Lifestyle Health Fauci Warns the U.S. Is 'Going in the Wrong Direction' as New COVID Cases Spike by 170% With the highly contagious delta variant now accounting for more than 80% of cases in the U.S., infections have returned to levels not seen since before vaccines were widely available By Julie Mazziotta Julie Mazziotta Twitter Associate Editor, PEOPLE Health People Editorial Guidelines Published on July 26, 2021 04:28 PM Share Tweet Pin Email Dr. Anthony Fauci. Photo: Susan Walsh/AP/Bloomberg via Getty With less than half of the country fully vaccinated and the highly contagious delta variant making up more than 80% of new COVID-19 cases in the U.S., infections are again soaring to their highest levels in months. The rise in cases — an increase of 170% in the last two weeks — has the U.S. "going in the wrong direction," Dr. Anthony Fauci, the nation's top infectious diseases expert, said Sunday on CNN. On Friday, the U.S. reported 82,505 new COVID-19 cases, the most since February, when vaccines were not yet widely available. Fauci said that the issue "is among the unvaccinated." "Since we have 50% of the country not fully vaccinated, that's a problem," he said. "Particularly when you have a variant like delta which has this extraordinary characteristic of being able to spread very efficiently and very easily from person to person, and we know we have many, many, many vulnerable people in this country that are unvaccinated." The majority of new cases are in unvaccinated people, and hospitals across the country have said that 99% of patients hospitalized with COVID-19 are unvaccinated. "It is really a pandemic among the unvaccinated, so this is an issue predominantly among the unvaccinated, which is the reason why we're out there, practically pleading with the unvaccinated people to go out and get vaccinated," Fauci said. In those that are vaccinated, the virus is "in retreat," he added. "If you are vaccinated, the vaccine is highly protective against the delta variant, particularly against severe disease leading to hospitalization, and sometimes ultimately to death," he said. "It's really an outbreak among the unvaccinated." RELATED VIDEO: Nurse Whose Husband Died of COVID Is on a Door-to-Door Vaccine Crusade: 'I Can Help Save Others' The largest outbreaks in the U.S. are in Missouri, Arkansas, Louisiana and Florida, all of which have less than 50% of residents fully vaccinated. Both Louisiana and Arkansas are well below that number, with 36% fully vaccinated. "It's kind of like we have two kinds of America," Fauci said. "We have the very vulnerable unvaccinated part, and we have the really relatively protected vaccinated part. So if you are vaccinated you are really in a very different category than someone who is not vaccinated." As of July 26, just over 49% of Americans are fully vaccinated against COVID-19, and 56.8% have received at least one dose, according to the Centers for Disease Control. Of those who are eligible for the vaccine, people aged 12 and up, 57.4% are fully vaccinated and 66.4% have received at least one dose. As information about the coronavirus pandemic rapidly changes, PEOPLE is committed to providing the most recent data in our coverage. Some of the information in this story may have changed after publication. For the latest on COVID-19, readers are encouraged to use online resources from the CDC, WHO and local public health departments. PEOPLE has partnered with GoFundMe to raise money for the COVID-19 Relief Fund, a GoFundMe.org fundraiser to support everything from frontline responders to families in need, as well as organizations helping communities. For more information or to donate, click here.