Hand, foot and mouth disease and herpangina, epidemiological week 1–30, 2025 (as at July 30, 2025)

◆Hand, foot and mouth disease and herpangina, epidemiological week 1–30, 2025 (as at July 30, 2025)

Hand, foot and mouth disease (HFMD) and herpangina are infectious diseases caused by enterovirus infection that mainly affect infants and young children, with vesicular eruptions of the oral mucosa and fever as their main symptoms. Under Japan’s Infectious Diseases Control Law, both infectious diseases are classified as Category V pediatric sentinel surveillance diseases in the National Epidemiological Surveillance of Infectious Diseases (NESID). The number of clinically diagnosed patients was reported on a weekly basis from approximately 3,000 pediatric sentinel sites nationwide until April 6, 2025, and since April 7, 2025, from approximately 2,000 sentinel sites. For HFMD, patients with the following two clinical features are reported: “vesicles measuring approximately 2-5 mm appearing on the palms, soles or dorsum of the feet, and oral mucosa” and “vesicles that heal without forming scabs”. For herpangina, patients with the following two clinical features are reported: “sudden onset with high fever” and “vesicular eruptions, ulcers or redness around the uvula”. In general, the prognosis is good, but in some cases of HFMD, the illness becomes severe, and when infants or young children develop central nervous system complications, neurogenic pulmonary edema, or cardiopulmonary failure, death may occur. For both diseases, since the main routes of transmission are droplet and contact infection, thorough handwashing and proper disposal of excreta are important. The causative viruses of HFMD in Japan are enteroviruses such as coxsackievirus A6 (CA6), A16 (CA16), A10 (CA10), and enterovirus 71 (EV71). For herpangina, it is often caused mainly by group A coxsackieviruses, but coxsackievirus group B and echoviruses may also be causative viruses. For both HFMD and herpangina, treatment is generally limited to supportive care.

Both HFMD and herpangina are diseases that show increased activity every summer.Regarding trends in HFMD activity in epidemic years, in the past 10 years, excluding the years of the coronavirus disease 2019 (COVID-19) pandemic, nationwide trends showed an increase around week 20, reaching a peak at about 10.0 cases per sentinel site around week 30, then decreasing to about 1.0 around week 40, and almost subsiding by around weeks 48–50. In 2024, a characteristic feature was that, following the peak in week 28 (13.34 cases per sentinel site, 41,885 cases), another peak occurred in week 41 (10.78 cases per sentinel site, 33,760 cases) showing a bimodal pattern. Disease activity levels in 2025 have been lower than usual; although from week 20 an increase began with 0.13 cases per sentinel site (305 cases), the increase has been gradual, and was 0.59 (1,380 cases) even at week 30, with no large epidemic confirmed. (Graph of epidemic trends over the past 10 years: https://id-info.jihs.go.jp/surveillance/idwr/jp/graph/weekly/06hfmd.html)

Regarding trends in herpangina activity, excluding the years of the COVID-19 pandemic, an increase was confirmed around week 20, reaching a peak of about 3.0–4.0 cases per sentinel site around week 30, then decreasing relatively rapidly, and subsiding by around weeks 48–50.

The trend in herpangina reports in 2025 has been similar to that of previous years; from week 23, the number of cases per sentinel site began to increase with 0.19 (447 cases), rising to 1.02 (2,398 cases) in week 26, 1.87 (4,401 cases) in week 29, and 1.63 (3,852 cases) in week 30. The highest peak in the past 10 years was in week 27 of 2023 with 7.32 cases per sentinel site (22,980 cases), and the situation in 2025 is of a scale similar to or smaller than usual years. (Graph of epidemic trends over the past 10 years: https://id-info.jihs.go.jp/surveillance/idwr/jp/graph/weekly/10herp.html)

After the COVID-19 pandemic, irregular epidemic patterns have been confirmed for various infectious diseases. For HFMD in 2024, a bimodal pattern was seen, with the main virus detected being CA6 during the first peak and CA16 during the next peak (https://kansen-levelmap.mhlw.go.jp/Byogentai/Pdf/data115j.pdf). In 2025, the trends in disease activity have been generally similar to previous years, with no large epidemic observed. Nevertheless, continued attention to disease activity trends is needed to closely monitor the situation, beyond the summer season typically associated with increased activity levels. Likewise, although the situation of herpangina is similar to that of previous years, ongoing monitoring of the activity levels and trends remains important.

For detailed information and the latest situation on HFMD and herpangina, please refer to the following (NIID, IASR, IDWR articles in Japanese):

Department of Infectious Disease Surveillance
National Institute of Infectious Diseases, Japan Institute for Health Security