ST. PETERSBURG, Fla. — Right now, Florida is under a health advisory because of the increase of Hepatitis A.

On Wednesday, two counties in south Florida reported new cases, and the county with the most amounts of cases is Pinellas.

Two years ago there were no cases of Hep A in Pinellas. In February of this year, there were 52.

By then, 231 cases were reported statewide.

Pinellas had almost one in four cases of Hep A.

There's no patient zero, but there are reasons why it's spreading.

"We definitely are seeing sustained increases," said Kevin Baker, Epidemiology Program Manager at the Pinellas Health Department. "So it's definitely alarming."

Pinellas health officials said having the vaccine is the key.

A state report published last week found 97 percent of people infected with the virus since the beginning of last year did not have the vaccination.

It's why the population most affected is 30 to 39-year-olds.

"It wasn't even developed until the mid-90s,” explained Baker. "So a lot of people my age and older are usually not vaccinated."

Baker said there's also a misconception about Hep A. It's not sexually transmitted.

Hep A can be transferred just as easily by someone infected not washing their hands.

"They can contaminate those surfaces and all someone has to do is get that virus from the food or on a surface into their mouth and they could get infected," said Baker.

Officials said the solution to stop the spreading is to get the vaccine.

The Pinellas Health Department is offering the vaccine for free.

Pasco County is also one of the counties with a high rate of Hep A. The state report shows counties along the Interstate 4 corridor are also seeing higher numbers of the virus.​