BDNF and Alzheimer disease: Although the role of SARS-CoV-2 in neurotrophins is an emerging trend, it has been reported that patients positive for SARS-CoV-2 have increased levels of brain-derived neurotrophic factor (BDNF) [90,91], a pivotal regulator of synaptic neuroplasticity, where its dysregulation might mediate in the pathogenesis of diverse neurological diseases such as Alzheimer’s disease (AD) [92].