Avian influenza is caused by influenza A viruses primarily found in waterfowl. Humans can contract the infection from infected birds or materials contaminated with bird droppings, but human-to-human transmission is rare. The disease can range from asymptomatic or mild respiratory infections to severe symptoms. Old age and underlying diseases increase the risk of serious disease. Vaccination is offered free of charge to individuals aged 18 and older who are at increased risk of avian influenza, such as those working in relevant occupations.

• THL, Infektiotaudit: Lintuinfluenssa (in Finnish)
• THL, Rokotteet: Lintuinfluenssarokote (in Finnish)
• WHO, Fact Sheet, Influenza (Avian and other zoonotic)