Sami S, Horter L, Valencia D, Thomas I, Pomeroy M, Walker B, Smith-Jeffcoat SE, Tate JE, Kirking HL, Kyaw NTT, Burns R, Blaney K, Dorabawila V, Hoen R, Zirnhelt Z, Schardin C, Uehara A, Retchless AC, Brown VR, Gebru Y, Powell C, Bart SM, Vostok J, Lund H, Kaess J, Gumke M, Propper R, Thomas D, Ojo M, Green A, Wieck M, Wilson E, Hollingshead RJ, Nunez SV, Saady DM, Porse CC, Gardner K, Drociuk D, Scott J, Perez T, Collins J, Shaffner J, Pray I, Rust LT, Brady S, Kerins JL, Teran RA, Hughes V, Sepcic V, Low EW, Kemble SK, Berkley A, Cleavinger K, Safi H, Webb LM, Hutton S, Dewart C, Dickerson K, Hawkins E, Zafar J, Krueger A, Bushman D, Ethridge B, Hansen K, Tant J, Reed C, Boutwell C, Hanson J, Gillespie M, Donahue M, Lane P, Serrano R, Hernandez L, Dethloff MA, Lynfield R, Como-Sabetti K, Lutterloh E, Ackelsberg J, and Ricaldi JN
During November 19-21, 2021, an indoor convention (event) in New York City (NYC), was attended by approximately 53,000 persons from 52 U.S. jurisdictions and 30 foreign countries. In-person registration for the event began on November 18, 2021. The venue was equipped with high efficiency particulate air (HEPA) filtration, and attendees were required to wear a mask indoors and have documented receipt of at least 1 dose of a COVID-19 vaccine.* On December 2, 2021, the Minnesota Department of Health reported the first case of community-acquired COVID-19 in the United States caused by the SARS-CoV-2 B.1.1.529 (Omicron) variant in a person who had attended the event (1). CDC collaborated with state and local health departments to assess event-associated COVID-19 cases and potential exposures among U.S.-based attendees using data from COVID-19 surveillance systems and an anonymous online attendee survey. Among 34,541 attendees with available contact information, surveillance data identified test results for 4,560, including 119 (2.6%) persons from 16 jurisdictions with positive SARS-CoV-2 test results. Most (4,041 [95.2%]), survey respondents reported always wearing a mask while indoors at the event. Compared with test-negative respondents, test-positive respondents were more likely to report attending bars, karaoke, or nightclubs, and eating or drinking indoors near others for at least 15 minutes. Among 4,560 attendees who received testing, evidence of widespread transmission during the event was not identified. Genomic sequencing of 20 specimens identified the SARS-CoV-2 B.1.617.2 (Delta) variant (AY.25 and AY.103 sublineages) in 15 (75%) cases, and the Omicron variant (BA.1 sublineage) in five (25%) cases. These findings reinforce the importance of implementing multiple, simultaneous prevention measures, such as ensuring up-to-date vaccination, mask use, physical distancing, and improved ventilation in limiting SARS-CoV-2 transmission, during large, indoor events. † ., Competing Interests: All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. Ruth Lynfield reports unpaid positions as the President of the Council of State and Territorial Epidemiologists and on the National Foundation for Infectious Diseases Executive Board. Ruby Serrano reports honoraria from Ponce Health Sciences University. No other potential conflicts of interest were disclosed.