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The actual implementation status of self-isolation among Japanese workers during the COVID-19 outbreak

Our take —

This study found that adherence to self-isolation measures among Japanese workers experiencing cold-like symptoms was low despite guidelines to self-isolate if ill. Availability of work-from-home options, paid sick leave, and home delivery options of groceries and other necessities are likely needed to increase the practice of self-isolation, particularly among working populations with mild disease.

Study design


Study population and setting

Since February 17, 2020, individuals experiencing cold-like symptoms are recommended by the Japanese Society of Travel and Health to self-isolate for 7 days after symptom onset. The authors investigated the practice of such self-isolation through an internet survey of 1,226 Japanese workers recruited by a Japanese Internet research service company. Study participants were asked (yes/no) if at any point they had experienced “cold-like symptoms” since February 17, 2020 and if yes, if they had maintained self-isolation. The survey also collected information regarding their employment and sociodemographic factors.

Summary of Main Findings

82 out of the 1,226 participants (6.7%) indicated having had cold-like symptoms between February 17 and the day they took the survey (May 12 to 17, 2020). Of the 82 individuals, only 14 (17.1%) maintained strict isolation, defined as not leaving their homes at all or exclusively leaving for hospital visits. Most of the individuals who did not maintain strict self-isolation left their homes to shop for groceries or other necessities (70.7%) or to go to work (62.2%). Inability to work from home (OR: 4.22, 95% CI: 1.02-17.43) or being a company’s employee (as opposed to being self-employed – OR: 25.81, 95% CI: 2.23-298.31) were both indicated as being statistically significant factors in breaking the 7-day self-isolation period.

Study Strengths

The study empirically assessed the efficacy of self-isolation measures and potential barriers to following isolation guidelines among a working population. Data on type of job, impact of self-isolation on employment prospects, and reasons for lack of self-isolation were collected.


Those who were unemployed, stay-at-home individuals, or students were excluded, limiting the generalizability of the findings. Cold-like symptoms are not necessarily indicative of COVID-19. Overall, sample size was limited. Of the 82 individuals experiencing cold-like symptoms, 24 (29.3%) indicated having violated their 7-day of self-isolation to go to “other places for different reasons”. Authors did not clarify what those other locations or reasons may be. Recall bias may also be an issue, given that the online study took place in May but participants were asked about their behaviour and their health since mid-February. Disease severity or symptom type was not assessed or correlated with propensity for self-isolation. In addition, as the authors note, study participants were recruited from a pool of individuals enrolled in a single Internet research company, potentially introducing selection bias and limiting generalizability of findings to the larger Japanese population. Only 6.7% (n=82) of the study population exhibited cold-like symptoms. Transmission of COVID-19 and isolation measures varied in the February – May, 2020 timeframe; the survey did not ask when participants experienced cold-like symptoms and subsequent self-isolation within this 3-month time frame, potentially neglecting confounding factors. Finally, authors note that the study population was recruited from a larger longitudinal study investigating personal protective measures during the COVID-19 pandemic, which may have altered the perception and implementation of participants’ self-isolation behaviour.

Value added

This study adds to the very limited evidence base on the actual practice of self-isolation among workers reporting cold-like symptoms following implementation of self-isolation guidelines to prevent COVID-19 transmission.

This review was posted on: 10 September 2020