On November 24, 2021, the World Health Organization received notification of a new variant of SARS-CoV-2, B.1.1.529 (WHO). This new variant was discovered in specimens collected in Botswana on November 11, 2021, and in South Africa on November 14, 2021.
On November 26, 2021, WHO designated the B.1.1.529 Omicron as a Variant of Concern (VOC). The United States designated Omicron as a Variant of Concern on November 30, 2021, and the first confirmed U.S. case of Omicron was identified on December 1, 2021.
As we continue to monitor Omicron's trajectory, the CDC has been collaborating with global public health and industry partners to learn more about it. Throughout the pandemic, the CDC has used genomic surveillance to track variants of SARS-CoV-2, the virus that causes COVID-19, and to inform public health practice. We don't know how quickly it spreads or how serious the illnesses it causes.
Regardless of vaccination status, the CDC continues to recommend wearing a mask in public indoor settings in areas with significant or high community transmission. For people who want to learn more about what type of mask is best for them based on their circumstances, the CDC offers mask advice!
