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The fourth vaccination dose confers additional protective immunity against severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection in individuals with no prior coronavirus disease‐19 (COVID‐19). However, its immunological benefit against currently circulating BA.4/5 is unclear in individuals who have received a booster shot and been infected with Omicron variant BA.1/2. We analyzed immune responses in whom had been boosted once and did not have COVID‐19 (n = 16), boosted once and had COVID‐19 when BA.1/2 was dominant in Korea (Hybrid‐6M group, n = 27), and boosted twice and did not have COVID‐19 (Vx4 group, n = 15). Antibody binding activities against RBDo BA.1 and RBDo BA.4/5, antigen‐specific memory CD4+ and CD8+ T‐cell responses against BA.4/5, and B‐cell responses against SARS‐CoV‐2 wild‐type did not differ statistically between the Hybrid‐6M and Vx4 groups. The humoral and cellular immune responses of the Hybrid‐6M group against BA.4/5 were comparable to those of the Vx4 group. Individuals who had been boosted and had an Omicron infection in early 2022 may not have high priority for an additional vaccination. [ABSTRACT FROM AUTHOR]

Before 2014, the only test used for anonymous voluntary human immunodeficiency virus (HIV) screening at public health centers (PHCs) in the Republic of Korea was an enzyme-linked immunosorbent assay (ELISA), which takes around 3 days to obtain results. In 2014, to encourage voluntary anonymous HIV screening tests, the Seoul Metropolitan Government adopted a rapid HIV screening test at PHCs. The rapid HIV screening test was introduced at four PHCs in 2014 and all 25 PHCs after 2015. We compared the numbers of HIV screening tests and confirmed positive individuals before and after introduction of the rapid HIV screening test. In 2012–2013, before the introduction of rapid HIV screening test, an average of 330 HIV screening tests were performed monthly (355 in 2012 and 305 in 2013) and 69 individuals were confirmed to have HIV in 2012 and 93 in 2013. After the introduction of the rapid HIV screening test, anonymous voluntary HIV screening increased to a monthly average of 447 tests in 2014, 2099 in 2015, and 2409 in 2016. These identified 38 new cases in 2014, 116 in 2015, and 143 in 2016. Adoption of the rapid HIV screening test has increased the number of HIV screening tests and confirmed cases. [ABSTRACT FROM AUTHOR]

To identify the factors associated with perceived unmet medical needs in human immunodeficiency virus (HIV)-infected adults, we analyzed the results from a series of city-wide cross-sectional surveys of HIV-infected adults living in Seoul, Korea. Multivariate logistic regression analysis was used to identify factors related to unmet medical needs. Among the 775 subjects included in the study, 15.4% had perceived unmet medical needs. Significant factors included age group (35-49 years; adjusted odds ratio [aOR], 1.80; 95% confidence interval [CI], 1.06-3.06), lower monthly income (aOR, 3.75 for the <$900/mo group and 2.44 for the $900-$1800/mo group; 95% CI, 1.68-8.35 and 1.18-5.04, respectively), beneficiaries of the National Medical Aid Program (aOR, 1.78; 95% CI, 1.01-3.17), recent CD4 cell counts <500/μL (aOR, 1.53; 95% CI, 1.01-2.33). Taken together, these data reveal strong associations of middle age and low socioeconomic status with perceived unmet medical needs among HIV-infected adults. [ABSTRACT FROM AUTHOR]

Many studies have investigated risk factors for suicidal ideation and suicide attempt; however, most have failed to show differences in risk factors between suicidal ideation and suicide attempt among the human immunodeficiency virus (HIV)-infected population. This study was designed to identify differences in risk factors between suicidal ideation and suicide attempts among HIV-infected adults in Seoul. A face-to-face survey of 457 HIV-infected adults was conducted by the Seoul Metropolitan Government in 2013. Multivariate logistic regression analysis was used to identify factors associated with suicidal ideation and suicide attempt. Among 422 participants, 44% had suicidal ideation, and 11% had suicide attempts. The independent risk factors for suicidal ideation were young and middle age, living with someone, history of AIDS-defining opportunistic disease, history of treatment for depression, lower social support, and psychological status. Beneficiaries of National Medical Aid, economic barriers to treatment, history of treatment for depression, and lower psychological status were independently associated with suicide attempts. Patients with HIV in Korea were treated without cost in some centers. Thus, experiencing an economic barrier to treatment might be due in part to ignorance of HIV care policies. Our findings indicate that suicide attempts are associated with socioeconomic factors and information inequality regarding medical care. In conclusion, suicidal ideation closely associated with the psychosocial factors, whereas suicide attempt demonstrates a stronger association with socioeconomic factors. Suicide prevention measures should be implemented to provide information to help HIV-infected patients. [ABSTRACT FROM AUTHOR]

