For Michael Miranda of Kauai, sneezing, congestion and other symptoms that began after a trip to the West Coast over the summer hinted at the possibility he was infected with COVID-19.

For Katharina Heyer of Oahu, it was the realization that she could not smell the garlic in the refrigerator during a family trip to Utah in June.

Lisa Crosby-Torres and her husband, Pat Torres, of Kailua believe they contracted the coronavirus from another patient at a hospital after a fall from the stairs landed him in a shared hospital room in late August.

They all tested positive for COVID-19 despite being fully vaccinated with two doses of either the Pfizer or Moderna COVID-19 vaccines, and would be considered breakthrough cases — defined by the Centers for Disease Control and Prevention as the detection of the coronavirus in a person more than 14 days after completing vaccinations.

State Department of Health officials have repeatedly said breakthrough cases are rare and that vaccines still protect people from severe illness, hospitalization and death due to COVID-19.

But breakthrough cases can, and do, happen. Both in Hawaii and nationally, cases seem to have increased since the highly contagious delta variant surged over the summer.

As of Aug. 26, DOH said, about 2,400 breakthrough cases had been identified in the state, representing about 0.3% of the fully vaccinated population. Of those cases, 68 were hospitalized, and eight died from COVID-19-related complications. No updated statistics were available as of Friday.

“Keep in mind the dynamics of the virus are changing, and recent carefully designed research studies indicate COVID-19 vaccines may not provide as high a level of protection against infection as they did when the initial vaccine trials were performed,” said state epidemiologist Dr. Sarah Kemble in a statement at the time. “The declines in vaccine effectiveness that have been demonstrated have to do with the takeover of delta variant, and also might indicate waning of vaccine efficacy over time.”

On Friday thousands of fully vaccinated Hawaii residents became eligible for booster shoots, but DOH recommended priority be given to those ages 65 and older, or those ages 50 to 64 with underlying medical conditions.

The CDC tracks only breakthrough cases that result in hospitalizations and death, but has developed a national breakthrough database for voluntary reporting by state health departments to better understand how the COVID-19 vaccines are working.

Only a handful of states, including California, Louisiana and Oregon, are publicly reporting information on vaccine breakthrough cases. Hawaii is not among them.

Miranda, 41, started feeling symptoms in early July after a trip to the West Coast that involved stops in Seattle, San Francisco, Las Vegas, Utah and San Diego.

After returning to Hawaii, he began to experience a fever, followed by chills. At first he thought it was a cold or sinusitis, which he often gets after traveling on planes.

After having been fully vaccinated with Moderna, he figured the chances were slim that he would catch COVID-19. Then he ordered pizza and realized he could not taste the marinara or cheese.

He called his doctor, got tested and woke up to a notification the next morning that he had tested positive.

At first Miranda, a probation officer, was in disbelief.

“I started blaming everyone that wasn’t wearing mask in Las Vegas,” he said, “then I started wondering if my conditions were going to get worse and if I was going to die.”

Eventually, he realized his symptoms were improving. But it was nerve-wracking worrying about whether he had infected any close contacts. He was part of a large family group that went on the trip. Five others tested positive, he said, but he was the only one with symptoms.

His sense of smell returned after eight days. He always did, and still does, wear a mask.

“I would say get vaccinated and stay vigilant because you never know if you will spread it to someone who is more vulnerable or could be affected in a worse way than I experienced it,” Miranda said.

For Heyer, an associate professor of political science at the University of Hawaii at Manoa, the ability to fully smell and taste has not yet returned after 14 weeks following her breakthrough case.

Heyer, 55, went in June on a family trip to Utah and began experiencing fever and fatigue. She received a Pfizer vaccine earlier this year but suspected a breakthrough case.

The ultimate test was not being able to smell the garlic in the refrigerator. She then tested positive for COVID-19.

Heyer said she had been careful about always wearing a mask in public and during her trip, but noticed mask-wearing was lax in Utah, including inside of grocery stores.

She said she wouldn’t call the experience mild and never had shortness of breath, Instead, she felt horrible and experienced fever, body aches and extreme fatigue. The illness ranked among her worst flu experiences.

She isolated, eventually recovered and was able to fly home.

“I have new respect for this virus,” she said. “I’ve been telling all my friends you still got to be careful, but I feel incredibly lucky to have gotten vaccinated. I kind of shudder at the thought of how it would have been had I gotten this virus without being vaccinated, so I’m incredibly grateful.”

Every morning, Heyer said, she makes a cup of coffee with the hopes of being able to fully smell the brew again. She also stops to smell plumeria flowers, hoping to one day appreciate their fragrance again.

Lisa Crosby-Torres, 61, is still coping with the aftereffects of the breakthrough cases she and her husband, Pat, who suffers from Parkinson’s disease, experienced while he was hospitalized.

In late August, Crosby- Torres said, her husband fell from the top of the stairs at home and ended up with serious cuts and a traumatic head injury.

He was initially taken to the emergency room at Adventist Health Castle for treatment, then transferred to Kaiser Moanalua Medical Center. There he was moved around several times due to crowded conditions, and eventually shared a room with another patient, who hacked and coughed.

Then she got a call that he may have been exposed to the virus. An initial test came back negative, but a subsequent one was positive. Fortunately, his symptoms were mild, but it prolonged his hospital stay.

She also tested positive and isolated at home for 10 days. Her symptoms ranged from a sore throat to congestion, headaches and fatigue. It was like a moderate cold, she said, with a lot of fatigue toward the end.

Crosby-Torres was grateful that both received the Pfizer vaccine this year. Having asthma, she believes it would have been much worse if she had not been vaccinated.

But the experience was harrowing and took a toll on her husband, who is back home and battling late-stage Parkinson’s.

Crosby-Torres believes it was a mistake for the hospital to place her husband in a room with a patient exhibiting symptoms. Crosby- Torres hopes it does not happen to anyone else.

Kaiser Permanente Hawaii declined to comment on the case, citing patient privacy.

Dr. Tarquin Collis, Kaiser’s chief of infectious disease, said all patients are tested for COVID-19 upon admission. In addition, patients are asked to wear a mask when others are in the room.

Since July, he said, Hawaii has experienced an extremely high level of community spread fueled by the delta variant.

“One of the great challenges of the delta variant is that it is much more infectious than other variants — this is why it has successfully outcompeted every other variant at this point in the outbreak,” Collis said in a statement. “Even patients who are vaccinated can develop breakthrough infections with delta, though this is relatively uncommon; and, if they do have a breakthrough, vaccinated patients are still able to transmit delta to others, though probably at a lower rate than if they were unvaccinated.”

Still, he said, vaccination clearly decreases the risk of infection substantially and helps decrease the risk of hospitalization and death.

“Though no vaccine is perfect, vaccination is the clearly best way to fight this pandemic,” he said.

Anyone who develops symptoms and believes they are a breakthrough case should get tested and quarantine until they get results. If positive, they should follow isolation guidelines.

BREAKTHROUGH CORONAVIRUS CASES

>> The top five symptoms in a breakthrough case are sore throat, congestion, headache, fatigue and loss of smell and taste.

>> If you are symptomatic, get tested. Quarantine until you have the results. If positive, isolate for at least 10 days. People with vaccine breakthrough infections could spread COVID-19 to others.

>> The best ways to prevent a breakthrough are to continue wearing a mask, avoid large gatherings and wash your hands.

Source: CDC; Dr. Zamir Moen, chief of staff, Kaiser Moanalua Medical Center