Table 6.

The effectiveness of COVID-19 vaccines to prevent SARS-CoV-2 Omicron variant infection in case–control and cohort studies.

Type of vaccine	No. of studies	Adjust OR/RR (95% CI)	P h/I 2 (%)&	VE (%) (95% CI)#	P	Vaccine name
Case–control studies
To prevent SARS-CoV-2 infection of the Omicron variant (B.1.1.529)
Overall	6	0.673 (0.556, 0.816)	<0.001/98.2	32.7 (18.4, 44.5)	<0.001
RNA-based vaccine	4	0.671 (0.547, 0.823)	<0.001/96.8	32.9 (17.7, 45.3)	<0.001	BNT162b2; mRNA-1273
To prevent symptomatic COVID-19 caused by the Omicron variant (B.1.1.529)
Overall	5	0.352 (0.184, 0.666)	<0.001/99.1	64.8 (33.4, 81.6)	0.001
RNA-based vaccine	4	0.288 (0.212, 0.391)	<0.001/88.5	71.2 (60.9, 79.8)	<0.001	BNT162b2; mRNA-1273
To prevent severe COVID-19 caused by the Omicron variant (B.1.1.529)
Overall	6	0.244 (0.121, 0.492)	<0.001/95.5	75.6 (50.8, 87.9)	<0.001	BNT162b2; mRNA-1273
Cohort studies
To prevent SARS-CoV-2 infection of the Omicron variant (B.1.1.529)
Overall	11	0.622 (0.544, 0.707)	<0.001/97.5	37.8 (29.3, 45.6)	<0.001
RNA-based vaccine	10	0.634 (0.529, 0.761)	<0.001/97.3	36.6 (23.9, 47.1)	<0.001	BNT162b2; mRNA-1273
To prevent severe COVID-19 caused by the Omicron variant (B.1.1.529)
Overall	5	0.467 (0.367, 0.595)	<0.001/85.4	53.3 (40.5, 63.3)	<0.001
RNA-based vaccine	3	0.319 (0.172, 0.593)	0.030/71.5	68.1 (41.7, 82.8)	<0.001	BNT162b2; mRNA-1273
To prevent severe COVID-19 caused by the Omicron variant (BA.2)
Overall	4	0.192 (0.109, 0.338)	<0.001/87.7	80.8 (66.2, 89.1)	<0.001
RNA-based vaccine	2	0.124 (0.084, 0.185)	0.227/31.6	87.6 (81.5, 91.6)	<0.001	BNT162b2
Inactivated virus	2	0.291 (0.154, 0.545)	0.010/0.54	70.9 (45.5, 84.6)	<0.001	CoronaVac
To prevent COVID-19-related death by the Omicron variant (BA.2)
Overall	8	0.099 (0.060, 0.164)	<0.001/88.6	90.1 (83.6, 94.0)	<0.001
RNA-based vaccine	4	0.070 (0.043, 0.113)	0.038/64.5	93.0 (88.7, 95.7)	<0.001	BNT162b2
Inactivated virus	4	0.137 (0.070, 0.270)	<0.001/90.3	86.3 (73.0, 93.0)	<0.001	CoronaVac

^#Vaccine effectiveness = 100*(1–RR/OR) %; ^& NA, not available.