Incidence of and risk factors for suspected COVID-19 reinfection in Kyoto City: a population-based epidemiological study.

To determine the clinical characteristics of and risk factors for suspected reinfection with coronavirus 2019 (COVID-19). This was a retrospective cohort study using population-based notification records of residents in Kyoto City (1.4 M) with laboratory-confirmed COVID-19 infection between 1 March 2020 and 15 April 2022. Reinfection was defined by two or more positive COVID-19 test results ≧ 90 days apart. Demographic characteristics, the route and timing of infection and history of vaccination were analysed to identify risk factors for reinfection. Among the cohort of 107,475 patients, reinfection was identified in 0.66% (n = 709). The age group with the highest reinfection rate was 18-39 years (1.06%), followed by 40-59 years (0.58%). Compared to the medical and nursing professionals, individuals who worked in the construction and manufacturing industry (odds ratio [OR]: 2.86; 95% confidence interval [CI]: 1.66-4.92) and hospitality industry (OR: 2.05; 95% CI: 1.28-.31) were more likely to be reinfected. Symptomatic cases at initial infection, receiving more than 2 doses of vaccination and risk factors for severe infection at initial infection were protective factors against reinfection. Of the reinfected individuals, the reinfection route was unknown in 65%. Reinfection with COVID-19 is uncommon, with suspected reinfections more likely in adults, those with high exposure and unvaccinated individuals; the reinfection route was unknown in the majority of cases. This study confirmed the need to continue with self-protection efforts and to implement vaccination programs in high-risk populations.

Multilocular thymic cyst detected during COVID­19 treatment in an HIV­positive adult man: A case report and literature review.

A multilocular thymic cyst (MTC) is a rare mediastinal tumor with multiloculated cyst-like structures in the anterior mediastinum. This tumfor is associated with inflammatory diseases, including human immunodeficiency virus (HIV) infection. The present study reports a case of MTC detected during coronavirus disease 2019 (COVID-19) treatment in an adult who was tested HIV positive. An anterior mediastinal tumor was incidentally detected on computed tomography in a 52-year-old man with a 20-year history of HIV infection on the 9th day of COVID-19. The patient was asymptomatic with no notable physical findings. Magnetic resonance imaging revealed a 28-mm bilocular cyst. Robot-assisted thoracoscopic tumor resection was performed. Pathological examination showed that the cyst was lined with squamous or cuboidal epithelium, and the cystic lesion wall was mainly composed of thymic tissue with follicular hyperplasia. Based on these findings, the patient was diagnosed with MTC. To date, only 15 MTC cases have been reported in patients with HIV, and the majority of cases showed HIV infection-related symptoms such as lymphoid interstitial pneumonia and parotid gland enlargement. The present case was atypical for an HIV-related MTC because it did not involve HIV infection-related symptoms, suggesting the possibility for an alternative etiology such as COVID-19. Further reports on MTC development in patients with COVID-19 are required to elucidate the relationship between MTC and COVID-19.

Clinical outcomes after tracheostomy in patients with coronavirus disease 2019: a single-center experience in Japan.

PURPOSE: Many patients with coronavirus disease 2019 require mechanical ventilation and tracheostomy. However, the timing and indications for tracheostomy are controversial. This study assessed 11 patients with coronavirus disease 2019 who underwent tracheostomy with clinical information and retrospective analyses. METHODS: A single-center retrospective observational study was performed on patients with coronavirus disease 2019 who underwent tracheostomy between 2020 and 2021. RESULTS: Failure to wean was the most common indication for tracheostomy, followed by extracorporeal membrane oxygenation decannulation and the need for secretion management. After tracheostomy, six patients (54.5%) were liberated from the ventilator. The time from intubation to tracheostomy (21.1 ± 9.14 days) was correlated with the duration of ventilator dependency (36.83 ± 20.45 days, r2 = 0.792, p = 0.018). The mean Acute Physiological and Chronic Health Evaluation II score was significantly lower in the ventilator-liberated group (23 ± 2.77) than in the non-ventilator-liberated group (31 ± 6.13, p = 0.0292). Furthermore, patients with Acute Physiological and Chronic Health Evaluation II scores of < 27 points achieved ventilator liberation and a long-term survival (p = 0.0006). CONCLUSIONS: This study describes the outcomes of a cohort of patients who underwent tracheostomy after intubation for coronavirus disease 2019. The Acute Physiological and Chronic Health Evaluation II score predicted whether or not the patient could achieve ventilator liberation.

