SARS-CoV-2, the virus causing COVID-19, constantly evolves through genetic mutations and recombinations, leading to numerous variants that differ from the original strain.

SARS-CoV-2 variants are categorized based on their genetic mutations and the resulting public health implications. These categories include Variants of Interest (VOI), Variants of Concern (VOC), Variants of High Consequence (VOHC), and Variants Being Monitored (VBM). Each classification represents a different level of threat based on factors such as transmissibility, severity of disease, and impact on diagnostic, therapeutic, and preventive measures. The detailed definitions and criteria for these classifications can be found on the CDC's variant classifications page.

• A Variant of Concern (VOC) includes those that show increased transmissibility, more severe disease (e.g., higher hospitalizations or deaths), or significant reduction in neutralization by antibodies from previous infection or vaccination.
• A Variant of High Consequence (VOHC), a more severe classification, is characterized by clear evidence of significantly reduced effectiveness of medical countermeasures.

Currently no SARS-CoV-2 variants are designated as VOC or VOHC. The last VOC was Omicron, which emerged in November 2021 and caused a worldwide wave of cases. At its peak, Omicron exceeded 20,000 daily hospital admissions in the United States for a period of approximately 2 weeks