What you need to know about the Delta Variant

As the COVID-19 pandemic continues across the world, public health officials are watching certain coronavirus mutations and variants that may be more contagious or deadly than the original strain. Viruses constantly change to adapt and survive, and variants emerge when a strain has one or more mutations that differ from others.

The CDC and World Health Organization (WHO) monitor these variations to find out if transmission could lead to a surge in COVID-19 cases and deaths, as well as whether current vaccines can provide protection. The U.S. classifies them as either a “variant of interest,” which may lead to outbreaks but isn’t widespread in the country; a “variant of concern,” which shows evidence of increased transmission and more severe disease; or a “variant of high consequence,” which makes vaccines and treatments much less likely to work well.

The Delta variant has drawn focused attention during the past month due a rapid increase in COVID-19 cases in several countries, including the U.S.