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Assessing the impact of temperature on COVID-19 epidemiology is critical for implementing non-pharmaceutical interventions. However, few studies have accounted for the nature of contagious diseases, i.e., their dependent happenings. We aimed to quantify the impact of temperature on the transmissibility and virulence of COVID-19 in Tokyo, Japan, employing two epidemiological measurements of transmissibility and severity: the effective reproduction number ($$R_{t}$$ R t ) and case fatality risk (CFR). We estimated the $$R_{t}$$ R t and time-delay adjusted CFR and to subsequently assess the nonlinear and delayed effect of temperature on $$R_{t}$$ R t and time-delay adjusted CFR. For $$R_{t}$$ R t at low temperatures, the cumulative relative risk (RR) at the first temperature percentile (3.3 °C) was 1.3 (95% confidence interval (CI): 1.1–1.7). As for the virulence to humans, moderate cold temperatures were associated with higher CFR, and CFR also increased as the temperature rose. The cumulative RR at the 10th and 99th percentiles of temperature (5.8 °C and 30.8 °C) for CFR were 3.5 (95% CI: 1.3–10.0) and 6.4 (95% CI: 4.1–10.1). Our results suggest the importance to take precautions to avoid infection in both cold and warm seasons to avoid severe cases of COVID-19. The results and our proposed approach will also help in assessing the possible seasonal course of COVID-19 in the future.

The outbreak of monkeypox across non-endemic regions confirmed in May 2022 shows epidemiological features distinct from previously imported outbreaks, most notably its observed growth and predominance amongst men who have sex with men (MSM). We use a transmission model fitted to empirical sexual partnership data to show that the heavy-tailed sexual partnership distribution, in which a handful of individuals have disproportionately many partners, can explain the sustained growth of monkeypox among MSM despite the absence of such patterns previously. We suggest that the basic reproduction number (R0) for monkeypox over the MSM sexual network may be substantially above 1, which poses challenges to outbreak containment. Ensuring support and tailored messaging to facilitate prevention and early detection among MSM with high numbers of partners is warranted., Science, 378(6615), pp.90-94; 2022

COVID-19 vaccine effectiveness against death in Japan remains unknown. Furthermore, although evidence indicates that healthcare capacity influences case-fatality risk (CFR), it remains unknown whether this relationship is mediated by age. With a modeling study, we analyzed daily COVID-19 cases and deaths during January-August 2021 by using Tokyo surveillance data to jointly estimate COVID-19 vaccine effectiveness against death and age-specific CFR. We also examined daily healthcare operations to determine the association between healthcare burden and age-specific CFR. Among fully vaccinated patients, vaccine effectiveness against death was 88.6% among patients 60-69 years of age, 83.9% among patients 70-79 years of age, 83.5% among patients 80-89 years of age, and 77.7% among patients90 years of age. A positive association of several indicators of healthcare burden with CFR among patients70 years of age suggested an age-dependent effect of healthcare burden on CFR in Japan.

Background In Japan, a part of confirmed patients’ samples have been screened for the variant of concern (VOC), including the variant alpha with N501Y mutation. The present study aimed to estimate the actual number of cases with variant alpha and reconstruct the epidemiological dynamics. Methods The number of cases with variant alpha out of all PCR confirmed cases was estimated, employing a hypergeometric distribution. An exponential growth model was fitted to the growth data of variant alpha cases over fourteen weeks in Tokyo. Results The weekly incidence with variant alpha from 18–24 January 2021 was estimated at 4.2 (95% confidence interval (CI): 0.7, 44.0) cases. The expected incidence in early May ranged from 420–1120 cases per week, and the reproduction number of variant alpha was on the order of 1.5 even under the restriction of contact from January-March, 2021, Tokyo. Conclusions The variant alpha was predicted to swiftly dominate COVID-19 cases in Tokyo, and this has actually occurred by May 2021. Devising the proposed method, any country or location can interpret the virological sampling data.

