McMillan was part of the rink skipped by Fay Henderson due to take part in the world junior-B championships in Lohja, Finland.
The men’s competition got under way on January 3, with the women’ s contest due to follow on Monday of this week.
The men’s event was abandoned after just three days due to concerns over a growing number of positive Covid-19 cases, however, prompting organisers to decided that the women’s competition shouldn’t go ahead either.
World Curling Federation president Kate Caithness said: “It is with deep regret that we have been forced to cancel the world junior-B curling championships 2022.
“I know how disappointing this decision will be for our young athletes, but their safety, together with that of our officials, staff and volunteers, will always be our first concern.”