Trends in the Implementation of Workplace COVID-19 Measures in Japanese Companies: A One-Year Prospective Cohort Study.

This study evaluated trends in the implementation of workplace measures against COVID-19 by Japanese companies. We conducted a prospective cohort study, using data from December 2020 and December 2021, with 13,419 respondents participating in the follow-up survey. We evaluated nine workplace measures against COVID-19 (e.g., encouraging mask-wearing at work) and used the McNemar test and the Chi-square test for trend in the analysis. Small-sized companies (1-9 employees) exhibited a significant increase in the implementation of all the measures, with a rate of increase ranging from 8.4% to 16.1% (P-value: <0.001). Medium-sized companies (10-49 employees) also showed significant improvements in nearly all the measures (rate of increase: 3.5% to 10.5%, P-values: <0.001 to 0.004), except for one specific measure. Larger companies (more than 50 employees) displayed a mixed pattern, with some measures increasing and others decreasing. A persistent gap was observed between smaller (fewer than 50 employees) and larger companies in the implementation rates of these measures. The findings revealed a positive shift in workplace measures against COVID-19 among smaller companies in Japan over 1 year, although gaps between them and larger companies persisted.