A top medical expert at the Mayo Clinic has a warning for people who have not yet been vaccinated against COVID-19 as positive cases of the virus spike across the country.

According to the Centers of Disease Control and Prevention, 83% of all new cases of the virus are now comprised of the Delta variant – a highly contagious strain of COVID that is increasing the number of deaths and hospitalizations that are occurring in the U.S.

Dr. Gregory Poland, the nation’s leading expert on vaccines, told WCCO, a CBS affiliate out of Minneapolis, “We are seeing the Delta variant really take over.”

The CDC named the Delta mutation a “variant of concern” in June. The COVID strain, which originated in India, has been identified in all 50 states and is now the dominant strain of the virus in the U.S.

Poland, who continues to wear a mask, told WCCO that he was a strict warning for people who have waited to get the COVID vaccine.

“Don’t be deceived that ‘I got this far and I am OK.’ This is a very different variant. It will find you,” he said. “This virus will find everybody who is not immune.”

Poland expressed his concern for young children who are unable to get the vaccine at this time. The Pfizer vaccine has only been authorized for use in children as young as 12-years-old, while Moderna and Johnson & Johnson vaccine can only be administered to people 18 and older.

“We are seeing a rise in severe disease and hospitalizations among young people,” Poland told the news outlet.

He continued by saying that he agrees with the stance of the American Academy of Pediatrics that all children should wear a mask in school this fall no matter if they have been vaccinated or not.

“A mask is not a political symbol. It is a medical symbol of taking care of yourself and others,” he told WCCO.

But Poland maintained that being unvaccinated presents a risk, saying, “This is a serious, current and present danger to you and your families’ health if you are not vaccinated.”

As of Thursday, the CDC reported that over 161.8 million people have been fully vaccinated against COVID-19, accounting for 48.8% of the U.S. population.

The U.S. has reported over 34.2 million positive coronavirus cases and over 609,000 COVID-19 deaths, according to data from Johns Hopkins University.

covid vaccine A COVID-19 vaccine is pictured. Photo: AFP / Nicolas ASFOURI