Table 2. Open in new tab Effectiveness...

		Test-negative controls	Test-positive cases	Time since last dose in days	VE % (95% CI)^a
≤2 months	Vaccinated	8 (62%)	5 (38%)	42 (39, 48)	86.2%	93.2%
Unvaccinated	262 (22%)	923 (78%)		(77.8; 91.4)	(67.2; 98.6)
>2 and ≤4 months	Vaccinated	23 (66%)	12 (34%)	93 (78, 103)	78.4%	82.7%
Unvaccinated	262 (22%)	923 (78%)		(57.0; 89.2)	(55.2; 93.3)
>4 and ≤6 months	Vaccinated	20 (30%)	46 (70%)	146 (132, 159)	54.1%	57.1%
Unvaccinated	262 (22%)	923 (78%)		(−1.9; 79.3)	(10.1; 79.6)
>6 and ≤8 months	Vaccinated	4 (27%)	11 (73%)	189 (174, 204)	36.2%	35.0%
Unvaccinated	262 (22%)	923 (78%)		(−138.6; 82.9)	(−138.3; 82.3)
>8 and ≤10 months	Vaccinated	3 (50%)	3 (50%)	260 (257, 264)	21.2%	28.8%
Unvaccinated	262 (22%)	923 (78%)		(−987.9; 94.3)	(−301.8; 87.4)
>10 and ≤12 months	Vaccinated	4 (100%)	0 (0%)	307 (298, 323)	NE^b	NE^b
Unvaccinated	262 (22%)	923 (78%)
>12 months	Vaccinated	8 (89%)	1 (11%)	485 (447, 549)	45.6%	36.5%
Unvaccinated	262 (22%)	923 (78%)		(−268.6; 92.0)	(−476.6; 93.0)
All	Vaccinated	70 (47%)	78 (53%)	142 (102, 166)	65.3%	69.2%
Unvaccinated	262 (22%)	923 (78%)		(52.9; 74.5)	(50.1; 80.9)

Test-negative controls

Test-positive cases

Time since last dose in days

VE % (95% CI)^a

Time since last dose

Exposure

N (%)

Median (lower, upper quartile)

GEE

GAM

≤2 months

Vaccinated

8 (62%)

5 (38%)

42 (39, 48)

86.2%

93.2%

Unvaccinated

262 (22%)

923 (78%)

(77.8; 91.4)

(67.2; 98.6)

>2 and ≤4 months

Vaccinated

23 (66%)

12 (34%)

93 (78, 103)

78.4%

82.7%

Unvaccinated

262 (22%)

923 (78%)

(57.0; 89.2)

(55.2; 93.3)

>4 and ≤6 months

Vaccinated

20 (30%)

46 (70%)

146 (132, 159)

54.1%

57.1%

Unvaccinated

262 (22%)

923 (78%)

(−1.9; 79.3)

(10.1; 79.6)

>6 and ≤8 months

Vaccinated

4 (27%)

11 (73%)

189 (174, 204)

36.2%

35.0%

Unvaccinated

262 (22%)

923 (78%)

(−138.6; 82.9)

(−138.3; 82.3)

>8 and ≤10 months

Vaccinated

3 (50%)

260 (257, 264)

21.2%

28.8%

Unvaccinated

262 (22%)

923 (78%)

(−987.9; 94.3)

(−301.8; 87.4)

>10 and ≤12 months

Vaccinated

4 (100%)

0 (0%)

307 (298, 323)

NE^b

Unvaccinated

262 (22%)

923 (78%)

>12 months

Vaccinated

8 (89%)

1 (11%)

485 (447, 549)

45.6%

36.5%

Unvaccinated

262 (22%)

923 (78%)

(−268.6; 92.0)

(−476.6; 93.0)

All

Vaccinated

70 (47%)

78 (53%)

142 (102, 166)

65.3%

69.2%

Unvaccinated

262 (22%)

923 (78%)

(52.9; 74.5)

(50.1; 80.9)

		Test-negative controls	Test-positive cases	Time since last dose in days	VE % (95% CI)^a
≤2 months	Vaccinated	8 (62%)	5 (38%)	42 (39, 48)	86.2%	93.2%
Unvaccinated	262 (22%)	923 (78%)		(77.8; 91.4)	(67.2; 98.6)
>2 and ≤4 months	Vaccinated	23 (66%)	12 (34%)	93 (78, 103)	78.4%	82.7%
Unvaccinated	262 (22%)	923 (78%)		(57.0; 89.2)	(55.2; 93.3)
>4 and ≤6 months	Vaccinated	20 (30%)	46 (70%)	146 (132, 159)	54.1%	57.1%
Unvaccinated	262 (22%)	923 (78%)		(−1.9; 79.3)	(10.1; 79.6)
>6 and ≤8 months	Vaccinated	4 (27%)	11 (73%)	189 (174, 204)	36.2%	35.0%
Unvaccinated	262 (22%)	923 (78%)		(−138.6; 82.9)	(−138.3; 82.3)
>8 and ≤10 months	Vaccinated	3 (50%)	3 (50%)	260 (257, 264)	21.2%	28.8%
Unvaccinated	262 (22%)	923 (78%)		(−987.9; 94.3)	(−301.8; 87.4)
>10 and ≤12 months	Vaccinated	4 (100%)	0 (0%)	307 (298, 323)	NE^b	NE^b
Unvaccinated	262 (22%)	923 (78%)
>12 months	Vaccinated	8 (89%)	1 (11%)	485 (447, 549)	45.6%	36.5%
Unvaccinated	262 (22%)	923 (78%)		(−268.6; 92.0)	(−476.6; 93.0)
All	Vaccinated	70 (47%)	78 (53%)	142 (102, 166)	65.3%	69.2%
Unvaccinated	262 (22%)	923 (78%)		(52.9; 74.5)	(50.1; 80.9)

Table 2.

