If you are in a hurry
- Children stay home from school “until 5 days have passed since onset and 2 days have passed since the fever went away (3 days for preschool-age children)”
- The day symptoms start and the day the fever goes away are both Day 0. Count the next day as Day 1, and your child can go back on the first day when both conditions are met
- For 2 days after the fever starts, watch for unusual behavior. If a seizure lasts 5 minutes or longer, or your child does not respond when called, call 119 (Japan’s emergency number)
Hello. I am Shunichi Gamo, MD, PhD, a board-certified pulmonologist and the director of Sendai Airport North Clinic.
Flu season is coming. After a child is diagnosed with influenza, the first thing parents usually want to know is this:
“The fever is gone, but when can my child go back to school (or nursery)?”
Let me give you the answer first. Children stay home from school “until 5 days have passed since onset and 2 days have passed since the fever went away (3 days for preschool-age children)”[1]. The key point is that the day symptoms start and the day the fever goes away are both counted as “Day 0.”
In this article I explain how to count the days, using calendar examples. I also cover the guideline for nurseries, how “certificates of recovery” are handled, what applies to adults at work, and what to watch for while recovering at home.
First, a note about our fever clinic on Sundays and holidays. PCR tests (tests that copy the virus’s genetic material so it can be detected) for influenza and COVID-19 give results the same day.
From October 4, 2026, our fever clinic is also open on Sundays and holidays
10:00 to 15:00 (no lunch break). No appointment is needed; you register by checking in on the day. We tell you the PCR result the same day. On Sundays and holidays we run the fever clinic only, with no general outpatient care and no IV drips. We are closed on Sunday, October 25. From November, we are generally open every Sunday and on holidays. Notice about the Sunday and holiday fever clinic
Shunichi Gamo, MD, PhD
Director, Sendai International Airport North Clinic
Born and raised locally, he attended Yuriage Elementary School and Yuriage Junior High School in Natori City. After graduating from Tohoku University School of Medicine, he worked at Sendai Open Hospital and Kesennuma City Hospital, and then at Tohoku University Hospital. In April 2021, in the middle of the COVID-19 pandemic, he opened Sendai International Airport North Clinic. Holding to a fever clinic that never turns patients away, he cared for well over 20,000 patients with fever in the two years before COVID-19 was moved to Class 5 under Japan’s infectious disease law.
Society memberships and board certifications
Certified Member and Board Certified Fellow, Japanese Society of Internal Medicine
Board Certified Pulmonologist, Japanese Respiratory Society
Board Certified Allergist, Japanese Society of Allergology
Board Certified Specialist, Japanese Society of Anti-Aging Medicine
PhD in Medicine (Tohoku University)
[Conclusion] Go back once both “5 days after onset” and “2 days after the fever goes away (3 days for preschoolers)” have been met
The rule on staying home from school for influenza (called “shusseki teishi,” meaning suspension of attendance) is set by a ministerial ordinance, the Enforcement Regulations of the School Health and Safety Act[1]. The wording is as follows.
“Until five days have passed since onset and two days have passed since the fever went away (three days for preschool-age children)”
In short, there are two conditions, and your child can go back to school from the day when both are met.
- [Condition 1] 5 days have passed since onset
Count the day symptoms started as Day 0. Days 1 to 5 are days off - [Condition 2] 2 days (3 days for preschoolers) have passed since the fever went away
Count the day the fever went away as Day 0. Days 1 to 2 are days off for school-age children, and Days 1 to 3 for preschoolers
“Preschool-age” here means children who have not yet started elementary school (kindergarten, nursery school, early childhood education centers, and so on). Elementary, junior high and high school students follow “2 days after the fever goes away,” and preschoolers follow “3 days after the fever goes away.”
The regulation also has a proviso: “this does not apply when the school doctor or another physician judges, based on the child’s condition, that there is no risk of infection”[1]. For influenza, however, it is fine to assume that you should simply stay home for the number of days above.
How to count the days off for influenza [the day symptoms start and the day the fever goes away are “Day 0”]
In fact, the way of counting the days is the easiest part to get wrong. The “Guidelines for Infectious Disease Control in Nursery Facilities,” issued by the Children and Families Agency (a national manual on how to respond), explain that the day symptoms start and the day the fever goes away are not counted, and the following day is Day 1[2].
