Respiratory virus co-infections have been suggested to happen frequently and exacerbate patients’ conditions, but little is known about the detailed rates and the combinations of viruses during the COVID-19 pandemic period. A total of 255 symptomatic patients who underwent multiplex PCR tests were analyzed, and it was found that 6 (6/255=2.4%) patients were infected with multiple viruses. The patients ranged in age from 1 to 38 years, and one female patient was pregnant. Of the 6 patients, 4 had fever, and 5 had human rhinovirus/enterovirus and another virus. These data suggested that the rate of respiratory virus co-infection was low, and the combination of SAS-CoV-2 and other viruses was rare even during the COVID-19 pandemic.

The initial omicron SARS-CoV-2 subvariants, BA.1 and BA.2 (BA.1.2), were progressively displaced by BA.5in Japan in 2022. In the BA.5-dominant period, there were significantly more healthcare staff infected by nosocomial contact with persons with confirmed SARS-CoV-2 infection than those infected by household contact, compared with the BA.1.2-dominant period. The staff infected via nosocomial contact included non-patient-facing staff, in the BA.5-dominant period, although they did not become infected by SARS-CoV-2 through nosocomial contact in the BA.1.2-dominant period. These data suggest the importance of infection control and care for non-patient-facing staff, in the same way as for patient-facing staff.

Central line-associated bloodstream infections (CLABSIs) are important hospital-acquired infections that are related to increased mortality in cardiac intensive care units (CICUs). To determine the risk factors for CLABSIs, a case-control study was conducted in the CICU of our hospital. Emergency surgery (odds ratio: 9.6, 95% confidence interval: 1.633-56.926) was the strongest risk factor comparing the case group (n=11) to the control group (n=22). In addition, the indwelling period was significantly longer in the case group than in the control group (median 9 days versus 7 days, p=0.004). An intervention for the insertion of central lines was then started, with 1) thorough use of chlorhexidine-impregnated dressings (also known as chlorhexidine patches, CHG patches) in the insertion of central lines before emergency surgery, and 2) exchange of the central line 7 days after emergency surgery. After the intervention, the CLABSI incidence rate decreased from 6.8 to 0.8/1,000 device-days. These data suggest the usefulness of CHG patches and the importance of the early exchange of central lines in the CICU in patients following emergency surgery.

Background: COVID-19-related pneumonia was initially rare, though influenza-related pneumonia is well known as a severe complication of influenza. However, COVID-19-related pneumonia may be increasing since the omicron variant of COVID-19 appeared. Methods: The clinical differences between COVID-19-related and influenza-related pneumonia patients were retrospectively investigated in patients hospitalized from January 2022 to December 2023. Results: COVID-19-related and influenza-related pneumonias were found in 46 of 285 (15.8%) and 6 of 12 (50.0%) patients, respectively (p<0.001). Their mean ages were 75.5 (45-93) years and 53.8 (19-73) years in COVID-19-related and influenza-related pneumonia cases, respectively (p=0.002). Aspiration pneumonia was more common in COVID-19-related pneumonia (28/46=60.9%) than in influenza-related pneumonia patients, and it was treated by sulbactam/ampicillin (31/46=67.4%). The influenza-related pneumonia patients were more often infected in the work place (2/6=33.3%) and not vaccinated (4/6=66.7%), compared with COVID-19-related patients. Death occurred in 7 of 46 (15.2%) COVID-19 patients, but none of 6 influenza-infected patients died. Conclusions: These data suggest that COVID-19-related pneumonia presented as aspiration pneumonia in older patients, although influenza-related pneumonia was more common in younger and non-vaccinated patients and might be associated with immune mechanisms during the omicron variant surge era.