GI	Gastrointestinal
CDC	Centers of Disease Control and Prevention
WHO	World Health Organization
IAV	Influenza A
IBV	Influenza B
ICV	Influenza C
IDV	Influenza D
SA	Sialic acid
HA	Hemagglutinin
NA	Neuraminidase
RNA	Ribonucleic acid
HEF	Hemagglutinin-esterase-fusion
9-O-Ac	N-acetyl-9-O-acetylneuraminic
Y/o	Years old
RT-PCR	Reverse transcription polymerase chain reaction
CT	Computed tomography
PCR	Polymerase chain reaction
IFN	Interferon
IL	Interleukins
TLR	Toll-like receptor
TGF	Transforming growth factor
TNF	Tissue necrosis factor
CCL	C-C-motif chemokine ligands
CXCL	C-X-C motif chemokine ligands
ILC2	Group 2 innate lymphoid cells
SCFA	Short-chain fatty acids
BCAA	Branched-chain amino acids
RSV	Respiratory syncytial virus
HSPG	Heparan sulfate proteoglycans
CX3CR1	CX3C chemokine receptor 1
IGFR-1	Insulin-like growth factor 1 receptor
EGF	Epidermal growth factor
ICAM-1	Intercellular adhesion molecule 1
SARS-CoV-2	Coronavirus
ACE2	Angiotensin converting enzyme 2
TMPRSS2	Transmembrane serine protease 2