The Delta variant, a highly contagious COVID-19 variant first identified in India and also known as B1617.2, now accounts for about 6% of US infections, Anthony Fauci, MD, the chief medical adviser to the White House, said yesterday.The variant has become the dominant strain not only in India but also the United Kingdom, where younger people are getting sick more frequently.Fauci said the transmissibility of the Delta variant should prompt any eligible American who has not done so yet to get vaccinated as quickly as possible, as preliminary data show the Pfizer vaccines is 88% effective against the Delta strain.But despite a nationwide push to vaccinate 70% of American adults with at least one dose of vaccine before the Fourth of July,