We investigated the kinetics of serologic responses to Middle East respiratory syndrome coronavirus (MERS-CoV) infection by using virus neutralization and MERS-CoV S1 IgG ELISA tests. In most patients, robust antibody responses developed by the third week of illness. Delayed antibody responses with the neutralization test were associated with more severe disease. [ABSTRACT FROM AUTHOR]

Background: Scrub typhus is an endemic disease in Asia. It has been a rural disease, but indigenous urban cases have been observed in Seoul, South Korea. Urban scrub typhus may have a significant impact because of the large population. Methods: Indigenous urban scrub typhus was epidemiologically identified in Seoul, the largest metropolitan city in South Korea, using national notifiable disease data from 2010 to 2013. For detailed analysis of clinical features, patients from one hospital that reported the majority of cases were selected and compared to a historic control group. Chigger mites were prospectively collected in the city using a direct chigger mite-collecting trap, and identified using both phenotypic and 18S rDNA sequencing analyses. Their infection with Orientia tsutsugamushi was confirmed by sequencing the 56-kDa antigen gene. Results: Eighty-eight cases of urban scrub typhus were determined in Seoul. The possible sites of infection were mountainous areas (56.8%), city parks (20.5%), the vicinity of one's own residence (17.0%), and riversides (5.7%). Eighty-seven chigger mites were collected in Gwanak mountain, one of the suspected infection sites in southern Seoul, and seventy-six (87.4%) of them were identified as Helenicula miyagawai and eight (9.2%) as Leptotrombidium scutellare. Pooled DNA extracted from H. miyagawai mites yielded O. tsutsugamushi Boryong strain. Twenty-six patients from one hospital showed low APACHE II score (3.4 ± 2.7), low complication rate (3.8%), and no hypokalemia. Conclusions: We identified the presence of indigenous urban scrub typhus in Seoul, and a subgroup of them had mild clinical features. The chigger mite H. miyagawai infected with O. tsutsugamushi within the city was found. In endemic area, urban scrub typhus needs to be considered as one of the differential febrile diseases and a target for prevention. Author Summary: Scrub typhus is one of the high burdened infectious diseases in endemic rural areas. Our study showed that the disease could be endemic in urban areas. Indigenous urban scrub typhus may also have significant impact in terms of a disease burden and differential diagnosis. A low rate of characteristic eschar and skin rash may make the clinical suspicion more troublesome. Scrub typhus is the 3rd most frequent notifiable infectious disease in South Korea. Seoul is a densely populated capital city located in northwestern South Korea. We epidemiologically identified indigenous urban cases. A subgroup of them showed mild clinical characteristics. Direct mite collection from a suspected infection site, Mt. Gwanak in Seoul, showed that Helenicula miyagawai (87.4%) and Leptotrombidium scutellare (9.2%) were the dominant species. In addition, O. tsutsugamushi-specific gene, tsa56, was identified in a fraction of the collected H. miyagawai. The 18S rDNA sequencing of the chigger mites was complementarily helpful for the differentiation of species. Our data are from one region, but urban scrub typhus is likely a scenario in endemic areas. Urban areas should be included as possible locations for scrub typhus. [ABSTRACT FROM AUTHOR]

Summary: Objective: To investigate the risk factors for late presentation in the Republic of Korea, where massive mandatory screening for HIV infection was conducted by the government until the late 1990s. Methods: Data over the period 1987–2008 were analyzed from HIV patients for whom records of CD4 cell counts within 3 months of HIV diagnosis were available. Using multivariate logistic regression analysis including demographic and clinical variables, we examined factors associated with late presentation, defined as having a CD4 cell count of less than 200 cells/mm3 at the time of diagnosis. Results: Of a total of 994 patients with a new diagnosis of HIV infection, 405 (41%) were late presenters. As the proportion of patients diagnosed by mandatory screening decreased over time (31% in 1987–1998 versus 8% in 1999–2008, P < 0.001), the proportion of late presenters increased (31% in 1987–1998 versus 43% in 1999–2008, P = 0.007). The independent risk factors for late presentation were older age (adjusted odds ratio [aOR], per increase of 10 years, 1.31; 95% confidence interval [CI], 1.15–1.49; P < 0.001), male sex (aOR, 1.74; 95% CI, 1.03–2.95; P = 0.040), negativity for VDRL (aOR, 1.58; 95% CI, 1.16–2.14; P = 0.003), and diagnosis after 1999 (aOR, 1.64; 95% CI, 1.05–2.56; P = 0.031). Conclusions: Older age, male sex, negativity for VDRL, and diagnosis after 1999, were associated with late presentation, and the proportion of late presenters increased after the mandatory testing policy was abolished. [ABSTRACT FROM AUTHOR]

