Table 3.

Respiratory Protection Utilized Most Frequently During Contact With COVID-19 Patients

				All Cases, Unadjusteda		All Cases, Adjusted		Early Sensitivity Cohortb		Late Sensitivity Cohortc		Contemporaneous Cohortd
During AGPs		During Non-AGPs	Total	OR	P Value	OR	P Value	OR	P Value	OR	P Value	OR	P Value
Respirator	+	Respirator	242	0.4 (0.2–0.8)	.003	0.4 (0.2–0.8)	.005	0.2 (0.06–0.5)	<.001	0.7 (0.3–1.5)	.35	0.5 (0.1–2.4)	.42
Respirator	+	Medical mask	55	1.0 (0.5–2.1)	.99	1.0 (0.4–2.3)	.94	1.1 (0.3–3.9)	.84	0.8 (0.3–2.1)	.68	0.6 (0.06–5.2)	.62
Medical mask	+	Medical mask	18	7.4 (2.8–20.0)	<.001	9.1 (2.8–29.9)	<.001	38.3 (7.7–189.9)	<.001	3.9 (1.0–14.6)	.04	4.7 (0.4–53.2)	.21
(No exposure)	+	Respirator	208	1.1 (0.7–1.6)	.67	1.2 (0.8–1.9)	.43	0.8 (0.4–1.6)	.48	1.3 (0.8–2.0	.36	1.6 (0.7–3.4)	.23
(No exposure)	+	Medical mask	99	1.7 (1.1–2.7)	.02	1.6 (0.9–2.6)	.09	1.9 (0.9–3.9)	.10	1.2 (0.6–2.1)	.65	1.1 (0.5–2.9)	.80

^aMedian exposure windows Apr 14–28, 2020 (controls, n=886) and Mar 20–Apr 3, 2020 (all cases, n = 244).

^bMedian case exposure window Mar 3–17, 2020 (n=101).

^cMedian case exposure window Apr 3–17, 2020 (n=141).

^dMedian case exposure window Apr 10–24, 2020 (n=54).