Table 2.

Protective effectiveness of previous SARS-CoV-2 infection

	RR (95% CI)	Protective effectiveness*(95% CI)
Whole cohort: confirmed reinfections	0·06 (0·03–0·12); p<0·001	94·1% (88·2–97·0)
Residents: confirmed reinfections	0·04 (0·02–0·11); p<0·001	95·9% (88·9–98·5)
Staff: confirmed reinfections	0·08 (0·03–0·21); p<0·001	91·8% (78·6–96·8)
Whole cohort: all suspected reinfections	0·15 (0·09–0·24); p<0·001	85·5% (76·1–91·1)

RR=relative risk.

^*Calculation of protective effectiveness of previous natural infection calculated using Poisson regression, 100x (1–RR).