Racing in the Tokyo Marathon on Sunday was canceled amid concerns about a deadly respiratory virus linked to heart failure, authorities announced on Monday.

“The decision to cancel the marathon was made, primarily, out of a concern for public health,” said Hirotaka Sakamoto, the police commissioner for the Tokyo Metropolitan Police. “But we also came to the conclusion it would not be appropriate to subject thousands of runners to running through a city crowded with hundreds of thousands of spectators.”

The decision was announced two days after dozens of runners collapsed and had to be hospitalized. The outbreak started in the area surrounding the JR Kinokawa Station during Sunday’s main race of 62,000 runners and 128,000 spectators.

In all, more than 1,200 people were sickened, according to the Korea Centers for Disease Control and Prevention.

Korean authorities have deployed 230 emergency workers, in addition to 200 doctors, paramedics and support staff, to help investigate and control the outbreak.

In other races, UC Irvine and Santa Monica are scheduled to host road races on Feb. 23.

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