Teresa Dominguez, 55, was doing her weekly shopping near her home in Collado Villalba, north of Madrid, when she realised she was wandering aimlessly, feeling lost in the aisles and without a clue of what she needed.

She paid for what she had already picked out and left.

The "mental mist", as she describes her inability to concentrate, and permanent fatigue after performing the simplest of everyday tasks have constrained her life for the past year, since her March 2020 coronavirus infection developed into what doctors call a post-Covid syndrome, or "long Covid"...