ABSTRACT
Colombia announced the first case of severe acute respiratory syndrome coronavirus 2 on March 6, 2020. Since then, the country has reported a total of 4,240,982 cases and 106,544 deaths as of June 30, 2021. This motivates an investigation of the SARS-CoV-2 transmission dynamics at the national and regional level using case incidence data. Mathematical models are employed to estimate the transmission potential and perform short-term forecasts of the COVID-19 epidemic trajectory in Colombia. Furthermore, geographic heterogeneity of COVID-19 in Colombia is examined along with the analysis of mobility and social media trends, showing that the increase in mobility in July 2020 and January 2021 were correlated with surges in case incidence. The estimation of national and regional reproduction numbers shows sustained disease transmission during the early phase of the pandemic, exhibiting sub-exponential growth dynamics. Moreover, most recent estimates of reproduction number are >1.0 at the national and regional levels as of May 30, 2021. Further, the 30-day ahead short-term forecasts obtained from Richards model present a sustained decline in case counts in contrast to the sub-epidemic and GLM model. Nevertheless, our spatial analysis in Colombia shows distinct variations in incidence rate patterns across different departments that can be grouped into four distinct clusters. Lastly, the correlation of social media trends and adherence to social distancing measures is observed by the fact that a spike in the number of tweets indicating the stay-at-home orders was observed in November 2020 when the case incidence had already plateaued. Author summaryAs the COVID-19 pandemic continues to spread across Colombia, studies highlighting the intensity of the pandemic become imperative for appropriate resource allocation and informing public health policies. In this study we utilize mathematical models to infer the transmission dynamics of SARS-CoV-2 at the regional and national level as well as short-term forecast the COVID-19 epidemic trajectory. Moreover, we examine the geographic heterogeneity of the COVID-19 case incidence in Colombia along with the analysis of mobility and social media trends in relation to the observed COVID-19 case incidence in the country. The estimates of reproduction numbers at the national and regional level show sustained disease transmission as of May 30, 2021. Moreover, the 30-day ahead short-term forecasts for the most recent time-period (June 1-June 30, 2021) generated from the mathematical models needs to be interpreted with caution as the Richards model point towards a sustained decline in case incidence contrary to the GLM and sub-epidemic wave model. Nevertheless, the spatial analysis in Colombia shows distinct variations in incidence rate patterns across different departments that can be grouped into four distinct clusters. Lastly, the social media and mobility trends explain the occurrence of case resurgences over the time.
ABSTRACT
In order to identify the temporal change in the possible risk of superspreading events (SSE), we estimated the overdispersion parameter in two different periods of COVID-19 pandemic. We identified the possible risk of SSE was reduced 34% during the second epidemic period in South Korea.
ABSTRACT
In South Korea, 13,745 cases of COVID-19 have been reported as of 19 July, 2020. We used EpiEstim R package to investigate the time-varying reproduction numbers of the COVID-19 in the four most affected regions in South Korea: Seoul, Gyeonggi Province, Gyeongbuk Province, and Daegu. At the regional level, Seoul and Gyeonggi Province have experienced two waves with the first major peak of COVID-19 in early March, followed by the second wave in the first two weeks of June, with reproduction numbers in early May greater than 3.0. Gyeongbuk Province and Daegu are yet to experience a second wave of the disease, where the mean reproduction number reached values as high as 3.5-4.4. Our findings indicate that the loosening of the restrictions imposed by the government in May 2020 facilitated a second wave in the greater Seoul area. Article Summary LineThe loosening of the social distancing measures imposed by the Korean government in May 2020 has resulted in the second wave of COVID-19 in the greater Seoul area in the first two weeks of June, yielding reproduction numbers exceeding 3.0
ABSTRACT
This study aimed to explore the patterns of community health risk perception of coronavirus disease 2019 (COVID-19) in South Korea using Internet search data. Google and NAVER relative search volume data were collected using COVID-19-related terms in Korean language. Online queries were compared with the number of new COVID-19 cases and tests. Time series trends and Spearmans rank correlation coefficients showed that the number of COVID-19-related queries in South Korea increased during the local and international events; higher in women, certain age groups; and higher in affected areas, which represented the community health risk perception. Greater correlations were found in mobile searches compared to that of desktop searches, indicating the changing behavior in searching health online information. The use of both Google and NAVER RSV to explore the patterns of community health risk perception could be beneficial for targeting risk communication in several perspectives including time, population characteristics, and location. Article Summary LineThe use of both Google and NAVER RSV to explore the patterns of community health risk perception toward COVID-19 in South Korea could be beneficial for targeting risk communication in several perspectives including time, population characteristics, and location.
ABSTRACT
Background: In Korea, a total of 10,840 confirmed cases of COVID-19 including 256 deaths have been recorded as of May 9, 2020. The time-delay adjusted case fatality risk (CFR) of COVID-19 in Korea is yet to be estimated. Methods: We obtained the daily series of confirmed cases and deaths in Korea reported prior to May 9, 2020. Using statistical methods, we estimated the time-delay adjusted risk for death from COVID-19 in Daegu, Gyeongsangbuk-do, other regions in Korea, as well as the entire country. Results: Our model-based crude CFR fitted the observed data well throughout the course of the epidemic except for the very early stage in Gyeongsangbuk-do; this was partially due to the reporting delay. Our estimates of the risk of death in Gyeongsangbuk-do reached 25.9% (95% CrI: 19.6%-33.6%), 20.8% (95% CrI: 18.1%-24.0%) in Daegu and 1.7% (95% CrI: 1.1%-2.5%) in other regions, whereas the national estimate was 10.2% (95% CrI: 9.0%-11.5%). Conclusions: The latest estimates of CFR of COVID-19 in Korea are considerably high, even with the early implementation of public health interventions including widespread testing, social distancing, and delayed school openings. Geographic differences in the CFR are likely influenced by clusters tied to hospitals and nursing homes.
ABSTRACT
Since the first identified individual of 2019 novel coronavirus (COVID-19) infection on Jan 20, 2020 in South Korea, the number of confirmed cases rapidly increased. As of Feb 26, 2020, 1,261 cases of COVID-19 including 12 deaths were confirmed in South Korea. Using the incidence data of COVID-19, we estimate the reproduction number at 1.5 (95% CI: 1.4-1.6), which indicates sustained transmission and support the implementation of social distancing measures to rapidly control the outbreak.
