Table 4. Effect of unvaccinated vaccination history on incidence and fatality rate.

Variables			1st and 2nd vaccination		3rd vaccination
			Relative risk (95% CI)	Adjusted relative risk (95% CI)	Relative risk (95% CI)	Adjusted relative risk (95% CI)
Attack rate (n=294)
	Total		0.68 (0.44–1.05)	0.63 (0.40–0.99)	0.61 (0.42–0.90)	0.77 (0.51–1.18)
	Type of variants
		Delta	0.75 (0.42–1.31)	0.70 (0.39–1.28)	0.23 (0.13–0.42)	0.42 (0.22–0.81)
		Omicron	0.59 (0.30–1.17)	0.56 (0.28–1.11)	0.87 (0.49–1.55)	1.14 (0.63–2.08)
	Age, years
		<65	0.51 (0.23–1.16)	0.44 (0.18–1.08)	0.51 (0.26–1.00)	0.68 (0.32–1.46)
		≥65	0.76 (0.45–1.27)	0.73 (0.43–1.24)	0.87 (0.54–1.40)	0.87 (0.52–1.45)
	Gender
		Male	0.58 (0.31–1.09)	0.59 (0.31–1.12)	0.56 (0.31–1.01)	0.82 (0.43–1.56)
		Female	0.73 (0.39–1.35)	0.70 (0.37–1.34)	0.76 (0.45–1.29)	0.73 (0.41–1.31)
	Group
		Inpatients	0.73 (0.45–1.17)	0.71 (0.44–1.15)	1.00 (0.63–1.58)	0.98 (0.61–1.57)
		Staff members	0.37 (0.11–1.19)	0.29 (0.08–1.04)	0.56 (0.24–1.31)	0.34 (0.13–0.88)
Fatality rate (n=25)
	Total		0.37 (0.14–1.02)	0.35 (0.13–0.97)	0.19 (0.08–0.50)	0.45 (0.17–1.19)
	Type of variants
		Delta	0.40 (0.12–1.36)	0.38 (0.11–1.30)	0.10 (0.02–0.48)	0.23 (0.04–1.17)
		Omicron	0.31 (0.05–1.93)	0.27 (0.04–1.72)	0.30 (0.08–1.21)	0.70 (0.17–2.89)
	Age, years
		<65	0.16 (0.02–1.54)	0.10 (0.01–1.10)	0.03 (0.00–0.33)	0.11 (0.01–1.11)
		≥65	0.48 (0.15–1.54)	0.48 (0.15–1.53)	0.45 (0.15–1.32)	0.63 (0.21–1.95)
	Gender
		Male	0.43 (0.12–1.54)	0.47 (0.12–1.87)	0.28 (0.08–1.01)	0.34 (0.08–1.43)
		Female	0.26 (0.05–1.45)	0.16 (0.02–1.08)	0.16 (0.04–0.65)	0.52 (0.10–2.82)
	Group
		Inpatients	0.35 (0.13–0.98)	0.35 (0.13–0.97)	0.42 (0.16–1.08)	0.45 (0.17–1.19)
		Staff members	-	-	-	-

Among the dead, there were no workers or anyone who had completed the first vaccination.

CI, confidence interval.