Epidemiological Characterization of Patients in the First Eight Weeks Following Detection of SARS-CoV-2 B.1.1.529 (omicron) Variant in Cuba.

Omicron's rapid expansion in Cuba was associated with increased incidence but not with a higher case fatality rate. The relatively milder disease in those infected with this variant could be influenced by the high vaccination coverage, along with the natural immunity acquired as a consequence of previous virus infection.