MIAMI (CBSMiami) – The U.S. Food and Drug Administration has given the greenlight on booster shots to be mixed, meaning any combination of vaccines from the leading three manufacturers. This could help many Americans, particularly healthcare workers who are on the frontlines.

“We know that the frontline workers received the vaccines very early on, so the time has passed, and their level of immunity has gone down,” Dr. Aileen Marty, FIU infectious disease specialist said.

READ MORE: Arrest Made After Social Media Threat Targets Marjory Stoneman Douglas High

Dr. Marty helps track COVID data, she told CBS 4, the rate of vaccination among those eligible to get the booster shot is high.

Currently, it’s open to those who are 65 and older, immunocompromised, as well as those who work in high-risk settings, like health workers.

The booster is important to consider – because the more time that passes – the fewer antibodies you have. Healthcare workers were among the earliest to get their shots.

“So once those immune levels go down, you still have enough to protect from that severe disease and hospitalization and death, but you don’t necessarily have enough to keep from being infected and being able to transmit to others,” Marty explained.

That’s why the booster shot makes a lot of sense, especially as the coronavirus is still able to spread to medical workers, some of whom had breakthrough cases.

READ MORE: CBS4 Exclusive: Support Beams At Dadeland Mall Parking Garage Alarms Shoppers

“We have had hospitalizations in healthcare workers even after being vaccinated that does occur what we don’t see are the amount of deaths OR ICU admissions,” Dr. Sergio Segarra, Baptist Health South Florida Chief Medical Officer said.

He credits the vaccine with helping prevent breakthrough cases from becoming worse. Some COVID variants have much higher viral loads, such as the Delta variant.

“Well we are seeing breakthrough cases,” Dr. Magaret Gorensek, Holy Cross Hospital Pediatric Infectious Disease Specialist said.

Dr. Gorensek compared the Delta variant’s contagion factor to that of chickenpox.

“All the cases in our healthcare workers about 50 percent who did test positive had been vaccinated but none of them had to be admitted they were mild symptoms,” Gorensek told CBS 4.

Though breakthrough cases grab attention, there are often underlying conditions that contribute to how well a person can fight a virus.

MORE NEWS: Florida Farmers Grapple With Transportation Problems

All physicians emphasized the need for everyone who remains unvaccinated to get their shots.

Jacqueline Quynh