AUSTIN (KXAN) — Fully vaccinated with a positive diagnosis of COVID-19: that is the story of 333 people in Travis County since the beginning of the year.

These are the “breakthrough” cases, but it is just a small fraction of the more than 670,000 people in the county who are fully vaccinated.

Jenny Perez tested positive for COVID-19 last month after being fully vaccinated. This is her second bout with the virus. She originally caught COVID-19 in January, so she immediately got tested when she started experiencing familiar symptoms.

“The second time there was a fever and that body-ache and breathing difficulty was by far the worst symptom I had to deal with,” Perez explained.

After getting coronavirus once, she’s been very careful in public, especially to protect her young son, who tested negative. Perez said this time around, she didn’t lose taste or smell, and the virus left sooner.

“The first time it took about a month for me to test negative. The second time, it was within a week,” Perez said.

She was surprised to learn about her diagnosis, just like Regina Pompa, whose fully-vaccinated husband was diagnosed with COVID-19 last week. She said he went to the ER for an unrelated illness and tested positive for COVID-19. He started feeling minor symptoms three days before.

“He was complaining of a sore throat, coughing, headache and runny nose,” Pompa said.

Fortunately, Pompa tested negative for the virus. She said her husband is having a mild case that feels like allergies or a summer cold.

Doctors are seeing less severe symptoms or none at all in breakthrough cases.

“A lot of the cases we are picking up are actually in people with no symptoms, who are getting testing for things like travel or going to a camp or that kind of a scenario,” said Manish Naik, M.D., chief medical officer at Austin Regional Clinic. “And others are having mild or cold-like symptoms. There are occasional cases where people get more sick, even if they’ve been fully vaccinated. But those are unusual and much less common.”

Naik said people with COVID-19-like symptoms should get tested, so they don’t spread the virus to others, especially those who are not vaccinated or to people with a suppressed immune system. We asked the doctor if and why certain people are more susceptible to breakthrough cases than others.

“I think a lot of factors play into whether someone gets a breakthrough infection,” said Naik. “For anyone to have a higher susceptibility for COVID, we know it’s related to your age and your underlying health conditions and how well your immune system is working.”

He said any condition or medication that suppresses your immune system’s function can impact your ability to contract the coronavirus.

Dr. Naik, Pompa and Perez all emphasized the same message Wednesday: get the vaccine and get tested if you have symptoms, vaccinated or not.