Health experts have for weeks warned that the continent may be on the cusp of a resurgence of coronavirus cases as mask-weary Europeans mingled barefaced in reopened restaurants and at parties and took up old habits such as greeting each other with a kiss on the cheek.

Developing and maintaining a cohesive health protocol is hard, however, as public attention shifts to jump-starting moribund economies, and mask fatigue sets in. Public appearances by maskless political leaders in the U.K. and France have also drawn criticism from health experts.

Dr. Isabella Annesi-Maesano, an epidemiologist at the French Institute for Health and Medical Research (INSERM), said a collective sense of weariness was leading people to let their guard down. “People have suffered and it shows,” she said…

On Thursday, France’s health minister, Olivier Véran, imparted a new sense of urgency, calling on the French to start observing the new health protocol immediately, saying that there were signs of resurgence of the virus.