PRISMA	The Preferred Reporting Items for Systematic Reviews and Meta-Analyses Statement
MeSH	Medical subject headings
WHO	World Health Organization
CDC	Center for Disease Control
RCT	Randomized clinical trial
COVID-19	Coronavirus disease 2019
alum	Potassium aluminum sulfate
VLPs	Virus-like particles
ORs	Odds ratios
6-HB	six-helical bundle
SARS-CoV-2	Severe acute respiratory syndrome coronavirus 2
95% CI	95% confidence interval
GMT	Geometric mean titer
RBD	Receptor-binding domain
PLpro	Papain-like proteases
3CLpro	Cysteine-like protease
NAb	Neutralizing antibody
Pro-subunit	Protein subunit
VLP	Virus-like particle
BMI	Body mass index
CFR	Case fatality ratio
RNA	Ribonucleic acid
messenger RNA	mRNA
S-protein	Spike protein
ACE2	Angiotensin-converting enzyme 2
nsp	Non-structural proteins
IM	Intramuscular