Pinellas County hadn't seen a case of measles in 20 years. Then suddenly last week it had three, all from unvaccinated people.

While some local physicians were not surprised that the highly contagious virus made its way back into Tampa Bay, most are reiterating the safety and importance of routine vaccinations in an era when some parent groups claim immunizations do more harm than good.

Some doctors say they are finding it more difficult to offer medical advice to parents who are passionate about anti-vaccination.

"You want patients to trust you and to trust your advice. That takes time and rapport," said Dr. John Morrison, a family medicine physician with Florida Hospital in Wesley Chapel. "But some people are lulled into a false sense of security, where they'd rather battle measles or mumps instead of autism, even though the autism link is unfounded."

The fallout from the small outbreak has been felt in a variety of ways.

St. Petersburg Pediatrics, a physicians group with nine clinic locations around Tampa Bay, announced that its doctors would no longer treat unvaccinated children. The group posted a sign in their patient waiting rooms last week.

PREVIOUS COVERAGE: Two new cases of measles reported in Pinellas, with the possibility of more

"We have determined that it puts our patients and families at risk and we have decided to minimize that risk," the sign read. "Should you decide not to vaccinate we will continue to see your children for up 30 days to allow you time to find a more suitable pediatrician for your family."

A photo of the sign in the doctor's office was shared widely on Reddit last week. Phone calls to the practice were not returned.

Also last week, SCC Soft Computer, a technology company based in Clearwater, sent out a company-wide email announcing that one of its employees had been diagnosed with measles, Cheryl Kerr, SCC's human resource manager, said in an interview.

"We are working closely with the health department," she said. "We notified everyone who works in this facility. It was just one employee, who hasn't been in the building in days."

The virus was once eradicated in the U.S., thanks to immunizations, but a recent shift in views against routine vaccinations by some parent groups has contributed to its return.

"There is a reason why the government has gone through all this trouble to mass develop vaccinations. They protect people from disease," said Morrison, the Florida Hospital doctor. "It costs more money to treat these diseases than it does to vaccine against them."

The anti-vaccination movement is fueled by parents who believe there is a link between vaccines and autism, though no such link has been proven, or who see more harm than good resulting from having their children vaccinated.

"Honestly, I'm not that surprised. We've seen cases like this nationwide popping up," said Dr. Mark Vaaler, chief medical officer with BayCare, which operates 15 hospitals in Tampa Bay and surrounding areas. "Eventually it would come to us. You just hope it hits us lightly."

As of July, 404 people in Florida were identified as being exposed to measles. The Centers for Disease Control and Prevention reports 107 cases of measles nationwide so far this year. Officials reported 118 cases last year and 86 cases in 2016.

The Florida Department of Health in Pinellas County hasn't reported a new case since Wednesday.

"The majority of cases we see come from people traveling abroad, where measles is still prominent, and they bring it back," said Dr. Beata Casanas, an infectious disease specialist with the University of South Florida.

In interviews, doctors recommended vaccinations and taking precautions like avoiding public places if a child or adult is not vaccinated, and they were united in their message of not to panic.

ALSO READ: Should Florida law require school kids to get the HPV vaccine?

"We used to have measles outbreaks on a yearly basis," Vaaler said. "It is a miserable disease and you don't want it, but it is rare to die from it. A small number can develop severe complications."

Children are the most at risk of developing serious symptoms.

The number of people who choose not to vaccinate appears to be small in Florida. But accurate numbers are hard to come by because reporting to the state's vaccination registry is not mandatory and the registry does not track children in private schools.

Some students with religious exemptions also may have some vaccinations, but not all, health officials said.

That said, the state's vaccination registry shows that 78 percent of 2-year-old children in Pinellas County have received all recommended vaccines. Statewide, the figure is 85 percent.

In Pinellas, 4.1 percent of school-aged children have registered a religious exemption for vaccination. The figure statewide is 2.8 percent.

"We have been working with hospitals and health care providers to make sure they are vigilant for signs of measles," Casanas said. "Not even waiting for the results of the test, we urge them to report even just their suspicions to the health department."

Contact Justine Griffin at jgriffin@tampabay.com or (727) 893-8467. Follow @SunBizGriffin.

__________