The Delta variant of the virus that causes COVID-19 is surging in the United States. New data show Delta is different than past versions of the virus; it is much more contagious. While rare, some vaccinated people can get Delta in a breakthrough infection and may be contagious. Unvaccinated people: get vaccinated and wear a mask until you do. Everyone in areas of substantial or high transmission should wear a mask, even if they are vaccinated. http://www.cdc.gov/coronavirus | CDC