NEFL and COVID-19: In a COVID-19-related acute necrotising encephalopathy, 19 days after the onset of symptoms and even after testing negative twice for COVID-19, the SARS-CoV-2 was detected in the CSF together with extremely high levels of both the neurofilament light-chain protein (NfL), a biomarker predictive of intra-axonal neuronal injury, and GFAP (Virhammar et al., 2020).