SARS-Cov-2	severe acute respiratory syndrome coronavirus 2
COVID-19	coronavirus disease 2019
VE	vaccine effectiveness
CI	confidence interval
OR	odds ratios
ICU	intensive care unit
GMTs	geometric mean neutralizing titers
SMD	standard mean difference
PRISMA	preferred reporting items for systematic reviews and meta-analyses
WHO	World Health Organization
rt-PCR	reverse-transcription polymerase chain reaction
RCTs	randomized controlled trial
NAAT	nucleic acid amplification test