Disclaimer: Early release articles are not considered as final versions. Any changes will be reflected in the online version in the month the article is officially released.
Volume 28, Number 1—January 2022
Mask Effectiveness for Preventing Secondary Cases of COVID-19, Johnson County, Iowa, USA
|Variable||Negative||Positive||Secondary attack rate (95% CI), %|
|Exposure duration, h|
|Direct exposure||9||5||35.7 (17.7–72.1)|
|Multiple settings||72||25||25.8 (18.4–36.1)|
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Page updated: October 12, 2021
Page reviewed: October 12, 2021
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