Finland has not seen any major norovirus outbreaks this season, reports the Finnish Institute for Health and Welfare (THL).
Health officials recorded 121 infections between early September and the end of November, comparable to the same period last year.
Official infection figures, however, generally only tell part of the story, as stomach ailments are almost universally dealt with at home.
Norovirus symptoms include diarrhoea, vomiting and stomach pain, with fever and headaches also possible. Noroviruses, which cause severe stomach flu, begin to spread more frequently in December. The epidemic typically peaks in the early months of the year.
Norovirus is particularly insidious because it can be transmitted from one person to another even before the carrier has any symptoms of the illness.
To prevent infection, the public health authority has advised handwashing for 40 seconds with soap and hot water, as alcohol and hand sanitiser do not kill norovirus.
People at higher risk of severe norovirus symptoms include small children, people over 70 and those with compromised immunity.