Background Infection with SARS-CoV-2 has been shown to be highly protective against reinfection and symptomatic disease. However, effectiveness against the highly transmissible Delta variant and duration of natural immunity remain unknown. Methods This retrospective cohort study included 325,157 patients tested for coronavirus disease 2019 (COVID-19) via polymerase chain reaction (PCR) from 09 March 2020 to 31 December 2020 (Delta variant analysis) and 152,656 patients tested from 09 March 2020 to 30 August 2020 (long-term effectiveness analysis) with subsequent testing through 09 September 2021. The primary outcome was reinfection, defined as a positive PCR test >90 days after initial positive test. Results Among 325,157 patients tested before 31 December 2020, 50,327 (15.5%) tested positive. After 01 July 2021 (Delta dominant period), 40 (0.08%) of the initially positive and 1,494 (0.5%) of the initially negative patients tested positive. Protection of prior infection against reinfection with Delta was 85.4% (95% CI, 80.0-89.3). For the long-term effectiveness analysis, among 152,656 patients tested before 30 August 2020, 11,186 (7.3%) tested positive. After at least 90 days, 81 (0.7%) of the initially positive patients and 7,167 (5.1%) of the initially negative patients tested positive. Overall protection of previous infection was 85.7% (95% CI, 82.2-88.5) and lasted up to 13 months. Patients over age 65 had slightly lower protection. Conclusions SARS-CoV-2 infection is highly protective against reinfection with the Delta variant. Immunity from prior infection lasts for at least 13 months. Countries facing vaccine shortages should consider delaying vaccinations for previously infected patients to increase access.

Background: Venous thromboembolism (VTE) prophylaxis is recommended for hospitalized medical patients at high risk for VTE. Multiple risk assessment models exist, but few have been compared in large data sets. Methods: We constructed a derivation cohort using 6 years of data from 13 hospitals to identify risk factors associated with developing VTE within 14 days of admission. VTE was identified using a complex algorithm combining administrative codes and clinical data. We developed a multivariable prediction model and applied it to 2 validation cohorts: a temporal cohort, including two additional years and a cross-validation, in which we refit the model excluding one hospital at a time, and applied the refitted model to the holdout hospital. Performance was evaluated using the C-statistic. Results: The derivation cohort included 160,928 patients with a 14-day VTE rate of 0.79%. The final multivariable model contained 13 patient risk factors. The model had an optimism corrected C-statistic of 0.80 and good calibration. The temporal validation cohort included 55,301 patients, with a VTE rate of 0.74%. Based on the c-statistic, the Cleveland Clinic Model (CCM) outperformed the Padua model (0.76 vs. 0.72, p<0.01). The CCM was more sensitive (65.8% vs. 60.4%, p=0.05) and more specific (74.9% vs. 71.4%, p<.001), with higher positive (1.9% vs. 1.5%, p<.001) and negative predictive values (99.7% vs. 99.6%, p=0.01). C-statistics for the CCM at individual hospitals ranged from 0.64 to 0.76. Conclusion: A new VTE risk assessment model outperformed the Padua model. After further validation it could be recommended for widespread use.

This study investigates K-pop and K-pop fandom as an ongoing social movement. With popular South Korean group BTS as a case study, I examine how their fans join together and use collective action to create social change. My research answered three primary questions: (1) “How have K-pop fans been involved in societal causes prior to their recent surge in activism in 2020?,” (2) “To what extent does K-pop represent a social movement?,” and (3) “Do either K-pop music or the artists themselves contribute to fan participation in social advocacy, and if so, how?” I find that K-pop fans do constitute a social movement due to their use of extra-institutional tactics, based on John Fiske’s (1992) concept of fandom as “subversive by design,” Henry Jenkins’ (1992) participatory fan culture framework, and Social Movement Theory (King, 2011). I also further Yoon’s (2017) thesis that pop culture can give those who face a lack of resources and authority a means to challenge the status quo, emphasizing K-pop fans’ innovative use of social media mobilization. By explaining how K-pop and its fans can be understood as a social movement, my research rethinks how we consider K-pop fandom and at the same time encourages K-pop fans to continue their activism work and to expand further. Through a literature review and my own observations framed by theories, I conclude that K-pop fans demonstrate potential to be a powerful force for social change.

Background Previous infection with SARS-CoV-2 provides strong protection against future infection. There is limited evidence on whether such protection extends to the Omicron variant. Methods This retrospective cohort study included 635,341 patients tested for SARS-CoV-2 via polymerase chain reaction (PCR) from 09 March 2020 to 01 March 2022. Patients were analyzed according to the wave in which they were initially infected. The primary outcome was reinfection during the Omicron period (20 December 2021, to 01 March 2022). We used a multivariable model to assess the effects of prior infection and vaccination on hospitalization. Results Among the patients tested during the Omicron wave, 30.6% tested positive. Protection of prior infection against reinfection with Omicron ranged from 18.0% (95% confidence interval [CI], 13.0-22.7) for patients infected in wave 1 to 69.2% (95% CI, 63.4-74.1) for those infected in the Delta wave. In adjusted models, previous infection reduced hospitalization by 28.5% (95% CI, 19.1-36.7), while full vaccination plus a booster reduced it by 59.2% (95% CI, 54.8-63.1).