- “Onset” generally means the day the fever started
- If influenza is diagnosed without a fever, the onset date is the day influenza-like symptoms such as cough, sore throat or tiredness began
- Saturdays, Sundays and holidays are counted as ordinary days
This explanation is written in the guidelines for nurseries, but it is based on the standard in the Enforcement Regulations of the School Health and Safety Act[2]. The same way of counting works for schools.
Calendar example 1: the fever goes away early
Here the fever starts on Monday and goes away on Wednesday.
| Day of the week | Days since onset | Days since the fever went away | Elementary school and older | Preschoolers (nursery or kindergarten) |
|---|---|---|---|---|
| Mon | Day 0 (onset) | – | Stay home | Stay home |
| Tue | Day 1 | – | Stay home | Stay home |
| Wed | Day 2 | Day 0 (fever gone) | Stay home | Stay home |
| Thu | Day 3 | Day 1 | Stay home | Stay home |
| Fri | Day 4 | Day 2 | Stay home | Stay home |
| Sat | Day 5 | Day 3 | Stay home | Stay home |
| Sun | Day 6 | Day 4 | OK | OK |
In this example the fever goes away early, but the “5 days after onset” condition is not yet met. So both groups can attend from Day 6 (Sunday). In practice, that means going back to school or nursery the next day, Monday.
Even if the fever goes away early, counting the day of onset as Day 0, your child cannot go back before Day 6. The same applies when an anti-influenza drug brings the fever down quickly.
Calendar example 2: the fever lasts longer
Here the fever starts on Monday and only goes away on Friday.
| Day of the week | Days since onset | Days since the fever went away | Elementary school and older | Preschoolers (nursery or kindergarten) |
|---|---|---|---|---|
| Mon | Day 0 (onset) | – | Stay home | Stay home |
| Tue | Day 1 | – | Stay home | Stay home |
| Wed | Day 2 | – | Stay home | Stay home |
| Thu | Day 3 | – | Stay home | Stay home |
| Fri | Day 4 | Day 0 (fever gone) | Stay home | Stay home |
| Sat | Day 5 | Day 1 | Stay home | Stay home |
| Sun | Day 6 | Day 2 | Stay home | Stay home |
| Mon | Day 7 | Day 3 | OK | Stay home |
| Tue | Day 8 | Day 4 | OK | OK |
In this example, the “2 days (3 days for preschoolers) after the fever goes away” condition is met later. So school-age children can go back on the Monday of the following week, and preschoolers on Tuesday.
As a rough rule, the earliest possible return is Day 6 from onset. If the fever lasts longer, it is Day 3 after the fever went away (Day 4 for preschoolers), with the day the fever went away as Day 0. Count both, and your child can go back on the later of the two days.
Time when a fever reducer is holding the fever down does not count as “fever gone”
The regulation does not say how to treat fever reducers (medicines that lower a fever)[1]. However, if a fever reducer has only lowered the temperature for a while, the fever can come back when the medicine wears off.
For that reason, the safe approach is to treat the day your child’s temperature stays normal without a fever reducer as the “day the fever went away.” The nursery guidelines also say it is preferable to keep a child home while a fever reducer is still being used[2].
Follow the rules of your school or nursery, such as the temperature record sheet, for what counts as a normal temperature. If a fever that had gone down comes back, it is safest to count again from the day it goes away the second time. If you are unsure, check with the school or nursery.
For nurseries, the guideline is “3 days after the fever goes away”
A nursery is not a school, so the Enforcement Regulations of the School Health and Safety Act do not apply to it directly. The “Guidelines for Infectious Disease Control in Nursery Facilities” mentioned above (Children and Families Agency, originally created by the Ministry of Health, Labour and Welfare) set the guideline for returning to nursery in line with the standard in those regulations[2].
The guideline for a child who has had influenza to return to nursery is “5 days have passed since onset and 3 days have passed since the fever went away (for infants and young children)”[2]. It is enough to remember it as “3 days after the fever goes away,” the same as for kindergarten children.
The guidelines say that how to handle a return to nursery should not be decided by each nursery on its own. It is important to decide it by talking with local medical institutions and the medical association, with support from the city or municipality[2]. For that reason, actual practice differs a little from area to area and from nursery to nursery.
Do you need a certificate of recovery or a permission slip to return? [It depends on the school or nursery]
According to the Q&A from the Ministry of Health, Labour and Welfare, when students who were absent with influenza or similar illnesses return to school, they do not need to submit a certificate of recovery or a negative test certificate[3]. There is also no need to be tested again.
