Jae-Sik Jeon, Insoo Rheem, and Jae Kyung Kim. Korean J Clin Lab Sci. 2017;49:15-21. https://doi.org/10.15324/kjcls.2017.49.1.15

Background: Sexually transmitted infections (STIs) can have serious consequences, and the global STI incidence remains high. However, there is little information on the frequency of STIs with multiple pathogens according to age. Accordingly, we conducted a study to determine the trends of coinfection with sexually transmitted pathogens according to age in the Republic of Korea from 2018 to 2020. Methods: From January 2018 to December 2020, 65,191 samples of swab, urine, and other types submitted for STI screening were obtained from U2Bio Co. Ltd. (Seoul, Republic of Korea). Multiplex polymerase chain reaction, a sensitive and rapid method for simultaneous detection of STIs caused by multiple different pathogens, was performed using an AccuPower STI4C‐Plex Real‐Time PCR kit, AccuPower STI8A‐Plex Real‐Time PCR kit, and AccuPower STI8B‐Plex Real‐Time PCR kit with an Exicycler 96 Real‐Time Quantitative Thermal Block. Results: Of the 65,191 samples tested, 35,366 (54.3%) tested positive for one or more sexually transmitted pathogens. The prevalence of coinfections with two or more sexually transmitted pathogens was inversely proportional to age. Furthermore, the rates of coinfection with sexually transmitted pathogens and age distribution differed according to sex and the sexually transmitted pathogen type. Conclusion: This study confirmed that a significant proportion of patients with STIs are coinfected with multiple pathogens. Public health managers could use these results to recognize and prevent STIs according to age.

A Noticeable Change in Indoor Radon Levels After Platform Screen Doors Installation in Seoul Subway Station Subway;Platform screen doors (PSD);Radon concentration;Solid-state nuclear track detectors (SSNTDs);Radon map; Platform screen doors (PSD) installed at 289 stations in Seoul metropolitan subway from November 2005 to December 2009, are expected to prevent death from a fall and improve air quality. In this study, we systematically surveyed changes in radon concentrations before and after PSD installation in Seoul metropolitan subway stations. By solid-state nuclear track detectors (SSNTD), the radon concentrations before and after the PSD installation were measured at 54 stations of 6 lines from 2 to 7 reported to have relatively high radon concentrations. Mean radon concentrations at platforms were decreased by approximately 56% from 121.7 Bq/$m^3$ to 54.0 Bq/$m^3$. Before PSD installation, mean radon concentrations were in the decreasing order for subway lines 7, 5, 6, 3, 4 and 2. On the other hand, after PSD installation the order was changed to 5, 6, 7, 3, 4 and 2. According to a radon map of Seoul metropolitan subway, the number of platforms where radon concentration over was 74 Bq/$m^3$ decreased from 38 to 12 after PSD installation.

We investigated respiratory virus epidemiology in older adults across pre-pandemic (2007–2019), pandemic (2020–2022), and post-pandemic (2023–2024) periods, focusing on how public health interventions shaped surveillance, prevalence, and sex-specific trends. We conducted a retrospective cross-sectional study at a 1000-bed tertiary hospital in the Republic of Korea during 2007–2024, analyzing 4692 nasopharyngeal swab specimens collected from adults aged ≥ 65 years with suspected respiratory infections during 2007–2024. The specimens were tested for 15 respiratory viruses using multiplex real-time polymerase chain reaction. The outcomes included virus-specific detection rates and seasonal, sex-based and temporal trends before and after the COVID-19 pandemic. During the pre-pandemic period, older adults accounted for 13.2% of the tested individuals, which significantly increased to 52.0% in the later periods. Influenza A was the most frequently detected virus, followed by rhinovirus and human metapneumovirus. Influenza, RSV A/B, and coronaviruses 229E and OC43 showed peak positivity in winter, parainfluenza virus type 3 peaked in summer, and rhinovirus circulated year-round. Virus circulation was markedly suppressed during 2020–2022 and partially rebounded during 2023–2024. This study highlights the shift in diagnostic access and epidemiologic patterns of respiratory virus infections in older adults following the COVID-19 pandemic.

Background/Objectives: Respiratory syncytial virus A (RSV A) is the leading cause of respiratory infections, particularly in vulnerable populations. This study aimed to investigate the long-term epidemiological trends of RSV A infection in the Republic of Korea over an 18-year period (2007–2024), with emphasis on age, sex, and seasonal differences. Methods: A total of 23,284 nasopharyngeal swab specimens were analyzed by multiplex real-time PCR. Statistical comparisons were performed using the chi-square test. Results: The RSV A-positivity rate was highest in 2007 (19.7%) and lowest in 2021 (0.1%) (p < 0.001). Infants (0 years) exhibited the highest infection rate (18.5%, 95% CI: 17.3–19.6), whereas adults aged 20–64 years and older adults showed significantly lower rates (0.7% and 0.9%, respectively). Seasonal peaks occurred in winter (15.3%) and autumn (14.7%), indicating earlier onset of RSV A circulation. No significant difference was found between sexes (p = 0.196). Conclusions: This study provides the first long-term retrospective analysis of RSV A trends in the Republic of Korea and reveals a shift toward an earlier seasonal onset. These findings support the need for earlier preventive strategies and optimized vaccination timing, particularly for high-risk groups, such as infants. These findings underscore the importance of seasonal variation and the potential influence of environmental factors, such as ambient temperature, relative humidity, and geographic latitude, on RSV A transmission patterns in Korea, although these variables were not directly analyzed in the present study and warrant further investigation.