Correction to: Transmission dynamics and control of two epidemic waves of SARS-CoV-2 in South Korea

Background After relaxing social distancing measures, South Korea experienced a resurgent second epidemic wave of coronavirus disease 2019 (COVID-19). In this study, we aimed to identify the transmission dynamics of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections and assess the impact of COVID-19 case finding and contact tracing in each epidemic wave. Methods We collected data on COVID-19 cases published by local public health authorities in South Korea and divided the study into two epidemic periods (19 January–19 April 2020 for the first epidemic wave and 20 April–11 August 2020 for the second epidemic wave). To identify changes in the transmissibility of SARS-CoV-2, the daily effective reproductive number (Rt) was estimated using the illness onset of the cases. Furthermore, to identify the characteristics of each epidemic wave, frequencies of cluster types were measured, and age-specific transmission probability matrices and serial intervals were estimated. The proportion of asymptomatic cases and cases with unknown sources of infection were also estimated to assess the changes of infections identified as cases in each wave. Results In early May 2020, within 2-weeks of a relaxation in strict social distancing measures, Rt increased rapidly from 0.2 to 1.8 within a week and was around 1 until early July 2020. In both epidemic waves, the most frequent cluster types were religious-related activities and transmissions among the same age were more common. Furthermore, children were rarely infectors or infectees, and the mean serial intervals were similar (~ 3 days) in both waves. The proportion of asymptomatic cases at presentation increased from 22% (in the first wave) to 27% (in the second wave), while the cases with unknown sources of infection were similar in both waves (22 and 24%, respectively). Conclusions Our study shows that relaxing social distancing measures was associated with increased SARS-CoV-2 transmission despite rigorous case findings in South Korea. Along with social distancing measures, the enhanced contact tracing including asymptomatic cases could be an efficient approach to control further epidemic waves.This work was supported by the Basic Science Research Program through the National Research Foundation of Korea, funded by the Korean Ministry of Education (NRF-2020R1I1A3066471). The funder of the study had no role in study design, analysis, interpretation of the data, or writing of the report

ATAD5 restricts R-loop formation through PCNA unloading and RNA helicase maintenance at the replication fork

R-loops are formed when replicative forks collide with the transcriptional machinery and can cause genomic instability. However, it is unclear how R-loops are regulated at transcription-replication conflict (TRC) sites and how replisome proteins are regulated to prevent R-loop formation or mediate R-loop tolerance. Here, we report that ATAD5, a PCNA unloader, plays dual functions to reduce R-loops both under normal and replication stress conditions. ATAD5 interacts with RNA helicases such as DDX1, DDX5, DDX21 and DHX9 and increases the abundance of these helicases at replication forks to facilitate R-loop resolution. Depletion of ATAD5 or ATAD5-interacting RNA helicases consistently increases R-loops during the S phase and reduces the replication rate, both of which are enhanced by replication stress. In addition to R-loop resolution, ATAD5 prevents the generation of new R-loops behind the replication forks by unloading PCNA which, otherwise, accumulates and persists on DNA, causing a collision with the transcription machinery. Depletion of ATAD5 reduces transcription rates due to PCNA accumulation. Consistent with the role of ATAD5 and RNA helicases in maintaining genomic integrity by regulating R-loops, the corresponding genes were mutated or downregulated in several human tumors

Turnover Intention among Field Epidemiologists in South Korea

The purpose of this study was to explore the level of occupational stress, job satisfaction, and turnover intention among Korean field epidemiologists, and to identify the factors that contribute to their turnover intention. We surveyed the Korean field epidemiologists in the cohort from 2016 to 2018 using the Occupational Stress Inventory, revised edition, and questionnaires developed from the Public Health Workforce Interest and Needs Survey. Fisher’s exact test was used to identify the association between sociodemographic characteristics, occupational stress, job satisfaction, and turnover intention. Overall, 17 Korean field epidemiologists participated in this study (response rate: 74%). More than half of field epidemiologists had turnover intention (53%), and it was less likely to be present in the field epidemiologists recruited from the civilian sector than those recruited from the military (adjusted odds ratio, 0.59; 95% confidence interval, 0.39–0.88). Furthermore, about two-thirds of field epidemiologists had a burden of occupational stress on Role Ambiguity (65%), and only one respondent expressed satisfaction with the job. There was no significant relation among the levels of occupational stress, job satisfaction, and turnover intention. In this study, the field epidemiologists recruited from the military were more likely to have turnover intention. Additional studies to identify possible ways to reduce turnover intention among the public health workforce are warranted

