*Gunma Children’s Medical Center Shibukawa
§Gunma Prefectural Institute of Public Health and Environmental Sciences Maebashi, Gunma
†Department of Pediatrics, Okayama University Hospital, Okayama
‡Department of Pediatrics, Shinshu University School of Medicine, Matsumoto Nagano
∥Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa
¶Infectious Disease Surveillance Center National Institute of Infectious Diseases Musashimurayama-shi, Tokyo, Japan
Supported by a grant for Cancer Research, and a grant for Research on Children and Families and on Emerging Infectious Diseases from the Ministry of Health, Labor, and Welfare of Japan, a Grant-in-Aid for Scientific Research (B, C) and Exploratory Research from the Ministry of Education, Culture, Sports, Science, and Technology of Japan and by a Research grant for Gunma Prefectural Hospitals.
K.W., H.S., and Y.H.: designed the research; Y.S., M.P., M.S., R.Y., and K.K.: performed the research; K.W., H.S., A.K., H.K., K.K., H.T., and A.R.: analyzed the data; and K.W., A.S., H.K., and Y.H.: wrote the paper.
The authors declare no conflict of interest.