Little is known about differences between immune reconstitution inflammatory syndrome (IRIS) and non-IRIS lymphoma in HIV patients on antiretroviral therapy (ART). The aim of this study was to describe the characteristics of IRIS and non-IRIS lymphoma in Korean HIV-positive patients on ART compared with lymphoma in those off ART. Of 1490 patients, 41 (3%) had lymphoma. Of these, 27 cases (66%) were classified as lymphoma off ART, eight as IRIS lymphoma, and six as non-IRIS lymphoma on ART. Hodgkin lymphoma was significantly more common among patients with non-IRIS lymphoma on ART than among those with lymphoma off ART (P = 0.005), whereas there was no Hodgkin lymphoma among IRIS lymphoma. Stage IV lymphoma was significantly rarer in non-IRIS lymphoma on ART than in lymphoma off ART (P = 0.007). Non-IRIS lymphoma on ART tends to have a better survival rate than lymphoma off ART (Kaplan-Meier survival analysis, P = 0.167), while IRIS lymphoma exhibited a survival rate similar to lymphoma off ART (P = 0.618). In Korean HIV-positive patients, there were significantly more cases of Hodgkin lymphoma of a less advanced stage in non-IRIS lymphoma on ART than in lymphoma off ART, in contrast to IRIS lymphoma. [ABSTRACT FROM AUTHOR]

Background: After the Middle East respiratory syndrome coronavirus outbreak in Korea in 2015, the Government established a strategy for infection prevention to encourage infection control activities in hospitals. The new policy was announced in December 2015 and implemented in September 2016. The aim of this study is to evaluate how infection control activities improved within Korean hospitals after the change in government policy. Methods: Three cross-sectional surveys using the WHO Hand Hygiene Self-Assessment Framework (HHSAF) were conducted in 2013, 2015, and 2017. Using a multivariable linear regression model, we analyzed the change in total HHSAF score according to survey year. Results: A total of 32 hospitals participated in the survey in 2013, 52 in 2015, and 101 in 2017. The number of inpatient beds per infection control professionals decreased from 324 in 2013 to 303 in 2015 and 179 in 2017. Most hospitals were at intermediate or advanced levels of progress (90.6% in 2013, 86.6% in 2015, and 94.1% in 2017). In the multivariable linear regression model, total HHSAF score was significantly associated with hospital teaching status (β coefficient of major teaching hospital, 52.6; 95% confidence interval [CI], 8.9 to 96.4; P = 0.018), beds size (β coefficient of 100 beds increase, 5.1; 95% CI, 0.3 to 9.8; P = 0.038), and survey time (β coefficient of 2017 survey, 45.1; 95% CI, 19.3 to 70.9; P = 0.001). Conclusions: After the new national policy was implemented, the number of infection control professionals increased, and hand hygiene promotion activities were strengthened across Korean hospitals. [ABSTRACT FROM AUTHOR]

• The positivity rates of culture in tuberculous spondylitis were 69.0-85.3%. • The culture positivity rates were different according to biopsy methods and sites. • Targeting paraspinal tissues during needle biopsy might be the best method. We aimed to evaluate the mycobacterial culture positivity rates according to biopsy methods and sites in patients with tuberculous spondylitis (TS) and identify which tissues are the best sites for the diagnosis of TS. We retrospectively identified and reviewed medical records of all patients with TS in three university-affiliated hospitals in the Republic of Korea from January 2003 to December 2020. TS was diagnosed by culture or histopathologic examination of vertebral bodies or paraspinal tissues and characteristic clinical and radiologic features. Patients with TS who received a needle biopsy or underwent surgical biopsy were investigated. The sites of needle biopsy were classified as vertebral bodies or paraspinal tissues. During the study period, 206 tissues from 200 patients with TS were included in the analysis. The culture positivity rates of vertebral bodies obtained by needle biopsy, paraspinal tissues obtained by needle biopsy, and tissues obtained by surgery were 69.0%, 85.3%, and 83.2%, respectively. Multivariate logistic regression identified that paraspinal tissues as biopsy sites were independently associated with mycobacterial culture positivity in TS undergoing needle biopsy (adjusted odds ratio, 3.68; 95% confidence interval: 1.13–11.99, P = 0.030). We demonstrated that the positivity rates of mycobacterial culture in TS were 69.0–85.3%. Paraspinal tissues as biopsy sites were significantly associated with culture positivity in needle biopsy, suggesting that targeting paraspinal tissues during needle biopsy may be the best method for diagnosing TS. [ABSTRACT FROM AUTHOR]

