Background/Aims: Since the coronavirus disease 2019 (COVID-19) outbreak, hospitals have implemented infection control measures to minimize the spread of the virus within facilities. This study aimed to investigate the impact of COVID-19 on the incidence of healthcare-associated infections (HCAIs) and common respiratory virus (cRV) infections in hematology units. Methods: This retrospective study included all patients hospitalized in Catholic Hematology Hospital between 2019 and 2020. Patients infected with vancomycin-resistant Enterococci (VRE), carbapenemase-producing Enterobacterales (CPE), Clostridium difficile infection (CDI), and cRV were analyzed. The incidence rate ratio (IRR) methods and interrupted time series analyses were performed to compare the incidence rates before and after the pandemic. Results: The incidence rates of CPE and VRE did not differ between the two periods. However, the incidence of CDI increased significantly (IRR: 1.41 [p = 0.002]) after the COVID-19 pandemic. The incidence of cRV infection decreased by 76% after the COVID-19 outbreak (IRR: 0.240 [p < 0.001]). The incidence of adenovirus, parainfluenza virus, and rhinovirus infection significantly decreased in the COVID-19 period (IRRs: 0.087 [p = 0.003], 0.031 [p < 0.001], and 0.149 [p < 0.001], respectively). Conclusions The implementation of COVID-19 infection control measures reduced the incidence of cRV infection. However, CDI increased significantly and incidence rates of CPE and VRE remained unchanged in hematological patients after the pandemic. Infection control measures suitable for each type of HCAI, such as stringent hand washing for CDI and enough isolation capacities, should be implemented and maintained in future pandemics, especially in immunocompromised patients.

Objective: To compare the outcomes of digital breast tomosynthesis (DBT) screening combined with ultrasound (US) with those of digital mammography (DM) combined with US in women with dense breasts. Materials and Methods: A retrospective database search identified consecutive asymptomatic women with dense breasts who underwent breast cancer screening with DBT or DM and whole-breast US simultaneously between June 2016 and July 2019. Women who underwent DBT + US (DBT cohort) and DM + US (DM cohort) were matched using 1:2 ratio according to mammographic density, age, menopausal status, hormone replacement therapy, and a family history of breast cancer. The cancer detection rate (CDR) per 1000 screening examinations, abnormal interpretation rate (AIR), sensitivity, and specificity were compared. Results: A total of 863 women in the DBT cohort were matched with 1726 women in the DM cohort (median age, 53 years; interquartile range, 40–78 years) and 26 breast cancers (9 in the DBT cohort and 17 in the DM cohort) were identified. The DBT and DM cohorts showed comparable CDR (10.4 [9 of 863; 95% confidence interval {CI}: 4.8–19.7] vs. 9.8 [17 of 1726;95% CI: 5.7–15.7] per 1000 examinations, respectively; P = 0.889). DBT cohort showed a higher AIR than the DM cohort (31.6% [273 of 863; 95% CI: 28.5%–34.9%] vs. 22.4% [387 of 1726; 95% CI: 20.5%–24.5%]; P < 0.001). The sensitivity for both cohorts was 100%. In women with negative findings on DBT or DM, supplemental US yielded similar CDRs in both DBT and DM cohorts (4.0 vs. 3.3 per 1000 examinations, respectively; P = 0.803) and higher AIR in the DBT cohort (24.8% [188 of 758; 95% CI: 21.8%–28.0%] vs. 16.9% [257 of 1516; 95% CI: 15.1%–18.9%; P < 0.001). Conclusion DBT screening combined with US showed comparable CDR but lower specificity than DM screening combined with US in women with dense breasts.

OBJECTIVES: We estimated the population prevalence of antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), including unreported infections, through a Korea Seroprevalence Study of Monitoring of SARS-CoV-2 Antibody Retention and Transmission (K-SEROSMART) in 258 communities throughout Korea. METHODS: In August 2022, a survey was conducted among 10,000 household members aged 5 years and older, in households selected through two stage probability random sampling. During face-to-face household interviews, participants self-reported their health status, COVID-19 diagnosis and vaccination history, and general characteristics. Subsequently, participants visited a community health center or medical clinic for blood sampling. Blood samples were analyzed for the presence of antibodies to spike proteins (anti-S) and antibodies to nucleocapsid proteins (anti-N) SARS-CoV-2 proteins using an electrochemiluminescence immunoassay. To estimate the population prevalence, the PROC SURVEYMEANS statistical procedure was employed, with weighting to reflect demographic data from July 2022. RESULTS: In total, 9,945 individuals from 5,041 households were surveyed across 258 communities, representing all basic local governments in Korea. The overall population-adjusted prevalence rates of anti-S and anti-N were 97.6% and 57.1%, respectively. Since the Korea Disease Control and Prevention Agency has reported a cumulative incidence of confirmed cases of 37.8% through July 31, 2022, the proportion of unreported infections among all COVID-19 infection was suggested to be 33.9%. CONCLUSIONS The K-SEROSMART represents the first nationwide, community-based seroepidemiologic survey of COVID-19, confirming that most individuals possess antibodies to SARS-CoV-2 and that a significant number of unreported cases existed. Furthermore, this study lays the foundation for a surveillance system to continuously monitor transmission at the community level and the response to COVID-19.

