SARS-CoV-2 B.1.1.529 (Omicron) Variant Transmission Within Households — Four U.S. Jurisdictions, November 2021–February 2022
Julia M. Baker, Jasmine Y. Nakayama, Michelle O’Hegarty, Andrea McGowan, Richard A. Teran, Stephen M. Bart, Katie E. Mosack, Nicole Roberts, Brooke Campos, Alina Paegle, John McGee, Robert A. Herrera, Kayla English, Carla Barrios, Alexandria B. Davis, Christine Roloff, Lynn Sosa, Jessica Brockmeyer, Lindsey Page, Amy E. Bauer, Joshua Weiner, Manjeet Khubbar, Sanjib Bhattacharyya, Hannah L. Kirking, Jacqueline E. Tate
Abstract
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.