• A measles outbreak is occurring in South Korea despite high vaccine coverage. • Contact-adjusted immunity against measles is currently at 92%, increased from 86% in 2014. • There might be an option for catch-up campaigns to achieve herd immunity. • This is the first study to use contact patterns for understanding infectious disease outbreaks in South Korea. Measles has been reemerging in South Korea since December 2018 resulting in 185 cases by September 2019. We calculated contact-adjusted immunity levels against measles in South Korea using national seroprevalence data in 2014, vaccination uptake rates, and an age-specific contact matrix. We further explored options to achieve a contact-adjusted immunity level of 93% for herd immunity. The assessed contact-adjusted immunity level has increased from 86% in 2014 to 92% in 2018. Herd immunity could be achieved with immunizing 50% of susceptibles among birth cohorts 1999–2003 in 2018. Contact-adjusted immunity levels against measles have increased recently in South Korea, although they might not yet be high enough to guarantee herd immunity. [ABSTRACT FROM AUTHOR]

Aim: Panton–Valentine leukocidin (PVL) is a virulent cytotoxin and an indicator of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infection. In this study, we evaluated the prevalence and clinical and molecular characteristics of PVL-positive invasive S. aureus (ISA) infections in Korea. Results: A collection of 1,962 nonduplicate clinical isolates were screened for multilocus sequence typing, staphylococcal cassette chromosome mec (SCCmec), accessory gene regulator typing, major toxins, and antimicrobial susceptibility. Twenty-eight (1.4%) PVL-positive S. aureus samples were found; of them 19 (67.9%) were MRSA (8 CA and 11 healthcare-associated infections). Seventeen patients (60.7%) were men (median age: 63 years; range: 13–93 years) and 12 patients (42.9%) had no underlying comorbidities. The most common infections were skin and skin structure infection (SSSI) and pneumonia. The 30-day mortality rate was 37.0%. The most common PVL-positive MRSA clones were ST8-SCCmec IVa and ST30-SCCmec IVc along with their single-locus variants. Antimicrobial susceptibility and toxin-gene profile differed according to the clone. Conclusions: ISA infections caused by PVL-positive strains are rare in Korea, with the two most common infections being SSSI and pneumonia. Our findings indicated that several PVL-positive MRSA clones, predominantly ST8-SCCmecIVa and ST30-SCCmecIVc, were circulating and causing sporadic cases of ISA infections in the community and hospital settings. [ABSTRACT FROM AUTHOR]

The article focuses on description of the Middle East respiratory syndrome coronavirus (MERS-CoV) infection outbreak in South Korea. It states observation of changes in viral loads infections among patients of MERS with increment in mortality of patients. It mentions categorization of the MERS patients under illustration of severe diseases. It highlights on increment in prolonged viral shedding among patients along with respiratory secretions with absence of viral RNA detection.

Summary: Objectives: This study was performed to determine the incidence of herpes zoster and seroprevalence of varicella-zoster virus (VZV) in young adults of South Korea, where VZV seroprevalence remains relatively high. Methods: In South Korea, military service is compulsory for all healthy young men and hence those in military service might provide a reflection of the general population. The computerized database of the Armed Forces Medical Command was examined to identify the number of reported herpes zoster cases. In order to evaluate VZV seroprevalence, serum samples were obtained from randomly selected subjects among those who had been admitted to the Armed Forces Capital Hospital. Results: A total of 705 cases of herpes zoster were reported between June 2004 and May 2005. The annual incidence rate of herpes zoster was 141 (95% CI 131.0–151.8) per 100000 population. A total of 192 subjects were enrolled for the analysis of VZV seroprevalence. All subjects were male and their median age was 21 (range 19–24) years. The overall anti-VZV IgG seropositivity prevalence was 92.7% (178/192, 95% CI 88.0–95.7%). Conclusion: We have described a population-based study of the epidemiology of VZV infections in the military personnel of South Korea. [Copyright &y& Elsevier]