HOPKINTON, Mass. -- A Boston Marathon tradition that brought Kenyan runners to a MetroWest elementary school was canceled this year after several students developed chicken pox.

Kenyan runners have been visiting second- and third-graders at Elmwood Elementary School in Hopkinton for the past 15 years.

But when 19 Elmwood students developed chicken pox, the event was moved to the high school, and fourth- and fifth-graders from the Hopkins School where scheduled to meet the runners. But then several Hopkins students also developed chicken pox.

Since the disease is not as prevalent in Kenya as it is in the United States, advisers from the marathon's medical team and the state Public Health Department recommended canceling the event.

"It's very disappointing this year because you don't really get to run with them because of the chicken pox," said third-grader Heather Holly.

"It really is quite unusual. We've never had this many cases, and the timing of it is really pretty awful. It's not serious for the children -- it's very minor," said Principal Ilene Silver.

Tom Keane had been getting his third-grade class ready for the visit by teaching them about Kenya.

"To understand the culture and understand a little more about the people of Kenya before the Kenyan runners get here," he said.

"My Kenyan runner was (Robert) Cheruiyot, and he won the Boston Marathon three times -- came in first place. And I really wanted to meet him," said second-grader Rachel Zale.

The program should return to the school next year.

"I think that it is very disappointing news, but we will see them next year because they will include us in the (school) ceremony," said third-grader Nick Temple.