some COVID-19 patients have long-term positive fecal nucleic acid after discharging from the hospital with negative nucleic acid in the respiratory tract, but it is unclear whether COVID-19 patients with positive long-term fecal nucleic acid tests have the risk of self-infection. PATIENTS AND METHODS: From January 25, 2020 to March 9, 2020, 5 COVID-19 patients with negative respiratory tract nucleic acid and positive fecal nucleic acid were observed and studied to explore whether these patients can re-infect themselves. Five patients with COVID-19 accompanied by diarrhea as the main gastrointestinal symptoms were carefully observed through clinical symptoms, imaging and other auxiliary examinations. The RT-PCR technology was used to continuously detect fecal and respiratory viral nucleic acids. The IgM antibody was detected on the 7th day of admission and IgM/IgG at the time of discharge. RESULTS: All 5 patients had symptoms of fever and diarrhea upon admission. The fecal nucleic acid was positive, as well as the throat swab was positive. All COVID-19 patients had positive IgM antibodies on the 7th day of admission and positive IgM and IgG at the time of discharge, and there were no abnormalities in the gastrointestinal examination on discharge. All 5 fecal nucleic acid tests were positive at the time of discharge. After continuous dynamic follow-up for 3-15 days, no clinical symptoms recurred, and the last nucleic acid test was negative. CONCLUSIONS: There is no risk of self-infection for COVID-19 patients with long-term 2019-nCoV nucleic acid positive in feces.