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"I feel perfectly fine and don't have a fever, but a precautionary antigen test came back positive." — In this scenario, can you go to work? While the judgment used to be "If there's no fever, it's fine," the rules in Japanese workplaces have changed significantly as of 2025.In conclusion, if you are Antigen or PCR positive, even if asymptomatic or without a fever, approximately 60% of working people in Japan—including those at large companies, civil service, and medical institutions—will be forced into a "minimum 7 days of home isolation."

When diagnosed with the flu, but only having a mild fever in the 37∘C range and light symptoms, or having a cough/runny nose but the fever has returned to normal, many people are unsure: "Is it okay to go to work with symptoms this mild?"However, in Japanese workplaces as of 2025, the decision to allow return to work is largely determined by the "Type of Workplace" rather than the "Severity of Symptoms."

When diagnosed with influenza, schools and workplaces require adherence to the home isolation rule of "5 days since onset + 2 days since fever subsided." The legal basis for this "rest period for the prevention of spread" is Article 18 of the Act on the Prevention of Infectious Diseases and Medical Care for Patients with Infectious Diseases, commonly known as the Infectious Disease Control Law (IDCL).This article stipulates the authority of the Prefectural Governor to issue a written notification to the patient (or their guardian) upon diagnosis of a disease classified as a "New Influenza or other infectious disease" (which includes influenza) to prevent the spread of infection.

It is an unfortunate reality that even when diagnosed with influenza and suffering from a high fever and poor physical condition, some companies still coerce employees into working due to reasons like "we are short-staffed" or "telework is not allowed." However, influenza is one of the few diseases where a "Law Stronger than the Company" exists.

When a long rest is required due to the flu, many people struggle with the decision: "Should I use my valuable paid annual leave, or should I take the Sickness and Injury Allowance (Shoˉbyoˉ Teate-kin) for 2/3 of my salary?" If both could be used together, the financial anxiety would be greatly alleviated.The conclusion is that while you absolutely cannot stack both benefits on the same day, it is possible to "combine" them by adjusting the timing or switching the paid leave retroactively.

When you have to miss nearly a week of work due to the flu, the most serious concern, alongside anxiety about return dates, is the economic impact of "Will my salary be zero?" If the company doesn't offer special leave or sufficient paid annual leave, many people brace for an "unpaid absence."However, influenza is a guaranteed condition for the Sickness and Injury Allowance (Shoˉbyoˉ Teate-kin) paid by health insurance. This is a vital safety net for workers that provides 2/3 (approx. 66.7%) of your standard daily remuneration if you are absent for 4 or more consecutive days, even after you have used up all your paid leave.

When diagnosed with the flu, alongside anxiety about days off and the return date, the financial anxiety about "What happens to my salary for a week of rest?" is a serious concern. Whether the time off is treated as "paid annual leave," "unpaid absence," or "special leave" uniquely defined by the company depends on the workplace rules.However, as of 2025, employee benefits in Japan have significantly improved. According to the survey results in this article, approximately 65-70% of working people in Japan can manage the flu using "Special Leave with 100% Salary."

After recovering from the flu, the most pressing concern is determining "When can I return to work?" While there is a desire to return quickly, rules to prevent the spread of infection are strictly defined based on occupation and company size.As of 2025, the rule that approximately 75% of workers in Japan follow—"5 days must pass since onset AND a full 2 days (48 hours) must pass since fever subsided"—has become the de facto national standard.

When you contract the flu, the most pressing concerns are"Exactly how many days will I have to take off?"and"What happen...

When you contract the flu, the "home isolation (suspension from work/school) period" varies strictly depending on your occupation and position. For schools, civil servants, and medical/caregiving sectors, there are clear legal/institutional rules of "5 days since onset + 2 days since fever subsides." However, for general company employees, especially those in Small and Medium-sized Enterprises (SMEs), these rules tend to be ambiguous.