Regular flu shot clinics are back in operation in Whitehorse, and officials are urging those planning to travel to the Arctic Winter Games in Fairbanks to get immunized.
Clinics had been postponed when supplies of the flu vaccine had run out.
Brendan Hanley, Yukon's chief medical officer of health, says more than 250 people were vaccinated on Friday.
More than 50 people in Yukon have had confirmed cases of flu, and four people have been hospitalized.
"We've had four overall hospitalizations that we know of, with flu," he said. "It doesn't sound very much, but for us that's quite a big number. All of them did have underlying medical conditions."
Hanley says the vast majority of confirmed cases of flu are of the H1N1 strain, which affects younger and middle-aged adults. He says other flu strains are under intense global surveillance, because they can become pandemics.
Hanley is urging athletes, chaperones and family members who are travelling to the Arctic Winter Games in Fairbanks, Alaska, in March to get their flu shots now. The flu vaccine takes two weeks from when you get the shot to become effective.