The aim of this study is to clarify the details of distribution patterns of spinal epidural fluid and to establish it as measure of spontaneous intracranial hypotension (SIH) syndrome diagnosis. Magnetic resonance imaging findings of the spine were analyzed in 37 patients, 24 women and 13 men (mean age 46.3 years), with SIH. Detection rate, thickness and patterns of the fluid collection were evaluated at every vertebral level. Follow-up spinal MRI findings were also analyzed for changes in epidural fluid collection and association with clinical symptoms. The MR images of the cervical spine were obtained in 30 patients, the thoracic spine in 36, and the lumbar spine in 17 patients. Epidural fluid collection was detected totally in 36 patients (97%) and was predominantly found at the mid-thoracic vertebrae. The fluid tended to locate dorsal to the dural sac at the thoracic spine and ventral at the cervical and lumbar spine. Patients with shorter duration of illness tended to have thicker fluid in the thoracic spine. In follow-up MRI, the findings of epidural fluid collection has disappeared in 32/36 cases within 3 months after treatment. Although residual fluid collection was found at the thoracic level in 4 cases, clinical symptoms were improved in all patients. This study suggested that the mid-thoracic spine should be chosen as the target of MRI in screening of SIH, and enlarged dorsal epidural space is strongly indicative of SIH.

Objective Confirming the exact location of a fistula and the origins of draining veins during surgery for dural and perimedullary arteriovenous fistulas (AVFs) is crucial but sometimes inadequately performed, which can result in incomplete elimination of the lesion. Intraoperative digital subtraction angiography (DSA) is the gold standard for confirming the hemodynamics of an AVF; however, it cannot reveal the location of an AVF in the operative field. In this study, the efficacy of intraoperative intraarterial fluorescence video angiography during surgery for craniocervical junction dural and perimedullary AVFs was investigated. Methods We repeatedly employed this technology to evaluate its usefulness in revealing the flow dynamics and anatomy of AVFs and to confirm complete elimination of the fistula. Results Seven AVFs were included in this study. Their locations were C1 in 5 cases and C2 in 2 cases. Intraarterial fluorescence video angiography precisely revealed the locations of 3 dural AVFs, 1 perimedullary AVF, and 3 co-occurring dural and perimedullary AVFs. Frame-by-frame review of the fluorescence video angiography clearly demonstrated that fluorescence appeared earlier in the perimedullary AVF than in the draining vein through the dural AVF after intraarterial injection in all 3 co-occurring cases. Complete elimination of the AVF was also confirmed in all cases by fluorescence video angiography, as well as intraoperative and follow-up DSA. Conclusions Intraarterial fluorescence video angiography, particularly frame-by-frame review, enables surgeons to distinguish the flow dynamics of AVFs and contributes to the planning of effective surgical strategies for optimal results.

To assess the degree of hepatic fat content, simple and noninvasive methods with high objectivity and reproducibility are required. Magnetic resonance imaging (MRI) is one such candidate, although its accuracy remains unclear. We aimed to validate an MRI method for quantifying hepatic fat content by calibrating MRI reading with a phantom and comparing MRI measurements in human subjects with estimates of liver fat content in liver biopsy specimens. The MRI method was performed by a combination of MRI calibration using a phantom and double-echo chemical shift gradient-echo sequence (double-echo fast low-angle shot sequence) that has been widely used on a 1.5-T scanner. Liver fat content in patients with nonalcoholic fatty liver disease (NAFLD, n = 26) was derived from a calibration curve generated by scanning the phantom. Liver fat was also estimated by optical image analysis. The correlation between the MRI measurements and liver histology findings was examined prospectively. Magnetic resonance imaging measurements showed a strong correlation with liver fat content estimated from the results of light microscopic examination (correlation coefficient 0.91, P < 0.001) regardless of the degree of hepatic steatosis. Moreover, the severity of lobular inflammation or fibrosis did not influence the MRI measurements. This MRI method is simple and noninvasive, has excellent ability to quantify hepatic fat content even in NAFLD patients with mild steatosis or advanced fibrosis, and can be performed easily without special devices., Article, JOURNAL OF GASTROENTEROLOGY. 45(12):1263-1271 (2010)