COVID-19 cases are rising once again across the United States including hospitalizations, particularly in younger people. Health experts call this the fourth COVID surge.

Experts say the highly contagious B.1.1.7 variant or also known as the "British variant" has caused the uptick in the cases. They added that younger people could be more affected during the latest COVID surge, particularly for those that have not yet been vaccinated.

Dr. Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine, said people have to think of the B.1.1.7 variant as almost as a brand-new virus, according to a KSL report.

"It's acting differently from anything we've seen before, in terms of transmissibility, in terms of affecting young people, so we have to take this very seriously," Hotez was quoted in a report.

Head of the Centers for Disease Control and Prevention, Dr. Rochelle Walensky, confirmed that the U.S. is now entering the fourth week of an increased number of cases.

Walensky added that the trends and the data are pointing to an increase, particularly in younger people.

"Many outbreaks in young people are related to youth sports and extracurricular activities," Walensky was quoted in an NBC News report.

Emergency physician Dr. Leana Wen echoed Walensky's sentiments.

READ MORE: Fauci Says Nation May See a Surge Upon Surge in COVID-19 Cases, No Relaxation in Restrictions

Younger People Infected

Wen said that younger groups are still vulnerable while the B.1.1.7 variant circulates, adding that the variant is more contagious and may cause a more severe symptoms of the disease.

Former Food and Drug Administration Commissioner Dr. Scott Gottlieb said that they are seeing infection in younger people who have not been vaccinated, as well as in school-aged children.

The latest data from NBC News said part of the problem is that Americans have become less afraid of contracting the disease.

Thirty-five percent are worried about getting COVID-19, which 14 percentage points down from February, according to a Gallup survey poll.

COVID Surge

The nation's top infectious disease expert, Dr. Anthony Fauci, said that the vaccine will have a major effect on preventing from having a huge surge, but cannot be overconfident.

Fauci added that this is one of the reasons why they keep saying over and over again to not declare victory against the pandemic prematurely, according to a Yahoo Finance report.

Meanwhile, U.S. President Joe Biden announced on Tuesday that he will be moving his deadline by two weeks earlier for states to make all adults in the U.S. eligible for the vaccine.

Biden backed Fauci's statement by saying that the U.S. is not at the finish line, adding that there is still a lot of work to do.

Some states had already begun moving up their deadlines from the original May 1 date.

Biden advised getting the vaccine if you can, noting that that is the way to beat the pandemic, according to an Associated Press report.

Since his inauguration on Jan. 20, Biden said that 150 million doses of the COVID-19 vaccine have been administered.

His original goal had been to have 100 million shots given by the end of his 100 days in office, but this was achieved in March.

READ NEXT: Fauci Says Normality is Impossible in 2021 Without a COVID-19 Vaccine 

WATCH: Experts say most new COVID-19 cases affecting young people more -from WCNC