The virus consistently changes through mutation; some mutations make the virus easier to spread or more difficult to treat. Based on the variants’ clinical consequences, CDC classifies the variants into 3 categories:
1. Variants of Interest: variants that potentially have an effect on increased virus spread and reduced treatment efficacy. Currently on the list: B.1.526 (New York); B.1.525 (New York); P.2 (Brazil)
2. Variants of Concern: There is evidence of an increased transmission, more severe disease, and decreased response to antibody neutralization (decreased efficacy of vaccines). Currently on the list: B.1.1.7 (UK); P.1 (Japan/Brazil); B.1.351 (South Africa); B.1.427 (California); B.1.429 (California).
3. Variant of High Consequence: clear evidence that prevention measures or medical countermeasure have significantly reduced effectiveness relative to the previously circulating variants. Currently on the list: None