Re-positive of SARS-CoV-2 test is common in COVID-19 patients after hospital discharge. Data from high standard post-discharge quarantined patients in Macao SAR, China.

During the pandemic of COVID-19, Macau faces tremendous pressure because it is a famous gambling and tourism city with the world's highest population density. The Macau government implemented decisive public health intervention to control the transmission of COVID-19, and there were only two independent outbreaks in Macau. In the second outbreak, all 35 cases were infected in foreign countries. They were quarantined in airborne infection isolation rooms for at least 14 days with reverse transcription-polymerase chain reaction (RT-PCR) tests after hospital discharge. Twelve (34.3%) of them had re-positive SARS-CoV-2 test results, and none of them presented any COVID-19 signs or symptoms during the entire quarantine period. In this study, the re-positive patients were more likely to be diagnosed in the early stage of the disease with a longer hospital stay. Virus re-infection is impossible in this high standard isolation setting, and reactivation is also unlikely, so that residual virus nucleic acid should be the possible reason for this phenomenon. Due to limited data about the risk of re-positive patients, it is better to quarantine patients after discharge for a prolonged period with repeat RT-PCR tests to minimize the community's potential risk, particularly in the regions with relative plenty of resources and low community infection rate such as Macau.

Minimizing the risk of community spread of COVID-19 via institutional quarantine of high-risk travelers with serial viral RNA testing: A successful experience from Macao SAR, China.

Macao, a special administrative region (SAR) of the People's Republic of China, is located in southern China and shares the border with mainland China. It is the most densely populated region in the world, with a population of 667400 and a total land area of 32.9 square kilometers in 2019. Since the first case diagnosed on January 22, 2020, there was a total of 45 laboratory-confirmed coronavirus disease 2019 (COVID-19) cases in Macao, of which 43 patients (96%) were imported cases. To date, all patients had been discharged successfully from Centro Hospitalar Conde de São Januário, a designated hospital to manage all COVID-19 patients in Macao. Eventually, no patient died, and no local community outbreak was noted. This opinion review describes the underlying factors that could have contributed to the successful experience in Macao SAR, China, which include the following: (1) Early implementation of containment measures; (2) Large-scale quarantine using hotel rooms to reduce the risk of a local outbreak; and (3) Multidisciplinary co-operation and transparency of information to the public. Although the successful experience in Macao SAR, China, may not be generalized to other regions, it should not be unreasonable to be well prepared with sufficient logistic support to conduct timely containment and early detection of episodic cases to prevent the backsliding of COVID-19 outbreak.

The common personal behavior and preventive measures among 42 uninfected travelers from the Hubei province, China during COVID-19 outbreak: a cross-sectional survey in Macao SAR, China.

BACKGROUND: The novel coronavirus diseases 2019 (COVID-19) caused over 1.7 million confirmed cases and cumulative mortality up to over 110,000 deaths worldwide as of 14 April 2020. A total of 57 Macao citizens were obligated to stay in Hubei province, China, where the highest COVID-19 prevalence was noted in the country and a "lockdown" policy was implemented for outbreak control for more than one month. They were escorted from Wuhan City to Macao via a chartered airplane organized by Macao SAR government and received quarantine for 14 days with none of the individual being diagnosed with COVID-19 by serial RNA tests from the nasopharyngeal specimens and sera antibodies. It was crucial to identify common characteristics among these 57 uninfected individuals. METHODS: A questionnaire survey was conducted to extract information such as behavior, change of habits and preventive measures. RESULTS: A total of 42 effective questionnaires were analyzed after exclusion of 14 infants and children with age under fifteen as ineligible for the survey and missing of one questionnaire, with a response rate of 97.7% (42 out of 43). The proportion of female composed more than 70% of this group of returners. The main reason for visiting Hubei in 88.1% of respondents was to visit relatives. Over 88% of respondents did not participate in high-risk activities due to mobility restriction. All (100%) denied contact with suspected or confirmed COVID-19 cases. Comparison of personal hygiene habits before and during disease outbreak showed a significant increase in practice including wearing a mask when outdoor (16.7% and 95.2%, P < 0.001) and often wash hands with soap or liquid soap (85.7% and 100%, P = 0.031).