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SARS-CoV-2 B.1.1.529 (Omicron) Variant Transmission Within Households - Four U.S. Jurisdictions, November 2021-February 2022. MMWR Morb Mortal Wkly Rep 2022 Mar 04;71(9):341-346



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Scopus ID

2-s2.0-85125612587 (requires institutional sign-in at Scopus site)   33 Citations


The B.1.1.529 (Omicron) variant, first detected in November 2021, was responsible for a surge in U.S. infections with SARS-CoV-2, the virus that causes COVID-19, during December 2021-January 2022 (1). To investigate the effectiveness of prevention strategies in household settings, CDC partnered with four U.S. jurisdictions to describe Omicron household transmission during November 2021-February 2022. Persons with sequence-confirmed Omicron infection and their household contacts were interviewed. Omicron transmission occurred in 124 (67.8%) of 183 households. Among 431 household contacts, 227 were classified as having a case of COVID-19 (attack rate [AR] = 52.7%). The ARs among household contacts of index patients who had received a COVID-19 booster dose, of fully vaccinated index patients who completed their COVID-19 primary series within the previous 5 months, and of unvaccinated index patients were 42.7% (47 of 110), 43.6% (17 of 39), and 63.9% (69 of 108), respectively. The AR was lower among household contacts of index patients who isolated (41.2%, 99 of 240) compared with those of index patients who did not isolate (67.5%, 112 of 166) (p-value <0.01). Similarly, the AR was lower among household contacts of index patients who ever wore a mask at home during their potentially infectious period (39.5%, 88 of 223) compared with those of index patients who never wore a mask at home (68.9%, 124 of 180) (p-value <0.01). Multicomponent COVID-19 prevention strategies, including up-to-date vaccination, isolation of infected persons, and mask use at home, are critical to reducing Omicron transmission in household settings.

Author List

Baker JM, Nakayama JY, O'Hegarty M, McGowan A, Teran RA, Bart SM, Mosack K, Roberts N, Campos B, Paegle A, McGee J, Herrera R, English K, Barrios C, Davis A, Roloff C, Sosa LE, Brockmeyer J, Page L, Bauer A, Weiner JJ, Khubbar M, Bhattacharyya S, Kirking HL, Tate JE


Katie Mosack PhD Associate Professor in the Psychology department at University of Wisconsin - Milwaukee

MESH terms used to index this publication - Major topics in bold

Child, Preschool
Contact Tracing
Family Characteristics
Middle Aged
United States