ARDS	adult respiratory distress syndrome
ACE2	angiotensin-converting enzyme 2
DNAmAge	biological age based on DNA methylation
CVDs	cardiovascular diseases
COVID-19	coronavirus disease 19
CpGs	cytosine–guanine dinucleotides
DPP-4	dipeptidyl-peptidase IV
MERS	Middle East respiratory syndrome
MERS-CoV	MERS coronavirus
PPCS	persistent post-COVID-19 syndrome
RAS	renin–angiotensin system
SARS	severe acute respiratory syndrome
SARS-CoV-2	severe acute respiratory syndrome coronavirus 2
TL	telomere length
T2DM	type 2 diabetes mellitus