Centers for Disease Control and Prevention.CDC data shows the primary delta variant, known as the lineage B1.617.2, makes up 83.4% of COVID-19 cases.
But when combined with its sublineages, that number grows to 93.4%.The AY.3 sublineage equals 9.1% of cases, the AY.2 makes up 0.8% and the AY.1 accounts for the remaining 0.1%.A sign that reads "Free COVID-19 Testing" at the state-run free COVID-19 testing site set up on Front Street in Reading, PA outside FirstEnergy Stadium Tuesday morning Oct.
13, 2020. (Photo by Ben Hasty/MediaNews Group/Reading Eagle via Getty Images) The CDC calculated the numbers through its national genomic surveillance program, which is tasked with identifying new and emerging COVID-19 variants.