eLife assessment
Scientists had previously discovered that humans and neanderthals mated leading to parts of neanderthal DNA becoming part of the human genome today. More recently, it was found that a genetic region, carrying which has been associated with manifestation of severe COVID-19 symptoms, is one that was "introgressed" into humans from neanderthals. This region contains many genetic variants, and this study set out to identify which of these genetic variants may be causally involved in creating severe symptoms in response to COVID-19 infection. The main critiques of the study stem from details of the functional assays to establish the regulatory role of the 4 variants in creating severe COVID-19 symptoms. In particular, the two genes (critical chemokine receptor genes: CCR1 and CCR5) that the authors identify as down-regulated by these variants are actually up-regulated in severe COVID-19 patients, leading to doubt about the role of these variants in changing response to COVID-19 through the regulation of these genes. In that regard, it seems necessary to conduct follow-up experimental and computational analyses to establish the role of these variants in altering CCR1 and CCR5 gene expression.