In the case of COVID-19, it is said that the lower the cholesterol, the higher the severity.
A group from Malmö University, Sweden, etc. has reported that the Spike protein removes lipids and cholesterol from model membranes, and upon co-incubation of both the SARS-CoV-2 spike protein and HDL on model membranes, the levels of lipid removal from the membrane was suppressed, from experiments using model membranes and through interactions with SARS-CoV-2 Spike with and without HDL.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8195693/
This suggests that the higher the concentration of cholesterol existing on the membrane and in serum, the lower the adsorption of SARS-CoV-2 spike onto the membrane, in other words, the higher the cholesterol, the lower the infectivity.
Incidentally, the model membrane used here was deuterated 1,2-dimyristoyl-D54-3-sn-glycerophosphatidylcholine (dDMPC) and perdeuterated cholesterol (dcholesterol) at a molar ratio of 80:20 mol%.