For example, showing elevation of biomarkers predicted to be raised in this scenario, or by neuroimaging and neuropathological correlates of microvascular pathology.34–36 A neuroinflammatory mechanism, marked by high C-C motif chemokine 11 (CCL11) levels in CSF, may also contribute to post-COVID cognitive deficits via CCL11-mediated microglial activation.37 Regardless of the mechanism(s), it remains to be explained why the increased risk of a new diagnosis of brain fog (Table 1) and dementia15 persists for up to 2 years after COVID-19 infection. Here, CCL11 is linked to Cognitive impairment.