High mortality and morbidity among vaccinated residents infected with the SARS-CoV-2 Omicron variant during an outbreak in a nursing home in Kyoto City, Japan.

BACKGROUND: Outbreaks of coronavirus disease 2019 (COVID-19) in long-term care facilities are associated with mortality, although vaccination have contributed to improvements. This study reports clinical impacts of a COVID-19 outbreak in a nursing home for elderly individuals in Kyoto City, Japan. METHODS: We performed epidemiologic and molecular investigations of the outbreak and characterized outcomes of the nursing home residents. RESULTS: During the outbreak period, a total of 31 residents (39.2%) and 26 staff members (49.1%) were infected with COVID-19. All residents and staff received two doses of a vaccine approximately 7 months prior. Ten residents with severe hypoxemia could not be transferred to a hospital due to a shortage of beds for COVID-19 patients. Within 90 days of the onset of the outbreak, 8 residents with COVID-19 (25.8%) died. A total of 48.4% of residents with COVID-19 developed 1 or more comorbidities. Viral genome analysis showed that the outbreak was caused by the Omicron BA.1.1.2 variant. CONCLUSIONS: Despite vaccination, high mortality and morbidity were observed in the COVID-19 outbreak due to the Omicron variant. Limiting medical care for residents with COVID-19 in facilities that experience ongoing outbreaks may be needed to reduce the risk of mortality among nursing home residents.

Transmissibility of SARS-CoV-2 B.1.1.214 and Alpha Variants during 4 COVID-19 Waves, Kyoto, Japan, January 2020-June 2021.

Household transmission is a primary source of SARS-CoV-2 spread. We used COVID-19 epidemiologic investigation data and viral genome analysis data collected in the city of Kyoto, Japan, during January 2020-June 2021 to evaluate the effects of different settings and viral strains on SARS-CoV-2 transmission. Epidemiologic investigations of 5,061 COVID-19 cases found that the most common category for close contact was within households (35.3%); this category also had the highest reverse transcription PCR positivity. The prevalent viral lineage shifted from B.1.1.214 in the third wave to the Alpha variant in the fourth wave. The proportion of secondary cases associated with households also increased from the third to fourth waves (27% vs. 29%). Among 564 contacts from 206 households, Alpha variant was significantly associated with household transmission (odds ratio 1.52, 95% CI 1.06-2.18) compared with B.1.1.214. Public health interventions targeting household contacts and specific variants could help control SARS-CoV-2 transmission.

Analysis of a city-wide COVID-19 prevention strategy for aged-care facilities during third and fifth waves of COVID-19 in Kyoto City, Kyoto, Japan.

BACKGROUND: During the third wave of the COVID-19 pandemic at the end of 2020, clusters occurred frequently in aged-care facilities (ACFs), which put pressure on the medical field in Japan. Based on this experience, Kyoto University and Kyoto City collaborated to promote a citywide COVID-19 prevention strategy to prevent the spread of COVID-19 within ACFs. The aim of this study was to clarify the effect of the prevention strategy among ACFs in Kyoto City during the third and fifth waves of the pandemic. METHODS: During the study period, the following measures were adopted as the prevention strategy in all ACFs: (1) active polymerase chain reaction (PCR) mass testing and facility-wide testing when a single case was identified, (2) implementation of strategies to prevent transmission within a facility, and (3) vaccination program for ACFs. RESULTS: Of the 1,144 facilities subjected to the mass testing, 71.0% participated in the whole program including active PCR testing. The remainder participated in the rest of the programs. The prevalence of ACF-related COVID-19 cases among total COVID-19 cases in Kyoto City decreased from 7.9% in the third wave to 4.1% in the fourth wave and 2.1% in the fifth wave. The incidence of clusters and proportion of severe elderly cases also decreased during the study period. CONCLUSIONS: A city-wide multidisciplinary effort including PCR mass testing and a vaccination program in cooperation with a university and local administrative office successfully reduced the clusters and transmission in ACFs in Kyoto City, Japan.