Like all viruses, SARS-CoV-2, the virus that causes COVID-19, constantly changes through mutation. These mutations add up and create slightly different versions of the virus, called “variants”. Sometimes, a mutation will result in the virus spreading more easily, making people sicker or making it resistant to treatment or vaccines. Variants with these types of mutations are called variants of concern. Scientists continue to study and track these variants as they evolve.
The CDC is tracking a number of variants of concern in the United States. These include:
| Variant name: | First detected: | First found in the US: |
| Alpha (B.1.1.7) | United Kingdom | December 2020 |
| Beta (B.1.351) | South Africa | January 2021 |
| Beta (B.1.351) | In travellers from Brazil | January 2021 |
| Delta (B.1.617.2) | India | March 2021 |
These variants are a serious threat to adults who are not fully vaccinated, especially those who are at higher risk of severe COVID-19 disease. The Delta variant is concerning because it seems to be spreading much more easily than the original virus and other variants. It may also cause more severe infections, including those that lead to hospitalization. The Delta variant is becoming more common in the US, including in Santa Barbara County. Everyone should focus on slowing its spread until we better understand how the Delta variant is spreading and who it is infecting.