This study aimed to investigate the association between Bacille Calmette-Guérin (BCG) vaccination and nontuberculous mycobacterial pulmonary disease (NTM-PD). Patients in the prospective NTM-PD cohort were matched to healthy controls to measure the association between BCG and NTM-PD development. The clinical course of NTM-PD patients was also evaluated to investigate the association between BCG and NTM-PD progression. BCG scars were not associated with NTM-PD development (adjusted odds ratio [OR], 2.04; 95% confidence interval [CI], 0.96–4.34) or progression (adjusted OR, 1.61; 95% CI, 0.92–2.81).In conclusion, BCG vaccination was not associated with the development or progression of NTM-PD.

A 60-year-old man diagnosed with unresectable hepatocellular carcinoma (HCC) presented to the hospital with pain in the perineal region. He had been taking lenvatinib every day for 2 months after he was diagnosed with HCC with metastases to the lymph node, small bowel mesentery, and retroperitoneal space. Enhanced abdominal computed tomography revealed mild elevation in intensity in the perineal subcutaneous tissue with subcutaneous emphysema. The patient was diagnosed with Common Terminology Criteria for Adverse Events grade 3, skin ulceration of stage IV with full-thickness skin loss and tissue necrosis in the muscular layer. The patient was taken off the medication with prescription of antibiotics, and after 3 weeks, the skin has fully recovered. This is the first report of an HCC patient who presented with a skin ulceration of stage IV after lenvatinib treatment. We recommend stopping the medication immediately and changing to alternative treatments with appropriate supportive care.

Background/Aims: Besifovir dipivoxil maleate (BSV), an acyclic nucleotide phosphonate, shows potent antiviral activity against hepatitis B virus. Our previous 48-week trial revealed that BSV has comparable antiviral efficacy to tenofovir disoproxil fumarate (TDF) and better safety profiles in terms of improved renal and bone safety. This extension study evaluated the prolonged efficacy and safety of BSV in treatment-naive chronic hepatitis B patients. Methods: Patients continued to participate in an open-label BSV study after an initial 48-week double-blind comparison of BSV and TDF treatment. The antiviral efficacy and drug safety was evaluated up to 192 weeks in two groups: patients continuing BSV treatment (BSV-BSV) and patients switching from TDF to BSV after 48 weeks (TDF-BSV). Results: Among 197 patients receiving randomized treatments, 170 (86%) entered the open-label phase and 152 (77%) entered the 192-week extension study. Virological response rates over 192 weeks were 92.50% and 93.06% in the BSV-BSV and TDF-BSV groups, respectively (P=0.90). Hepatitis B envelop antigen seroconversion and alanine aminotransferase normalization rates were similar between the groups (P=0.75 and P=0.36, respectively). There were no drug-resistant mutations to BSV. Bone mineral density and renal function were well preserved in the BSV-BSV group, whereas these initially worsened then recovered after switching therapy in the TDF-BSV group. Conclusions BSV maintained potent antiviral efficacy after 192 weeks and showed no evidence of drug resistance. BSV was safe, well tolerated, and effective in patients who switched from TDF to BSV. Trial Registration Number: NCT01937806 (date: 10 Sep 2013).

Background/Aims: Besifovir dipivoxil maleate (BSV), an acyclic nucleotide phosphonate, shows potent antiviral activity against hepatitis B virus. Our previous 48-week trial revealed that BSV has comparable antiviral efficacy to tenofovir disoproxil fumarate (TDF) and better safety profiles in terms of improved renal and bone safety. This extension study evaluated the prolonged efficacy and safety of BSV in treatment-naive chronic hepatitis B patients. Methods: Patients continued to participate in an open-label BSV study after an initial 48-week double-blind comparison of BSV and TDF treatment. The antiviral efficacy and drug safety was evaluated up to 192 weeks in two groups: patients continuing BSV treatment (BSV-BSV) and patients switching from TDF to BSV after 48 weeks (TDF-BSV). Results: Among 197 patients receiving randomized treatments, 170 (86%) entered the open-label phase and 152 (77%) entered the 192-week extension study. Virological response rates over 192 weeks were 92.50% and 93.06% in the BSV-BSV and TDF-BSV groups, respectively (P=0.90). Hepatitis B envelop antigen seroconversion and alanine aminotransferase normalization rates were similar between the groups (P=0.75 and P=0.36, respectively). There were no drug-resistant mutations to BSV. Bone mineral density and renal function were well preserved in the BSV-BSV group, whereas these initially worsened then recovered after switching therapy in the TDF-BSV group. Conclusions BSV maintained potent antiviral efficacy after 192 weeks and showed no evidence of drug resistance. BSV was safe, well tolerated, and effective in patients who switched from TDF to BSV. Trial Registration Number: NCT01937806 (date: 10 Sep 2013).