On the other hand, some schools and nurseries ask for a “return notice” that a parent fills in, or an “opinion form” that a doctor fills in. The nursery guidelines also list influenza among the “infections for which a doctor may complete an opinion form.” They add, however, that opinion forms and return notices are not required across the board[2].
- First, check the school or nursery newsletter or contact book to see whether any documents are needed
- If a notice written by a parent is needed, it is easier to fill in if you have noted the onset date, the date the fever went away, and your child’s temperature each day
- If a document must be completed by a doctor, please bring it with you when you visit and ask us
Dr. GamoIf you are not sure which day your child can go back, try writing down the day symptoms started and the day the fever went away on a piece of paper. It greatly reduces counting mistakes.
Why “5 days after onset”? [Research on how long the influenza virus is shed]
According to the Q&A from the Ministry of Health, Labour and Welfare, influenza viruses are generally shed from the nose and throat from the day before onset until 3 to 7 days after onset[3]. The amount of virus falls once the fever goes away, but it is said to keep being shed after that.
There is a pooled analysis of “challenge studies,” in which healthy volunteers were deliberately given influenza virus (56 studies, 1,280 people)[4]. The amount of virus peaked on the second day after inoculation, and among 375 people the virus was shed for an average of 4.80 days (95% confidence interval 4.31 to 5.29 days)[4]. A confidence interval is the range in which the true value probably lies. This analysis did not include data on children or older adults[4].
What about children? In Nicaragua, a study followed 168 people who were the first in their household to fall ill, together with 668 household contacts[5]. The median number of days from onset until the virus was no longer shed was 3.1 days for ages 0 to 5, 2.3 days for ages 6 to 15, and 2.7 days for adults. The median is the middle value when the data are lined up in order. The virus was shed for the longest time after onset in young children aged 0 to 5.
There is also research from Japan. It looked at 28 children treated with an anti-influenza drug (laninamivir) during the 2011-2012 season[6]. When the fever went away, virus was found in 14.3 to 42.9% of children, depending on the virus type and the testing method[6]. From the third day after the fever went away and from the sixth day after onset, the figure was lower, at 0.0 to 19.0%[6].
In addition, a study in 13 clinics in 11 prefectures of Japan examined 518 people treated with anti-influenza drugs over 7 seasons, from 2013/2014 to 2019/2020[7]. In about 10 to 30% of those aged 6 to 18, viral genetic material was still found 5 days after onset in amounts that could still be infectious[7]. In those aged 0 to 5, the virus also declined more slowly.
In other words, even after the period of staying home ends, the ability to pass on the virus does not necessarily drop to zero. After your child goes back to school or nursery, wearing a non-woven surgical-type mask while coughing or sneezing continues is reassuring. The Q&A from the Ministry of Health, Labour and Welfare also recommends this as a courtesy to protect others[3].
When can adults go back to work after influenza? [There is no uniform legal rule]
The School Health and Safety Act is a law about children’s schools. For adults with influenza, there is no uniform legal number of days for returning to work as there is for schools. Please follow your employer’s work rules and company policy.
According to the Q&A from the Ministry of Health, Labour and Welfare, it is “not desirable, and not necessary” for a workplace to ask employees for a certificate of recovery or a negative test certificate[3]. For nursery staff such as childcare workers, the guidelines say that they may need to stop working in some cases, so please check the instructions of the nursery’s contracted doctor[2].
Even on a day when you are allowed to return to work, you may still be shedding the virus. Wear a mask while you have a cough or sneeze, and be especially careful around contact with small children, older adults and people with chronic illnesses.
What to watch for while recovering from influenza [unusual behavior and signs to see a doctor]
For 2 days after the fever starts, watch for unusual behavior
With influenza, unusual behavior can occur, such as suddenly running off, trying to dash out of a room, or wandering around[3]. It is said that this can happen whether or not an anti-influenza drug is taken, and regardless of the type of drug.
Serious unusual behavior that can lead to falls is reported more often in male minors of elementary school age and older (boys)[3]. It is also known to occur most often within 2 days after the fever starts. The Ministry of Health, Labour and Welfare urges families to take measures to prevent falls and other accidents for at least 2 days after the fever starts, whether or not a drug has been taken[3].
- Lock the front door and the windows of every room securely (use an auxiliary lock if you have one)
- Have your child sleep in a room that does not face a balcony
- If a room has a window with bars, have your child sleep there
- In a detached house, have your child sleep on the first floor if possible
Try to avoid leaving your child alone, even for short periods.
