Because the virus that causes COVID-19 is constantly mutating, the Centers for Disease Control and Prevention (CDC) expects new variants to continue to emerge. The CDC is working with state and local public health officials to monitor the spread of all variants. Some variants will come and go. Others will widely spread and replace earlier variants. Recent variants of COVID-19 include Delta and Omicron.

What Causes a Variant?

A mutation is a single change in a virus’s genetic code. A virus variant contains one or more mutations. Viruses constantly change, and sometimes these mutations create new variants. COVID-19 variants can be more or less contagious than the original strain, and the severity of symptoms varies from strain to strain.

Slowing the Spread and Emergence of New Variants

While breakthrough infections are expected, getting vaccinated and boostered against COVID-19 greatly lowers the risk for severe illness, hospitalization, and death from any known COVID-19 variant. This further emphasizes the importance of vaccination and boosters.

The same guidelines that help prevent the spread of COVID-19 from person to person can help slow the development and spread of its variants.

These guidelines include:

• isolating when ill and contagious with COVID-19
• social distancing
• wearing a mask
• hand sanitation
• staying up to date on the COVID-19 vaccine, including getting booster shots when eligible