A 60-year-old man diagnosed with unresectable hepatocellular carcinoma (HCC) presented to the hospital with pain in the perineal region. He had been taking lenvatinib every day for 2 months after he was diagnosed with HCC with metastases to the lymph node, small bowel mesentery, and retroperitoneal space. Enhanced abdominal computed tomography revealed mild elevation in intensity in the perineal subcutaneous tissue with subcutaneous emphysema. The patient was diagnosed with Common Terminology Criteria for Adverse Events grade 3, skin ulceration of stage IV with full-thickness skin loss and tissue necrosis in the muscular layer. The patient was taken off the medication with prescription of antibiotics, and after 3 weeks, the skin has fully recovered. This is the first report of an HCC patient who presented with a skin ulceration of stage IV after lenvatinib treatment. We recommend stopping the medication immediately and changing to alternative treatments with appropriate supportive care.

Background/Aims: To improve the eradication rate of a first-line therapy for Helicobacter pylori infection, alternate regimens such as sequential, concomitant, and hybrid therapies have been tried. The aim of this study was to evaluate the eradication rate of the 10-day hybrid therapy as a first-line therapy. Materials and Methods: This retrospective study enrolled 124 patients from the Korea University Ansan Hospital between April 2016 and December 2019. The 10-day hybrid therapy comprised 5 days of dual therapy (proton pump inhibitor [PPI] standard dose and amoxicillin 1 g, twice daily) followed by 5 days of quadruple therapy (PPI, amoxicillin 1 g, clarithromycin 500 mg, and metronidazole 500 mg, twice daily). We compared the 10-day hybrid therapy with the 10-day concomitant therapy comprising PPI, amoxicillin 1 g, clarithromycin 500 mg, and metronidazole 500 mg, twice daily. Eradication was assessed by a 13C-urea breath test or gastroscopic biopsy at least 4 weeks after treatment completion. Results: The eradication rates of the 10-day hybrid and concomitant therapies were 74.2% (46/62) and 67.7% (42/62), respectively, in the intention-to-treat (ITT) analysis and 88.5% (46/52) and 82.4% (42/51), respectively, in the per-protocol (PP) analysis. There was no significant difference in the eradication rates between the two groups in the ITT (P=0.429) and PP analysis (P=0.380). Adverse events developed in 75.0% and 70.6% of patients in the hybrid and concomitant groups, respectively, but there was no significant difference (P=0.615). Conclusions The 10-day hybrid therapy can be an option for a first-line therapy of Helicobacter pylori infection.

Background/Aims: To improve the eradication rate of a first-line therapy for Helicobacter pylori infection, alternate regimens such as sequential, concomitant, and hybrid therapies have been tried. The aim of this study was to evaluate the eradication rate of the 10-day hybrid therapy as a first-line therapy. Materials and Methods: This retrospective study enrolled 124 patients from the Korea University Ansan Hospital between April 2016 and December 2019. The 10-day hybrid therapy comprised 5 days of dual therapy (proton pump inhibitor [PPI] standard dose and amoxicillin 1 g, twice daily) followed by 5 days of quadruple therapy (PPI, amoxicillin 1 g, clarithromycin 500 mg, and metronidazole 500 mg, twice daily). We compared the 10-day hybrid therapy with the 10-day concomitant therapy comprising PPI, amoxicillin 1 g, clarithromycin 500 mg, and metronidazole 500 mg, twice daily. Eradication was assessed by a 13C-urea breath test or gastroscopic biopsy at least 4 weeks after treatment completion. Results: The eradication rates of the 10-day hybrid and concomitant therapies were 74.2% (46/62) and 67.7% (42/62), respectively, in the intention-to-treat (ITT) analysis and 88.5% (46/52) and 82.4% (42/51), respectively, in the per-protocol (PP) analysis. There was no significant difference in the eradication rates between the two groups in the ITT (P=0.429) and PP analysis (P=0.380). Adverse events developed in 75.0% and 70.6% of patients in the hybrid and concomitant groups, respectively, but there was no significant difference (P=0.615). Conclusions The 10-day hybrid therapy can be an option for a first-line therapy of Helicobacter pylori infection.