In these cases, please see a doctor
In the situations below, your child needs to be seen by a doctor regardless of the number of days off school. If a seizure lasts 5 minutes or longer, your child does not respond when called, or breathing looks very hard, call 119 (Japan’s emergency number) without hesitation.
- A seizure lasts 5 minutes or longer, repeats within a short time, or your child does not wake up properly after it stops (call 119)
- Your child does not respond when called, breathing looks very hard, or the lips look purplish (call 119)
- Strange words or actions do not settle, or your child is limp and slow to respond (go to an emergency department even at night)
- Your child cannot take any fluids and has not passed urine for half a day or more (go to an emergency department even at night)
Also, if a fever that had gone down comes back up, or the cough is getting worse, it may be a complication such as an ear infection (otitis media) or pneumonia (a complication is another illness that follows the original one). If there are none of the danger signs above at night, please see a doctor the next day.
If you are unsure what to do for your child at night or on a holiday, you can also use the children’s medical phone consultation line (#8000, a national consultation number for children’s health).
If you think it might be influenza, come to our fever clinic
The days off school are counted from “the day symptoms started,” so it is important to record exactly when the fever began. Anti-influenza drugs are said to be expected to work when they are started within 48 hours after symptoms appear[3]. If you have a fever, please consult the fever clinic early.
Our clinic has a policy of not refusing anyone who wants to come to the fever clinic (depending on the symptoms, we may direct you to a more suitable medical institution). We also see small children with fever.
| Day | Hours |
|---|---|
| Mon, Tue, Wed, Fri, Sat | 9:00 to 12:00 / 14:00 to 18:00 |
| Sundays and holidays (from October 4, 2026) | 10:00 to 15:00 (no lunch break, fever clinic only) |
| Thursday | Closed |
On Sundays and holidays we are open from 10:00 to 15:00. We are closed on Sunday, October 25, and from November we are generally open every Sunday and on holidays. On Sundays and holidays we run only the fever clinic, with no general outpatient care and no IV drips. For details, please see the Notice about the Sunday and holiday fever clinic.
How a visit works (no appointment needed)
You register by checking in on the day, using the QR code at the fever clinic entrance (a square pattern that you scan with your smartphone camera). When your turn is near, we call you by SMS (a text message sent to a mobile phone number) or by phone.
- Before you arrive, fill in the pre-visit questionnaire (optional; you can also fill it in when you check in at the entrance)
- Scan the QR code at the fever clinic entrance and check in by choosing “I have arrived, check me in” (required)
- On weekdays, once you have checked in, please wait in your car
- On Sundays and holidays, after you check in, we confirm your insurance card (My Number insurance card, certificate of eligibility, and so on) at the general outpatient entrance. Because general outpatient care is not offered on Sundays and holidays, please feel free to come in. After the confirmation, please wait in your car or similar
- When your turn is near, we call you by SMS or phone. Press the intercom at the fever clinic entrance and tell us your name
Patients are generally seen in check-in order, but the order may change depending on how severe the symptoms are. For details, please see About the pre-visit questionnaire and same-day check-in for the fever clinic.
When you visit, please tell us the date and time the fever started, the highest temperature, and the time you gave a fever reducer. This also helps later when you count the days off school.
Frequently asked questions
- My child’s fever started on Monday and went away on Tuesday. When can my child go back to school?
-
Monday is Day 0 of onset, so 5 days after onset is Saturday. Two days after the fever went away is Thursday, but both conditions must be met. So your child can attend from Day 6, Sunday, and in practice goes back to school on Monday of the following week.
- If the fever goes down because of a fever reducer, does that day count as the “day the fever went away”?
-
The regulation does not say how to treat fever reducers, but if the fever has only been lowered for a while by a fever reducer, the safe approach is not to count it as the day the fever went away. The fever can come back when the medicine wears off. Count from the day your child’s temperature stays normal without a fever reducer.
- How many days should a child who goes to nursery stay home?
-
Under the nursery guidelines, the guideline for returning is “5 days have passed since onset and 3 days have passed since the fever went away (for infants and young children).” That is 1 day longer after the fever goes away than for elementary school children and older. How documents are handled differs by nursery, so please check with yours.
- Do I need to get a certificate of recovery or a permission slip from the hospital?