Pneumonia is a leading cause of hospitalization and death due to infection worldwide. Streptococcus pneumoniae and Legionella pneumophila remain among the most commonly identified bacterial pathogens. Unfortunately, more than half of all pneumonia cases today lack an etiologic diagnosis due to limitations in traditional microbiological methods like blood and sputum cultures, which are affected by poor sample collection, prior antibiotic administration, and delayed processing. Urinary antigen tests (UATs) for S. pneumoniae and L. pneumophila have emerged as powerful tools for improving the diagnosis of bacterial respiratory infections, enabling physicians to administer early directed therapy and improve antimicrobial stewardship. UATs are simple, rapid, and non-invasive diagnostic tests with high specificity (>90%) and moderate sensitivity (<80%). The potential impact of urinary antigen testing is especially significant for respiratory infections caused by Legionella . While all recommended community-acquired pneumonia (CAP) therapies are adequate for treating pneumococcal pneumonia, only certain antibiotics are effective against Legionella . Delayed therapy for Legionella is associated with worse clinical outcomes, which underscores the importance of rapid diagnostic methods like UATs. Despite their potential impact, current American Thoracic Society and Infectious Diseases Society of America (ATS/IDSA) guidelines argue against the routine use of urinary antigen testing for S. pneumoniae and L. pneumophila , except in patients with severe CAP and those with epidemiological risk factors for Legionella . Further research is necessary to evaluate the impact of early targeted treatment due to positive UAT results, as well as optimal strategies for UAT utilization. The purpose of this review is to summarize the UATs available for bacterial respiratory infections, describe current guidelines on their usage, and assess their impact on clinical outcomes and targeted therapy.

Background SARS-CoV-2 immunity has declined with subsequent waves and accrual of viral mutations. In vitro studies raise concern for immune escape by BA.4/BA.5, and a study in Qatar showed moderate protection, but these findings have yet to be reproduced. Methods This retrospective cohort study included individuals tested for COVID-19 by PCR during Delta or BA.1/BA.2 and retested during BA.4/BA.5. The preventable fraction (PF) was calculated as ratio of the infection/hospitalization rate for initially positive patients divided by infection/hospitalization rate for initially negative patients, stratified by age, and adjusted for age, gender, comorbidities, and vaccination using logistic regression. Results 20,987 patients met inclusion criteria. Prior Delta infection provided no protection against BA.4/BA.5 infection (Adjusted PF: 11.9% (95% confidence interval [CI], 0.8-21.8); p=0.036) and minimal protection against hospitalization (Adjusted PF: 10.7% (95%CI, 4.9-21.7); p=0.003). In adjusted models, prior BA.1/BA.2 infection provided 45.9% (95%CI, 36.2-54.1) (p &lt;0.001) protection against BA.4/BA.5 reinfection and 18.8% (95% CI, 10.3-28.3) (p&lt;0.0001) protection against hospitalization. Up-to-date vaccination provided modest protection against reinfection with BA.4/BA.5 and hospitalization. Conclusions Prior infection with BA.1/BA.2 and up-to-date vaccination provided modest protection against infection with BA.4/BA.5 and hospitalization, while prior Delta infection provided minimal protection against hospitalization, and no infection protection.

Background: SARS-CoV-2 immunity has declined with subsequent waves and accrual of viral mutations. In vitro studies raise concern for immune escape by BA.4/BA.5, and a study in Qatar showed moderate protection, but these findings have yet to be reproduced. Methods: This retrospective cohort study included individuals tested for COVID-19 by PCR during Delta or BA.1/BA.2 and retested during BA.4/BA.5. The preventable fraction (PF) was calculated as ratio of the infection/hospitalization rate for initially positive patients divided by infection/hospitalization rate for initially negative patients, stratified by age, and adjusted for age, gender, comorbidities, and vaccination using logistic regression. Results: 20,987 patients met inclusion criteria. Prior Delta infection provided no protection against BA.4/BA.5 infection (Adjusted PF: 11.9% (95% confidence interval [CI], 0.8-21.8); p=0.036) and minimal protection against hospitalization (Adjusted PF: 10.7% (95%CI, 4.9-21.7); p=0.003). In adjusted models, prior BA.1/BA.2 infection provided 45.9% (95%CI, 36.2-54.1) (p <0.001) protection against BA.4/BA.5 reinfection and 18.8% (95% CI, 10.3-28.3) (p<0.0001) protection against hospitalization. Up-to-date vaccination provided modest protection against reinfection with BA.4/BA.5 and hospitalization. Conclusions: Prior infection with BA.1/BA.2 and up-to-date vaccination provided modest protection against infection with BA.4/BA.5 and hospitalization, while prior Delta infection provided minimal protection against hospitalization, and no infection protection.

Background: Frontotemporal lobar degeneration (FTLD) refers to a group of neurodegenerative conditions, affecting the frontal and/or temporal lobes. Ongoing research has provided insight into developing clinical trials for FTLD and key clinical measures