California has had more than 120,000 new cases of COVID-19 in the last two weeks, and health officials say a surprising majority of them are under age 49. This confirms a trend reported earlier this month by CNBC that the average age of U.S. coronavirus patients is dropping.

According to Fox News, the California Department of Public Health (CDPH) reported that the state's total number of cases is 400,760 and of those, 276,023, or 69%, are people under the age of 49.

Dr. Sonia Y. Angell, director of the CDPH, said that "by staying home and practicing physical distancing, you're helping bend the curve."

About two-thirds of the residents of California are in that age range, but many of them are under 18. This group, however, accounts for only 9% of cases, so the majority — 60% — of new coronavirus cases occurs in those aged 18 to 49.

Experts say that as some states reopened, young people flocked to restaurants and bars, disregarding social distancing and face mask recommendations. Dr. Anthony Fauci, director of the National Institutes of Allergy and Infectious Disease, told CNBC "it's a serious situation that we have to address immediately."

Fauci said that the average age of people getting infected is 15 years younger than it was a few months ago. He issued a warning to young people that "a risk for you is not just isolated for you. You are innocently and inadvertently propagating the process of a pandemic."

Centers for Disease Control and Prevention (CDC) officials also attributed a large portion of increasing case numbers to young people. CDC Director Dr. Robert Redfield said that while younger, asymptomatic individuals are at a lower risk of complications and death from COVID-19, they may "unwittingly" transmit the virus to elders and those with underlying health conditions.