The delta variant accounts for at least 93 percent of all sequenced coronavirus in the U.S., according to estimates from the Centers for Disease Control and Prevention (CDC).
For the two-week period ending July 31, all the different lineages of the delta variant made up about 93 percent of cases that were sequenced.
In some parts of the country with low vaccination rates, especially the Midwest, the percentages are even higher.
Vaccination rates have been uneven across states, and only about half of all eligible people nationwide are fully vaccinated.
Two weeks ago, CDC Director Rochelle WalenskyRochelle WalenskyFDA panel endorses COVID-19 booster shots for older Americans, rejects widespread use Watch live: White House COVID-19 response team holds briefing The Hill's Morning Report - Presented by National Industries for the Blind - Tight security for Capitol rally; Biden agenda slows MORE said the delta variant was responsible for 83 percent of all sequenced COVID-19 cases.
Health officials have described the latest stage of the coronavirus as a "pandemic of the unvaccinated" while emphasizing that those who have had their shots are relatively safe.
The Biden administration has called on Americans to get vaccinated for months before taking a more aggressive approach last week. President BidenJoe BidenHouse clears bill to provide veterans with cost-of-living adjustment On The Money — Dems dare GOP to vote for shutdown, default To reduce poverty, stop burdening the poor: What Joe Manchin gets wrong about the child tax credit MORE announced that federal workers will have to either show proof of vaccination or get regular COVID-19 testing.
Still, the rapid spread of the delta variant has led some major cities to reimpose mask mandates on everyone regardless of vaccination status, as a way to try to blunt the spread of the variant.
Instead of a mask mandate, New York City will require proof of vaccination for workers and customers who want to participate in indoor activities including dining in restaurants, working out in gyms and attending theater performances.