About the Authors

Yoshiaki Gu

ygu@med.tohoku.ac.jp

Affiliations Department of Regional Cooperation for Infectious Diseases, Tohoku University Graduate School of Medicine, Sendai, Japan, Field Epidemiology Training Program-Japan/Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan

Tomoe Shimada

Affiliation Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan

Yoshinori Yasui

Affiliation Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan

Yuki Tada

Affiliation Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan

Mitsuo Kaku

Affiliation Department of Infection Control and Laboratory Diagnostics, Tohoku University Graduate School of Medicine, Sendai, Japan

Nobuhiko Okabe

Affiliations Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan, Kawasaki City Institute for Public Health, Kawasaki, Japan

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: YG TS YY YT. Performed the experiments: YG TS YY YT. Analyzed the data: YG TS YY YT MK NO. Contributed reagents/materials/analysis tools: YG TS YY YT MK NO. Wrote the paper: YG TS.