"Although fatigue is measured in different ways, and levels vary per country, it is now estimated to have reached over 60 percent in some cases," WHO Europe Director Dr Hans Kluge said.
He said this is based on "aggregated survey data from countries across the region."
Citizens have made "huge sacrifices" over the last eight months to try and contain the coronavirus, he said in a statement.
"In such circumstances, it is easy and natural to feel apathetic and demotivated, to experience fatigue."
Kluge called on European authorities to listen to the public and work with them in "new and innovative ways" to reinvigorate the fight against Covid-19, which is on the increase throughout Europe.
He cited examples of how certain European countries are working to minimize the likelihood of a "pandemic fatigue" from occurring.
A local authority in the UK has consulted communities to gauge their feelings and a municipality in Denmark involved students in drawing up restrictions that allow them to return to university.