To better understand the epidemiology of SARS‐CoV‐2 reinfections, we analyzed national data from South Korean who were followed longitudinally from January 2020 to April 2022. We conducted a nationwide retrospective cohort study to estimate possible SARS‐CoV‐2 reinfection rates in all residents in South Korea, with at least two episodes of laboratory‐confirmed SARS‐CoV‐2 infection by reverse‐transcriptase polymerase chain reaction or rapid antigen test (RAT) performed at least 45 or more days between both episodes, between January 2020 and April 2022. There were 16 130 855 laboratory‐confirmed SARS‐CoV‐2 cases in South Korea, with 55 841 (346.2 per 100 000; or 0.3% of all infections) cases of possible reinfections. The reinfection rate has increased from 6.0 cases per 100 000 during Pre‐Delta period to 128.0 cases per 100 000 and 355.1 cases per 100 000 during Delta and Omicron periods, respectively. Persons with one dose of vaccination had the highest reinfection rate of 642.2 per 100 000, followed by unvaccinated persons (536.2/100 000) and two‐dose vaccinated persons (406.3/100 000). Our finding suggests that the majority of possible reinfections occurred following the emergence of new variants.

Wang S, et al. J Vet Sci. 2021 Apr;22(3):e37. https://doi.org/10.4142/jvs.2021.22.e37

Objectives: It is crucial to establish the characteristics of coronavirus disease 2019 (COVID-19) outbreaks at army training centers to develop preventive measures. Therefore, this study aimed to determine the COVID-19 transmission patterns and risk factors in a sequence of outbreaks at an army training center from June to August 2021.Methods: This study included 1,324 trainees at an army training center where outbreaks occurred from June to August 2021. The outbreak was qualitatively analyzed according to the period, attack rate, demographic characteristics, vaccination history, and living areas. An aerodynamic experiment was performed to evaluate aerosol transmission in living areas.Results: Three outbreaks occurred at the army training center from June to August 2021. The first, second, and third outbreaks lasted for 32, 17, and 24 days, and the attack rates were 12.8%, 18.1%, and 8.9%, respectively. Confirmed cases were distributed in all age groups. Recruits and the unvaccinated were at higher risk for COVID-19. The aerodynamic experiment verified the possibility of aerosol transmission within the same living area.Conclusion: COVID-19 transmission at army training centers should be minimized through quarantine and post-admission testing during the latency period as part of integrated measures that include facility ventilation, vaccination, indoor mask-wearing, and social distancing.

The human microbiota-associated (HMA) pig model provides a physiologically relevant platform that bridges preclinical and translational research. However, its use remains limited, with existing studies showing considerable variation in establishment methods. This scoping review systematically evaluates methodological frameworks, engraftment outcomes, and research applications of HMA pig models. Additionally, it highlights their strengths, limitations, and implications for future studies. We conducted a comprehensive literature search in PubMed, Web of Science, Scopus, and Directory of Open Access Journals, following PRISMA guidelines for Scoping Reviews. The review examines the methodological foundations of HMA pig model generation and proposes a minimal reporting framework to promote standardization. It synthesizes studies on human microbiota engraftment in pigs, identifying factors that influence colonization efficiency. Finally, it summarizes current applications, discusses persistent limitations and translational challenges, and outlines opportunities for future research. Overall, these integrated insights aim to foster standardized, reproducible protocols for HMA pig model preparation and guide advancements in the field.

왕성진, 홍사현, 장규식, 하진호, 강가람, 김영지, 김자은, 주수영, 최호용, 최장훈. Public Health Weekly Report 2025;18:1153-67. https://doi.org/10.56786/PHWR.2025.18.31.1