SIRT1 and susceptibility to pneumonia measurement: There is evidence that the PPARα/γ-adenosine 5′-monophosphate- (AMP-) activated protein kinase- (AMPK-) sirtuin-1 (SIRT1) pathway and fatty acid metabolism may be involved in influenza A virus (IAV) replication and pneumonia caused by IAV (Bei et al., 2021).