-
The Q&A from the Ministry of Health, Labour and Welfare says that a certificate of recovery or a negative test certificate is not needed to return to school. However, some schools and nurseries ask for a notice written by a parent or an opinion form from a doctor. First check with the school or nursery, and if a doctor must fill it in, please ask us when you visit.
- How many days should an adult stay home with influenza?
-
For adults going back to work, there is no uniform legal number of days as there is for schools, so you follow your employer’s work rules and company policy. Even when you can return, the virus may still be shed, so wear a mask while you have a cough.
Summary [For influenza, count days off from “Day 0,” and return on the later of the two days]
- Children stay home from school “until 5 days have passed since onset and 2 days have passed since the fever went away (3 days for preschool-age children)”
- The day symptoms start and the day the fever goes away are both Day 0. Count the next day as Day 1, and your child can go back on the first day when both conditions are met
- The guideline for nurseries is “5 days after onset and 3 days after the fever goes away,” and how documents are handled differs by municipality and by school or nursery
- The safe approach is not to count time when a fever reducer is holding the fever down as “fever gone”
- For adults at work there is no uniform legal rule, so follow your employer’s regulations
- For 2 days after the fever starts, watch for unusual behavior. If a seizure lasts 5 minutes or longer, or your child does not respond when called, call 119 (Japan’s emergency number)
Counting the days is quite confusing until you get used to it. Just note down two things: the day symptoms started and the day the fever went away. If you have a fever and think “it might be influenza,” please leave the medical side to us.
That’s all.
Disclaimer
This article is intended to provide general medical information and does not replace an examination, diagnosis or treatment by a doctor. The content is based on medical knowledge at the time of publication, but the right approach differs from person to person. If you are worried about your symptoms, please consult a medical institution.
References
- Ministry of Education. Enforcement Regulations of the School Health and Safety Act (Ministry of Education Ordinance No. 18 of 1958), Articles 18 and 19 (in Japanese). e-Gov Law Search. Accessed October 2026. https://laws.e-gov.go.jp/law/333M50000080018
- Children and Families Agency. Guidelines for Infectious Disease Control in Nursery Facilities (2018 revision, partially revised in May 2023 and partially corrected in October 2023) (in Japanese). Children and Families Agency. 2023. https://www.mhlw.go.jp/content/10900000/20231010_policies_hoiku_25.pdf
- Ministry of Health, Labour and Welfare. Q&A on Comprehensive Measures against Acute Respiratory Infections (ARI), Fiscal Year 2025 (version of December 19, 2025) (in Japanese). Ministry of Health, Labour and Welfare website. Accessed October 2026. https://www.mhlw.go.jp/stf/seisakunitsuite/bunya/kenkou_iryou/kenkou/kekkaku-kansenshou/infulenza/QA2025.html
- Carrat F, Vergu E, Ferguson NM, Lemaitre M, Cauchemez S, Leach S, et al. Time lines of infection and disease in human influenza: a review of volunteer challenge studies. Am J Epidemiol. 2008 Apr;167(7):775-85. doi:10.1093/aje/kwm375 PMID: 18230677
- Ng S, Lopez R, Kuan G, Gresh L, Balmaseda A, Harris E, et al. The Timeline of Influenza Virus Shedding in Children and Adults in a Household Transmission Study of Influenza in Managua, Nicaragua. Pediatr Infect Dis J. 2016 May;35(5):583-6. doi:10.1097/INF.0000000000001083 PMID: 26910589
- Kondo H, Shobugawa Y, Hibino A, Yagami R, Dapat C, Okazaki M, et al. Influenza Virus Shedding in Laninamivir-Treated Children upon Returning to School. Tohoku J Exp Med. 2016 Feb;238(2):113-21. doi:10.1620/tjem.238.113 PMID: 26806610
- Li J, Wagatsuma K, Sun Y, Sato I, Kawashima T, Saito T, et al. Factors associated with viral RNA shedding and evaluation of potential viral infectivity at returning to school in influenza outpatients after treatment with baloxavir marboxil and neuraminidase inhibitors during 2013/2014-2019/2020 seasons in Japan: an observational study. BMC Infect Dis. 2023 Mar;23(1):188. doi:10.1186/s12879-023-08140-z PMID: 36991360
Related articles to read when you have a fever
For the Sunday and holiday fever clinic, see the Notice about the Sunday and holiday fever clinic. For how to come in, see About the pre-visit questionnaire and same-day check-in for the fever clinic.
