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Influenza alerts in Japan by prefecture

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Okinawa
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Prefectures with an advisory or warning (31)

Okinawa Warning2026-10-02
Kyoto Advisoryweek 44 · Nantan and Chutan-higashi health-centre areas
Ibaraki Advisoryweek 38
Ehime Advisory2026-11-06
Tochigi Advisory2026-11-05 · Kenpoku and Ansoku districts (health-centre areas)
Hyogo Advisory2026-11-05 · Himeji City, Kakogawa, Fukusaki, Akashi City, Takarazuka, Kato and Ako health-centre areas
Tokushima Advisory2026-11-05 · Miyoshi health-centre area
Fukushima Advisory2026-11-04
Aomori Advisory2026-10-29 · Sannohe/Hachinohe City, Seihoku and Kamikita health-centre areas
Yamanashi Advisory2026-10-29 · Chuhoku health-centre area
Hokkaido Advisory2026-10-15
Yamagata Advisory2026-10-15
Fukuoka Advisory2026-10-15
Iwate Advisory2026-10-14
Yamaguchi Advisory2026-10-14
Oita Advisory2026-10-14
Shizuoka Advisory2026-10-09
Hiroshima Advisory2026-10-08
Nagasaki Advisory2026-10-08
Kumamoto Advisory2026-10-08
Kagoshima Advisory2026-10-08
Ishikawa Advisory2026-10-07
Gifu Advisory2026-10-01
Kanagawa Advisory2026-09-28
Niigata Advisory2026-09-28
Aichi Advisory2026-09-28
Okayama Advisory2026-09-28
Saitama Advisory2026-09-25
Chiba Advisory2026-09-25
Toyama Advisory2026-09-25
Tokyo Advisory2026-09-17

Each prefecture in Japan decides for itself when to announce an influenza advisory or warning. This map shows the alerts the prefectures actually announced, with the date and a link to each announcement, together with the weekly number of cases per sentinel clinic from the Japan Institute for Health Security (JIHS). Japan's national "influenza level map" has been suspended since spring 2025.

What this map shows

The map colours show the advisories and warnings announced by each prefecture. When one covers only part of a prefecture, the list names the area.

Switch to “Cases” to colour the map by the weekly cases per sentinel site published by the Japan Institute for Health Security (JIHS). Use the week slider to see past weeks.

Switch to “Closures” to see the number of schools and other facilities closed, as announced by the Ministry of Health, Labour and Welfare.

The date of each announcement and a link to the prefecture's page are in the list and in the map pop-ups. Check the prefecture's announcement for details.

Questions and answers

What is the difference between an advisory and a warning?

Both are announced by each prefecture. An advisory means a large outbreak may be coming; a warning means a large outbreak is under way or continuing. Each prefecture sets its own criteria.

What does “cases per sentinel site” mean?

The number of influenza patients in a week at each of the clinics the prefecture has chosen to report (sentinel sites).

When is it updated?

The weekly figures are checked every day and updated when JIHS publishes them. Advisories and warnings are checked and updated every week.

Change log (version 1.1)

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