By CBSMiami.com Team

MIAMI (CBSMiami) – With the U.S. now averaging more than 150,000 new COVID-19 cases a day, we’re hearing about more and more breakthrough cases.

Democratic Sens. Elizabeth Warren of Massachusetts and Cory Booker of New Jersey both tested positive for COVID-19 the weekend of December 18 despite receiving two doses of the vaccine and the booster. Both said their symptoms have been mild so far.

READ MORE: Giant Asteroid To Safely Zoom By Earth On Tuesday

With the highly transmissible Omicron variant spreading, health experts expect more breakthrough cases in the coming weeks.

U.S. Surgeon General Dr. Vivek Murthy says, “No vaccine is perfect, and especially against a foe like Omicron. But those infections are much more likely to be mild compared to maybe somebody who is not boosted or not vaccinated, who may have a greater chance of ending up in the hospital.”

Health experts are also seeing many breakthrough cases among un-boosted people. That includes CBS Moneywatch reporter Diane King Hall.

“It felt like there were knives in my throat,” says King Hall. She continued, “I still think I shouldn’t have been surprised, but I was surprised because I was like, ‘oh my God, I’m vaccinated.'”

READ MORE: On This MLK Day, Some Mobilize To Protect Voting Rights

“More and more of us are thinking of the vaccination series as a three-dose series,” says Dr. William Schaffner of Vanderbilt University Medical Center.

He says vaccinated people who get infected don’t need to wait too long to get their third dose.

“You can get your booster any time after you have recovered, your symptoms have abated,” says Dr. Schaffner.

Health experts say vaccinated people who get infected still need to isolate to prevent the virus from spreading.

MORE NEWS: Broward Law Enforcement Out In Full Force To Prevent ‘Wheels Up, Guns Down’ Chaos

Dr. Schaffner adds people with underlying conditions, such as heart disease and diabetes, should be especially careful right now, regardless of vaccination status, and try to avoid crowds as much as possible.

CBSMiami.com Team