Home · インフルエンザの出席停止

Flu Return-Date Calculator インフルエンザ出席停止の計算

By Dr. Masa · physician licensed in Japan · School Health and Safety Act Enforcement Regulations, Article 19

After flu, Japanese schools and nurseries count the days at home by a fixed rule: five days after the illness started, and two days after the fever went away — three days for kindergartens and nurseries. Enter the two dates and see the first day back under the rule.

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1School or nursery? 区分

Primary, junior high or high school小学校・中学校・高校Five days after onset + two days after the fever Kindergarten or nursery幼稚園・保育所Five days after onset + three days after the fever

2The two dates 発症日・解熱日

Each of these days counts as day 0; counting starts the next day. 発症日・解熱日はどちらも0日目として数えます。

Symptoms started 発症日 Fever went away 解熱日

Before you rely on the date ご注意

A doctor can allow an earlier return. Article 19 makes an exception when a school doctor or another physician judges, from the child's condition, that there is no risk of infection. 医師が感染のおそれがないと認めたときは、この限りではありません（施行規則第19条ただし書き）。
Some schools and nurseries want a form. Some ask for a parent's return form (登園届) or a doctor's note (意見書). Ask yours what it uses. 施設によって登園届・意見書を求めることがあります。
Public holidays are not included. Only Saturdays and Sundays are skipped when showing the next weekday. 祝日は含めていません。
What counts as "fever gone", and what happens if the fever comes back, are questions for your school or your doctor. For certified childcare centres (認定こども園), international schools and universities, ask which rule the institution follows.
Adults: seasonal flu is outside the work restrictions of the Infectious Diseases Control Act. Your employer's own rules may set a period off work. 大人: 季節性インフルエンザは感染症法の就業制限の対象外です。勤務先の規則で決まっていることがあります。
COVID-19 has a different rule (five days after onset, and one day after symptoms improve). This calculator is for seasonal flu only. 新型コロナウイルス感染症は別の規則です。

This tool counts the days in the rule. It does not diagnose flu, and it cannot tell you whether your child is well enough to go back. 規則にもとづく日数の計算で、診断ではありません。 If your child is unwell — a high fever that continues, difficulty breathing, or a change in how alert they are — see a doctor early. At night, see the after-hours care guide. For the shot, the 48-hour antiviral window and the rule itself, read our guide to flu season in Japan.