The Delta (B1617.2) variant, first detected in India and now sweeping the globe, represents 83% of COVID-19 sequenced samples in United States, according to Centers for Disease Control and Prevention (CDC) Director Rochelle Walensky, MD, MPH, who testified today in a Senate committee hearing on the pandemic."This is a dramatic increase, up from 50% for the week of July 3," Walensky said. "In some parts of the country the percentage is even higher, particularly in areas of low vaccination rates." Walensky explained that the pandemic in the United States was not affecting the unvaccinated.The variant is at least 50% more transmissive than the original, wild type virus.