Table 4.

Infection rates and adjusted HRs for PCR-confirmed infection after the first dose of vaccine, by vaccine type and days since vaccination (secondary analysis)

	ChAdOx1					BNT162b2
	Person-days at risk	Infection events	Infection rate per 10 000 person-days	Adjusted HR (95% CI)	p value	Person-days at risk	Infection events	Infection rate per 10 000 person-days	Adjusted HR (95% CI)	p value
Unvaccinated	338 003	723	21·39	1 (ref)	..	..	..	..	1 (ref)	..
0–6 days	30 823	61	19·79	0·51 (0·26–0·99)	0·045	16 768	44	26·24	0·84 (0·39–1·81)	0·663
7–13 days	34 598	66	19·08	0·58 (0·35–0·96)	0·035	18 913	73	38·60	1·11 (0·65–1·88)	0·700
14–20 days	32 672	82	25·10	0·95 (0·50–1·84)	0·889	17 690	50	28·26	0·77 (0·37–1·58)	0·473
21–27 days	30 640	50	16·32	0·73 (0·37–1·44)	0·358	16 874	45	26·67	0·94 (0·50–1·79)	0·859
28–34 days	27 041	23	8·51	0·33 (0·16–0·68)	0·0025	16 095	19	11·80	0·47 (0·20–1·06)	0·070
35–48 days	34 705	36	10·37	0·32 (0·15–0·66)	0·0023	28 307	23	8·13	0·35 (0·17–0·71)	0·0038
≥49 days	7421	16	21·56	0·64 (0·26–1·56)	0·329	20 078	24	11·95	0·38 (0·15–0·93)	0·034
Total (vaccine type)	197 900	334	16·88	..	..	134 725	278	20·63	..	..

Adjusted HRs were estimated using Cox proportional hazards regression according to days since the first vaccine dose for each vaccine type (ChAdOx1 and BNT162b2). The comparator was the unvaccinated group. HRs were adjusted for age, sex, local monthly infection incidence, and long-term care facility bed capacity. 95% CIs were calculated using robust standard errors for long-term care facility-level effects. HR=hazard ratio.