Open in new tab

Effectiveness of a two-dose primary series of AZD1222, by time since last dose and overall, estimated using GEE and GAM methods in the AstraZeneca COVIDRIVE study

Time since last dose	Exposure	Test-negative controls	Test-positive cases	Time since last dose in days	VE % (95% CI)^a
		Test-negative controls	Test-positive cases	Time since last dose in days	VE % (95% CI)^a
Time since last dose	Exposure	N (%)	N (%)	Median (lower, upper quartile)	GEE	GAM
≤2 months	Vaccinated	8 (62%)	5 (38%)	42 (39, 48)	86.2%	93.2%
≤2 months	Unvaccinated	262 (22%)	923 (78%)		(77.8; 91.4)	(67.2; 98.6)
>2 and ≤4 months	Vaccinated	23 (66%)	12 (34%)	93 (78, 103)	78.4%	82.7%
>2 and ≤4 months	Unvaccinated	262 (22%)	923 (78%)		(57.0; 89.2)	(55.2; 93.3)
>4 and ≤6 months	Vaccinated	20 (30%)	46 (70%)	146 (132, 159)	54.1%	57.1%
>4 and ≤6 months	Unvaccinated	262 (22%)	923 (78%)		(−1.9; 79.3)	(10.1; 79.6)
>6 and ≤8 months	Vaccinated	4 (27%)	11 (73%)	189 (174, 204)	36.2%	35.0%
>6 and ≤8 months	Unvaccinated	262 (22%)	923 (78%)		(−138.6; 82.9)	(−138.3; 82.3)
>8 and ≤10 months	Vaccinated	3 (50%)	3 (50%)	260 (257, 264)	21.2%	28.8%
>8 and ≤10 months	Unvaccinated	262 (22%)	923 (78%)		(−987.9; 94.3)	(−301.8; 87.4)
>10 and ≤12 months	Vaccinated	4 (100%)	0 (0%)	307 (298, 323)	NE^b	NE^b
>10 and ≤12 months	Unvaccinated	262 (22%)	923 (78%)		NE^b	NE^b
>12 months	Vaccinated	8 (89%)	1 (11%)	485 (447, 549)	45.6%	36.5%
>12 months	Unvaccinated	262 (22%)	923 (78%)		(−268.6; 92.0)	(−476.6; 93.0)
All	Vaccinated	70 (47%)	78 (53%)	142 (102, 166)	65.3%	69.2%
All	Unvaccinated	262 (22%)	923 (78%)		(52.9; 74.5)	(50.1; 80.9)

Time since last dose	Exposure	Test-negative controls	Test-positive cases	Time since last dose in days	VE % (95% CI)^a
		Test-negative controls	Test-positive cases	Time since last dose in days	VE % (95% CI)^a
Time since last dose	Exposure	N (%)	N (%)	Median (lower, upper quartile)	GEE	GAM
≤2 months	Vaccinated	8 (62%)	5 (38%)	42 (39, 48)	86.2%	93.2%
≤2 months	Unvaccinated	262 (22%)	923 (78%)		(77.8; 91.4)	(67.2; 98.6)
>2 and ≤4 months	Vaccinated	23 (66%)	12 (34%)	93 (78, 103)	78.4%	82.7%
>2 and ≤4 months	Unvaccinated	262 (22%)	923 (78%)		(57.0; 89.2)	(55.2; 93.3)
>4 and ≤6 months	Vaccinated	20 (30%)	46 (70%)	146 (132, 159)	54.1%	57.1%
>4 and ≤6 months	Unvaccinated	262 (22%)	923 (78%)		(−1.9; 79.3)	(10.1; 79.6)
>6 and ≤8 months	Vaccinated	4 (27%)	11 (73%)	189 (174, 204)	36.2%	35.0%
>6 and ≤8 months	Unvaccinated	262 (22%)	923 (78%)		(−138.6; 82.9)	(−138.3; 82.3)
>8 and ≤10 months	Vaccinated	3 (50%)	3 (50%)	260 (257, 264)	21.2%	28.8%
>8 and ≤10 months	Unvaccinated	262 (22%)	923 (78%)		(−987.9; 94.3)	(−301.8; 87.4)
>10 and ≤12 months	Vaccinated	4 (100%)	0 (0%)	307 (298, 323)	NE^b	NE^b
>10 and ≤12 months	Unvaccinated	262 (22%)	923 (78%)		NE^b	NE^b
>12 months	Vaccinated	8 (89%)	1 (11%)	485 (447, 549)	45.6%	36.5%
>12 months	Unvaccinated	262 (22%)	923 (78%)		(−268.6; 92.0)	(−476.6; 93.0)
All	Vaccinated	70 (47%)	78 (53%)	142 (102, 166)	65.3%	69.2%
All	Unvaccinated	262 (22%)	923 (78%)		(52.9; 74.5)	(50.1; 80.9)

CI, confidence interval; GAM, generalized additive model; GEE, generalized estimating equation; VE, vaccine effectiveness.

Adjusted for onset date, number of chronic conditions, sex, and age.

Non-estimable VE due to zero breakthrough cases, with all test-positive cases occurring in unvaccinated individuals.

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