. 2021 Nov 5;11(11):e051491. doi: 10.1136/bmjopen-2021-051491

Table 3.

Secondary attack rate among household and non-household contacts of individuals with COVID-19 by type of exposure and symptom status of primary cases, Tamil Nadu, March–May 2020 (N=14 002)

Type of exposure or symptom status of the primary case	The secondary attack rate (%) (95% CI) (# cases/# contacts of the case)
Type of exposure or symptom status of the primary case	Household	Community contacts	Overall
N=14 002
Congregation	21 (19.0 to 22.9) (352/1686)	1 (0.6 to 1.5) (25/2198)	10 (8.8 to 10.7) (377/3884)
No congregation	6 (5.2 to 7.5) (112/1788)	1 (1.0 to 1.6) (110/8330)	2 (1.9 to 2.5) (222/10118)
N=13 338
Symptomatic	25 (17.6 to 34.1) (26/104)	2 (1.2 to 3.9) (11/503)	6 (4.5 to 8.3) (37/607)
Asymptomatic	12 (10.5 to 12.9) (341/2930)	1 (1.0 to 1.5) (123/9801)	4 (3.3 to 4) (464/12 731)