Community-acquired Legionnaires’ Disease in a Newly Constructed Apartment Building

Objectives Legionnaires’ disease (LD) is a severe type of pneumonia caused by inhalation of aerosols contaminated with Legionella. On September 22, 2016, a single case of LD was reported from a newly built apartment building in Gyeonggi province. This article describes an epidemiologic investigation of LD and identification of the possible source of infection. Methods To identify the source of LD, we interviewed the patient’s husband using a questionnaire based on the Legionella management guidelines from the Korea Centers for Disease Control and Prevention. Water samples from the site were collected and analyzed. An epidemiological investigation of the residents and visitors in the apartment building was conducted for 14 days before the index patient’s symptoms first appeared to 14 days after the implementation of environmental control measures. Results Legionella pneumophila serogroup 1 was isolated from the heated-water samples from the patient’s residence and the basement of the apartment complex. Thirty-two suspected cases were reported from the apartment building during the surveillance period, yet all were confirmed negative based on urinary antigen tests. Conclusions The likely source of infection was the building’s potable water, particularly heated water. Further study of effective monitoring systems in heated potable water should be considered

Temporal association between antibiotic use and resistance in Klebsiella pneumoniae at a tertiary care hospital

Abstract Background β-Lactam/β-lactamase inhibitors (BLBLIs) were introduced into clinical practice as an alternative to carbapenems for treating multi-drug–resistant Klebsiella pneumoniae infections. However, little is known about the relationship between BLBLI treatment and antimicrobial resistance. In this study, we investigated the trends and the temporal association between antibiotic use and antimicrobial resistance in K. pneumoniae isolates obtained between 2012 and 2016. Methods Data regarding quarterly consumption (total number of prescriptions per quarter) of all BLBLIs, all third-generation cephalosporins, and all fluoroquinolones at a tertiary care hospital were obtained from the Korean Health Insurance Review and Assessment Service. Susceptibility data (isolation rate of antibiotic resistance per quarter) were obtained from the existing database of the same tertiary hospital. Regression analysis was used to analyze annual trends and cross-correlations to assess the temporal association on a quarterly basis between antibiotic consumption and antibiotic resistance in K. pneumoniae. Results The rate of resistance to piperacillin/tazobactam in K. pneumoniae significantly increased over the study period (p < 0.01). The consumption of all BLBLIs was also found to be significantly correlated with the rate of resistance to piperacillin/tazobactam (β = 0.66; p < 0.01), ceftazidime (β = 0.54; p = 0.02), and levofloxacin (β = − 0.60; p = 0.01) with two-quarter lags. Furthermore, the consumption of all third-generation cephalosporins was significantly correlated with rates of K. pneumoniae resistance to ceftazidime (β = 0.64; p < 0.01) with a two-quarter lag and levofloxacin (β = 0.50; p = 0.03) with a quarter lag. The consumption of all fluoroquinolones correlated with resistance rates to ceftazidime (β = 0.14; p < 0.01) with a two-quarter lag. Conclusions The rate of resistance to piperacillin/tazobactam in K. pneumoniae increased significantly over the study period and was significantly correlated with BLBLI consumption. While BLBLIs can potentially be utilized as an alternative to carbapenems, our findings reinforce concerns of resistance to these drugs. Further research is needed to understand the implications on resistance of utilizing BLBLIs as a carbapenem-sparing option

Single Molecule Measurements Reveal Conformational Transitions During DNA Clamp Loading and Unloading

