The True Story: Saitama's First School Closure of the Season

Saitama Prefecture in Japan announced on 16 September 2026 that a public junior high school in the south of the prefecture would close entirely, all 17 classes, on 16 and 17 September because 105 of its 509 students were absent with flu-like illness such as fever and cold symptoms.

It was the first flu school closure of the 2026 season in Saitama's public schools, with the season counted from 31 August 2026.

The Key Lesson: Clear Criteria Speed Up Decisions

Secondary schools in Thailand have hundreds to thousands of students who move between rooms by subject and share labs.

• Set absence thresholds in advance, such as the share of students absent with fever
• Close short and early rather than waiting for a school-wide outbreak
• Students change rooms by subject, spreading germs across many rooms
• Labs, computer rooms and music rooms share equipment
• The season can come early; Japan closed a school in September

How Flu Spreads

According to the World Health Organization, seasonal influenza spreads easily where people gather, such as schools and nursing homes. It spreads through droplets when people cough or sneeze, and through hands that touch contaminated surfaces and then the eyes, nose or mouth. Most people recover within a week, but young children, older adults, pregnant women and people with chronic illness are at risk of severe disease. Influenza is an enveloped virus, which suitable disinfectants can inactivate.

Risk Register for Secondary Schools

1. Mass absences at once: likelihood medium / impact high / level high. Mitigation: Class or school closure criteria and fogging during closure. Owner: Principal
2. Germs spread by room changes: likelihood high / impact medium / level high. Mitigation: Wipe desks each period and fog every room. Owner: Facilities
3. Shared computer rooms and labs: likelihood high / impact medium / level high. Mitigation: Wipe keyboards and equipment after every period. Owner: Room teacher
4. Indoor clubs and sports: likelihood medium / impact medium / level medium. Mitigation: Reduce closed-room activities during outbreaks. Owner: Student affairs
5. Midterm exams during the peak: likelihood medium / impact medium / level medium. Mitigation: Make-up exam plans for sick students. Owner: Assessment office

7 Steps to Manage Flu in Secondary Schools

1. Track absences by class daily against set thresholds
2. Close classes or the school briefly per criteria and health advice
3. Fog every room during closure, including labs and computer rooms
4. Wipe keyboards and lab equipment after every period
5. Ozone-treat sick bays and music rooms after school
6. Plan make-up exams so sick students do not push themselves
7. Tell parents the return-to-school criteria

How ULV Disinfection Fogging Helps

The World Health Disinfection disinfection service uses ULV fogging machines that turn the disinfectant into a fine mist. It settles across the whole area, including corners, curtains, upholstery and surfaces that hand wiping cannot reach.

• Whole-area coverage without relying on wiping spot by spot
• Quick return to use, typically about 30 minutes after fogging
• Uses Chemgene HLD4H, which meets EN 14476 for virucidal activity according to the product page
• The team wears full protective equipment, so owners and staff do not take the risk themselves
• Report and photos after the job for customers, management or authorities
• Tax invoice with 3% withholding tax for companies and agencies

Ozone Treatment for Closed Rooms and Stuffy Spaces

The World Health Disinfection ozone treatment service uses machines that generate ozone gas from oxygen in the air. It suits closed rooms such as meeting rooms, bedrooms, classrooms, sick bays and vans, helping reduce germs in the air and on surfaces and removing stale odours. Ozone breaks back down into oxygen after treatment, leaving no residue.

• Works alongside disinfection fogging: spray or wipe surfaces first, then use ozone for the air and corners of closed rooms
• No people or pets in the room during treatment: the team seals the room and runs a timer
• Ventilate after treatment before normal use resumes
• Machines tested by Intertek, according to WHD's service page
• Ideal after someone has been ill, such as recovered patients' rooms, shared bedrooms and shuttle vans

Before and After

Frequently Asked Questions

Q: Is a two-day closure enough time to fog? A: Yes, if booked ahead. The team works building by building, and areas are typically usable about 30 minutes after fogging.

Q: Can computer rooms be fogged? A: Tell the team so they can assess and plan around electronic equipment.

Q: Does the fogging disinfectant work on flu? A: The team uses Chemgene HLD4H, which meets EN 14476 for virucidal activity according to the product page, and influenza is an enveloped virus that suitable disinfectants can inactivate. Fogging does not replace vaccination or handwashing.

Q: Can I enter the room right after ozone treatment? A: No one should be in the room during treatment. Ventilate afterwards before normal use; the team will advise the right time for the room size.

Q: Can a public school get a tax invoice? A: Yes. Tax invoices are issued and 3% withholding tax is supported. Call 065-556-6294 or LINE @whd268.

Related Links and Sources

• World Health Disinfection disinfection service
• World Health Disinfection ozone treatment service
• Chemgene HLD4H disinfectant and price
• Influenza information from Thailand's Department of Disease Control, hotline 1422
• WHO seasonal influenza fact sheet

Prevent Flu with Disinfection Fogging and Ozone Treatment

Saitama shows clear criteria help schools close early and reopen safely. Reduce the risk with the World Health Disinfection disinfection service for classrooms, labs and canteens, and the ozone treatment service for sick bays and music rooms. To book, call 065-556-6294 or LINE @whd268.

Call 065-556-6294 | LINE: @whd268