NEFL and COVID-19: Signs of neuro‐inflammation and neuroaxonal and glial degeneration, measured with neurofilament light chain and glial fibrillary astrocytic protein, were lower in the blood of people with persistent headache in the phase after the resolution of acute COVID‐19 compared to people with severe COVID‐19, indicating no neuroaxonal and glial damage or reactive gliosis in people with long‐term persistent headache after COVID‐19 [78].