Changes in COVID‐19 measures in the workplace: 8‐month follow‐up in a cohort study of



The transmission of the novel coronavirus disease (COVID-19) has been spreading in Japan; the number of confirmed cases and deaths due to COVID-19 had increased to 472 112 and 9113, respectively, as of 31 March 2021 (Trends of Daily new confirmed COVID-19 cases in Japan shown in Figure 1).1 The declaration of the first state of emergency in April 2020 helped the Japanese government control the pandemic’s trajectory in Japan,2 and the state of emergency was lifted in late May 2020. Although several countries imposed strict lockdown measures to curb the spread of the disease, the measures in the declaration of a state of emergency in Japan lacked legal authority and depended on citizens’ self-restraint. The Japan Society for Occupational Health, in conjunction with the Japanese Society of Travel Medicine, published guidelines for preventive measures of COVID-19 in the workplace in June 2020 and made an addendum to the guideline on 11 August 2020: medium to long-term measures after business resumption (ie behavioural change including education for employees, environmental optimization, workstyle reform), prevention for workplace bullying and harassment related to COVID-19.3 The number of COVID-19 cases in Japan increased rapidly from the beginning of July to the beginning of August after the first emergency declaration was lifted, but it decreased after 7 August and did not increase rapidly again until late November.1 During this period, the Japanese government implemented a policy to resume economic activities, such as encouraging the population to eat at restaurants with its “Go to eat” campaign and engage in domestic travel through its “Go to travel” campaign.4 On 7 January 2021, Japan has declared its second state of emergency regarding COVID-19 in the capital, Tokyo, and three surrounding prefectures, as the number of daily infections surged and hospitals in Tokyo reported nearly 80% occupancy.5


Trends of daily new confirmed COVID-19 cases in Japan and each survey timing

Non-pharmaceutical interventions in the workplace, such as disinfection of the work environment and encouraging telework and telecommuting were reported as important preventive measures of COVID-19 and were expected to be implemented immediately in the pandemic.6, 7 During the 2009 influenza A (H1N1) pandemic, a randomized controlled trial reported that the adoption of combined workplace measures, including the measurements of body temperature each day and the obligation for symptomatic workers to stay at home, reduced the overall risk for infection transmission by 20% in the workplace.8 The guidelines of the United States Centers for Disease Control (CDC) suggested similar evidence-based appropriate workplace measures for COVID-19: conducting daily health checks up, encouraging of wearing masks, social distancing in the workplace.9 In an early phase of the pandemic in Japan, around the first state of emergency in April and May, our previous cross-sectional study revealed that about 80% of employees were under some workplace preventive measure.10 The proportion increased in May 2020, showing that most workplaces made an effort to establish preventive measures to respond to COVID-19 between March 2020 and May 2020.11

World Health Organization (WHO) reported an increasing attitude of apathy or resistance towards adherence to major non-pharmaceutical interventions as an expected and natural reaction to the prolonged nature of this crisis and the associated inconvenience and hardship, termed “pandemic fatigue”; there also was concern about the decline of workplace measures for COVID-19.12 For instance, A report of US residents showed a decrease in reported adherence to non-pharmaceutical interventions during the pandemic between April and November 2020.13 Workplace measures also were assumed to decrease during the pandemic, however, no long-term cohort study has been reported and the trend in the rate of implementation of workplace measures has not been quantified. Workplace measures relating to COVID-19 are important not only to prevent infection in the workplace, but also to prevent the spread of infection in the community.6 It is important to know how sustainable the workplace measures are that were implemented to prevent the transmission of COVID-19 in the workplace during repeated outbreaks, following our previous studies in the early phase of the outbreak.10, 11, 14

The aim of this study was to investigate the longitudinal change of implementation of preventive measures responding to COVID-19 in the workplace in Japan over repeated outbreaks, extending the follow-up to August and November 2020 when the second (in late July and August 2020) and third outbreaks (November 2020+) occurred.


2.1 Study design

The cohort was established from the panel of an Internet survey company, and included full-time employees aged 20-59 years old, living in Japan in February 2019. The sample was retrieved with an equal number of participants in each of eight cells stratified by gender and age (20-29, 30-39, 40-49, and 50-59). The cohort was composed of 4120 employees. The longitudinal analysis was conducted within that cohort, followed by online surveys.10, 11 The cohorts were invited to participate in the baseline survey of this study online on March 19-22, 2020 (T1). The respondents in T1, after excluding the unemployed, were invited to participate on May 22-26, 2020 (T2), about 1.5 months after the Japanese Cabinet office declared a state of emergency in response to COVID-19.2 The respondents in T2, after excluding the unemployed, were invited to participate on August 7-12 2020 (T3). The respondents in T3 were invited to participate in the follow-up survey on 6-12 November 2020 (T4).

This study protocol was approved by the research ethics committee of the graduate school of medicine/faculty of medicine, University of Tokyo (no. 10856-(2)(3)(4)(5)). The study conformed to the strengthening the reporting of observational studies in epidemiology (STROBE) guidelines.15

2.2 Participants recruitment

Participants of the study were a sample of full-time employees living in Japan, recruited from a database of over 500,000 workers created by an Internet survey company. We planned to recruit 1500 participants from 4120 respondents who participated in a previous survey in 2019 conducted by the Internet survey company.16 A total of 1448 (35.1%) participants completed an online questionnaire at T1 (March 2020). After excluding respondents who were unemployed (n = 27) at T1, we followed the remaining 1421 respondents and surveyed them at T2 (May 2020), T3 (August 2020), and T4 (November 2020). A total of 1032 (72.6%) participants completed the follow-up questionnaire at T2, excluding 389 non-respondents; we further excluded respondents who were unemployed (n = 17), on sick leave (n = 2), and on maternity leave (n = 17) at T2. Among the remaining 996 respondents who were followed further, 875 (87.9%) participants responded at T3, with 121 non-respondents; among them, 800 (91.4%) responded at T4, with 75 non-respondents (Figure 2). Reasons of non-responses were not assessed. We limited the analyses to data of these 800 respondents who completed all four surveys (follow-up rate to the initial 1441 employed respondents, 55.5%). Participants received a small token as a reward. The participants of the study were fully informed the aim, procedure, and ethical and privacy considerations, and informed consent was obtained.


Flowchart of participant recruitment

2.3 Measurements

2.3.1 Workplace measures to respond to COVID-19: preventive workplace measures

The list of measures taken in the workplace to respond to…


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