doi: medRxiv preprint NOTE: This preprint reports new research that has not been certified by peer review and should not be used to guide clinical practice.

ObjectiveThis open-label, non-randomized, phase I study examined the pharmacokinetics (PK) and radiation dosimetry of a single dose of radium-223 in Japanese patients with castration-resistant prostate cancer (CRPC) and bone metastases.MethodsSix male Japanese patients (mean age 72.5 years, range 65–79 years) with histologically or cytologically confirmed stage IV adenocarcinoma of the prostate were recruited. A single IV dose of radium-223 was delivered intravenously (IV) via slow bolus over a 2–5 min period: Cohort 1 received 50 kBq/kg and Cohort 2 received 100 kBq/kg.ResultsFollowing IV injection, radium-223 was rapidly eliminated from the blood in a multi-phasic manner. The fraction of the injected activity of radium-223 retained in the whole body 24 h following injection was 85 %. Biodistribution results showed initial bone uptake was 52 % (range 41–57 %). The maximum activity of radium-223 in the bone was observed within 2 h of dosing. Activity of radium-223 passed through the small intestine within 24 h. No activity was detected in other organs. The major radiation dose from radium-223 was found in osteogenic cells; calculated absorbed doses in osteogenic cells and in the red marrow were 0.76 Gy/MBq and 0.09 Gy/MBq, respectively.ConclusionsIn Japanese patients with CRPC and bone metastases, radium-223 (IV) achieved maximum activity in the bone rapidly and passed through the intestine within 24 h, without signs of activity in other organs. The PK profile and absorbed radiation dose in organs and tissues in Japanese patients were similar to data from non-Japanese patients.Trial registration identification: NCT01565746.

Gender differences in the determinants of willingness to get the COVID-19 vaccine among the working-age population in JapanMany factors are related to vaccination intentions. However, gender differences in the determinants of intention to get the coronavirus disease 2019 (COVID-19) vaccine have not been fully investigated. This study examined gender differences in the determinants of willingness to get the COVID-19 vaccine among the working-age population in Japan. We conducted a cross-sectional study of Japanese citizens aged 20-65 years using an online self-administered questionnaire in December 2020.Logistic regression analysis was performed. Among 27,036 participants (13,814 men and 13,222 women), the percentage who were willing to get the COVID-19 vaccine was lower among women than among men (33.0% vs. 41.8%). Age and education level showed a gender gap regarding the association with willingness to get the COVID-19 vaccine: men who were older or had a higher level of education were more willing to get the vaccine, whereas women aged 30-49 years and those with a higher level of education showed a relatively low willingness to get the vaccine. For both men and women, marriage, higher annual household income, underlying disease, current smoking, vaccination for influenza during the current season, and fear of COVID-19 transmission were linked to a higher likelihood of being willing to get the COVID-19 vaccine. These findings give important insight into identifying target groups in need of intervention regarding COVID-19 vaccination, especially among women.Providing education about COVID-19 and influenza vaccination in the workplace may be an effective strategy to increase COVID-19 vaccine uptake.

Objectives Little is known about workplace measures against coronavirus disease 2019 (COVID‐19) in Japan during the winter of 2020, especially in micro‐, small‐, and medium‐sized enterprises (MSMEs). This study aimed to provide an overview of the current situation of anti‐COVID‐19 measures in Japanese enterprises during the winter, considering company size. Methods This study was an Internet‐based nationwide cross‐sectional study. Individuals who were registered as full‐time workers were invited to participate in the survey. Data were collected using an online self‐administered questionnaire in December 2020. The chi‐squared test for trend was performed to calculate the P ‐value for trend for each workplace measure across company sizes. Results For the 27 036 participants, across company sizes, the most prevalent workplace measure was encouraging mask wearing at work, followed by requesting that employees refrain from going to work when ill and restricting work‐related social gatherings and entertainment. These measures were implemented by approximately 90% of large‐scale enterprises and by more than 40% of micro‐ and small‐scale enterprises. In contrast, encouraging remote working was implemented by less than half of large‐scale enterprises and by around 20% of micro‐ and small‐scale enterprises. There were statistically significant differences in all workplace measures by company size (all P < .001). Conclusions We found that various responses to COVID‐19 had been taken in workplaces. However, some measures, including remote working, were still not well‐implemented, especially in smaller enterprises. The findings suggest that occupational health support for MSMEs is urgently needed to mitigate the current wave of COVID‐19.

Objectives This study examined the relationship between the status of infection control efforts against COVID‐19 in the workplace and workers' mental health using a large‐scale Internet‐based study. Methods This cross‐sectional study was based on an Internet monitoring survey conducted during the third wave of the COVID‐19 epidemic in Japan. Of the 33 302 people who participated in the survey, 27 036 were included in the analyses. Participants answered whether or not each of 10 different infection control measures was in place at their workplace (eg, wearing masks at all times during working hours). A Kessler 6 (K6) score of ≥13 was defined as mild psychological distress. The odds ratios (ORs) of psychological distress associated with infection control measures at the workplace were estimated using a multilevel logistic model nested in the prefectures of residence. Results The OR of subjects working at facilities with 4 or 5 infection control measures for psychological distress was 1.19 (95% confidence interval [CI]: 1.05‐1.34, P = .010), that in facilities with 2 or 3 infection control measures was 1.43 (95% CI: 1.25‐1.64, P < .001), and that in facilities with 1 or no infection control measures was 1.87 (95% CI: 1.63‐2.14, P < .001) compared to subjects whose workplaces had ≥6 infection control measures. Conclusion Our findings suggest that proactive COVID‐19 infection control measures can influence the mental health of workers.