Proliferation cell nuclear antigen (PCNA) is a DNA clamp, playing an important role of providing a ??????platform?????? for various enzymes during DNA replication. The loading of the closed trimeric ring of PCNA into duplex DNA requires the ATP-dependent activity of replication factor C (RFC) complex. The unloading of PCNA from chromatin is crucial for the regulation of replication process and maintaining genomic stability and it was recently found that ATAD5 protein is complexed with RFC-like complex (RLC) to get involved in the unloading of PCNA. However, the molecular mechanisms of PCNA loading and unloading processes have remained poorly understood. Here, we report direct observation of the loading and unloading dynamics of human PCNA driven by RFC and ATAD5-RLC complexes, respectively, by single molecule fluorescence resonance energy transfer measurements. Distinct conformational stages during PCNA loading were clearly detected that represent open and closed conformations of PCNA trimer and another loading intermediate that possibly triggers the dissociation of RFC complex. The unloading of PCNA occurred upon binding ATAD5-RLC complex through an intermediate conformation, but not requiring the hydrolysis of ATP, which is later employed to recycle PCNA and ATAD5-RLC complexes. Our findings present a mechanistic model of the clamp loading/unloading dynamics and bring implications on the mechanism controlling the exclusive functions of RFC and ATAD5-RLC complexes in the loading and unloading processes, respectively. It further provides a platform to study how PCNA controls the exchange of various replication enzymes

Collateral Impact of Public Health and Social Measures on Respiratory Virus Activity during the COVID-19 Pandemic 2020&ndash;2021

Many countries have implemented public health and social measures (PHSMs) to control the spread of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Although the PHSMs are targeted at SARS-CoV-2 transmission control, they directly or indirectly impact the epidemiology of different respiratory viral diseases. The purpose of this study was to investigate the collateral impact of PHSMs used during the coronavirus disease 2019 (COVID-19) pandemic on the epidemiology of other respiratory viruses, including influenza, parainfluenza, respiratory syncytial virus, rhinovirus, and adenovirus infections. We conducted a systematic review of the published literature on changes in the incidence of respiratory viral diseases and detection rates of the respiratory viruses during COVID-19 pandemic, lasting from 2020&ndash;2021, published between December 2019 and March 2022 in PubMed, Embase, and Cochrane Library databases. We identified an overall decrease of 23&ndash;94% in the incidence of respiratory viral diseases and a decrease of 0&ndash;98% in the detection of the viruses. Our study suggests that the PHSMs implemented during COVID-19 pandemic reduced the incidence of respiratory viral diseases and transmission of respiratory viruses. At the time of this study, and as governments relax PHSMs, public health authorities should prepare for a probable increase in the burden of respiratory viral diseases

The impact of expanded brucellosis surveillance in beef cattle on human brucellosis in Korea: an interrupted time-series analysis

Abstract Background Korean surveillance program for bovine brucellosis was improved by extending it to beef slaughterhouses and by pre-movement testing of bulls on May 2005 (Intervention 1). The bovine brucellosis surveillance program was further extended to beef cattle farms with more than 10 heads of cattle on June 2006 (Intervention 2). Methods To quantify the temporal relationship between bovine and human brucellosis, a time-series analysis was conducted using Korean national notification data reported between January 2004 and December 2014. Results Our findings indicate that while during the pre-intervention phase (January 2004 to March 2005) there was no significant temporal relationship between the incidences of bovine and human brucellosis, significant temporal relationships were observed after Intervention 1 (June 2005 to June 2006, no lag, β = 0.57, p = 0.04), and Intervention 2 (July 2006 to June 2007, 1-month lag, β = 0.65, p = 0.03). Furthermore, significant changes in incidence in human were observed after Intervention 1 (β = − 0.17 per 10 million-people, p = 0.03) and Intervention 2 (β = − 0.19 per 10 million-people, p = 0.04). Conclusions These findings indicated the changes of a nationwide comprehensive surveillance programme targeting all cattle is required for effective reduction in the human population