ABSTRACT
BACKGROUND: On February 21, 2020, 2 coronavirus disease 2019 (COVID-19) cases in pilgrim travelers from Korea to Israel were identified. We investigated the source of infection, clinical features of COVID-19, and transmission potential of presymptomatic and asymptomatic cases. METHODS: All 39 pilgrim travelers were aggressively tested for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Their clinical features and possible source of infection were investigated by interview and review of their medical records. Ten confirmed cases without symptoms at the first sampling dates were selected for follow-up reverse transcription polymerase chain reaction tests. RESULTS: Of 39 pilgrim travelers, 30 (77%) were positive for SARS-CoV-2. Among the 30 positive COVID-19 cases, 4 (13%) were asymptomatic. Available follow-up cycle threshold values from 10 cases gradually increased over time and were lower during the presymptomatic period than during the postsymptomatic period. Out of 328 contacts related to the COVID-19 cases in the pilgrim travelers, 22 additional cases (7%) were confirmed with SARS-CoV-2 infections. Three tertiary cases were identified to be transmitted by presymptomatic secondary cases. CONCLUSION: To prevent transmission of COVID-19, we need to focus on presymptomatic and asymptomatic cases, and massive testing for SARS-CoV-2 is required. More research about the possibility of presymptomatic transmission over 2 days before symptom onset is required.
Subject(s)
COVID-19/epidemiology , COVID-19/transmission , Travel , Aged , Asymptomatic Infections/epidemiology , COVID-19 Nucleic Acid Testing , Communicable Disease Control , Disease Outbreaks , Female , Humans , Israel , Male , Middle Aged , Polymerase Chain Reaction , Real-Time Polymerase Chain Reaction , Republic of KoreaABSTRACT
OBJECTIVES: Coronavirus disease 2019 (COVID-19) outbreaks in nursing facilities can easily lead to a high rate of infection and fatality. A surge in newly infected cases in the first quarter of 2020 in Gyeongsan-si, in the Republic of Korea, was followed by several outbreaks in nursing facilities in the same area. The aim of this study is to report on the epidemiological investigation and the management to reduce the infection rate in nursing facilities for older adults. METHODS: The municipal government and the Korea Centers for Disease Control and Prevention performed an epidemiological investigation into 5 nursing facilities that reported a high number of COVID-19 infection cases from February to May 2020. COVID-19 infected cases in the facilities were investigated to identify the infection routes, and the fatality rate of the 5 facilities. RESULTS: The 5 facilities had a combined fatality rate of 12.2% (9 deceased among the 74 infected cases). The median age of the deceased was 87 years old (range: 82-91). The infection was first identified on February 27th, 2020, peaked on March 6th, and was last detected on March 24th, 2020. CONCLUSION: Difficulties specific to such facilities included the delay in the recognition of symptoms and limitation in distancing. Tailored strategies such as daily monitoring of symptoms and proactive COVID-19 screening of quarantined residents, contributed to a decline in the infections in the facilities.