Here’s how many Utahns are known to have been infected with COVID-19 after vaccination

Of more than 520,000 fully vaccinated Utahns, 96 have been infected afterward.

When Christie Griffith started feeling ill a couple of weeks ago, she assumed it couldn’t be the coronavirus. As a nurse at Alta View Hospital in Sandy, she had been vaccinated in January.

But then her husband, who had received only his first shot and also was feeling ill, noticed he couldn’t smell a stick of gum. She couldn’t smell it either.

Sure enough, the next morning she tested positive for COVID-19.

Griffith is one of 96 Utahns who have contracted the virus after being fully vaccinated — defined as more than two weeks after their final doses.

“We call these ‘breakthrough cases,’” said Tom Hudachko, spokesman for the Utah Department of Health. “... With 521,686 people fully vaccinated as of Thursday, only 96 breakthrough cases indicates the COVID-19 vaccine is tremendously effective.”

The Pfizer vaccine, which Griffith received, is 95% effective at preventing COVID-19, while Moderna was 94.1% effective in trials, the Centers for Disease Control and Prevention reports. Federal researchers this week confirmed the effectiveness of the vaccines, with follow-up studies showing those vaccines to be about 90% effective.

“The Pfizer vaccine is very effective but it’s not 100% effective; everybody knows that,” said Griffith’s husband, Bryan. “So somebody has to get sick after getting a shot. Somebody has to be the other 5%. I don’t know if we happened to get a supervariant or just bad luck or whatever.”

Breakthrough cases remain rare. Out of 1 million fully vaccinated people in Washington state, for example, epidemiologists found evidence of 102 breakthrough cases since Feb. 1, the state’s health department said March 30. A week earlier, researchers reported two studies in the New England Journal of Medicine that showed a handful of health care workers had been infected after vaccination, out of thousands tracked and tested.

The question of variants

Griffith’s sample is undergoing genomic sequencing to learn whether she contracted a variant of the virus. Any patient whose “breakthrough” case was identified with a PCR test — as opposed to a rapid antigen test — has a sample collected for genomic sequencing, said Ilene Risk, epidemiologist for the Salt Lake County Health Department.

So far, only two of Utah’s 96 breakthrough cases have been confirmed to be a variant strain of the virus, Hudachko said. But those are the only two for which genomic sequencing has been completed; 39 samples were still pending at the lab as of Thursday, and the other 55 were antigen tests that can’t be sequenced.

Risk noted that lab work still is pending for all 11 of Salt Lake County’s known breakthrough cases.

“It does take the state lab a little bit of time,” Risk said, “since they’re also sequencing random samples, hospitalized cases, those we suspect are variants, and other breakthrough cases as well.”

In all, about 3% of Utah’s positive cases are undergoing sequencing. In the past four weeks, the so-called U.K. variant — B.1.1.7 — has accounted for about 2.6% of all the samples that were sequenced, Hudachko said. However, that’s from a relatively small number of samples.

“The one thing we do know is that the number of variants we are detecting is going up,” Hudachko said. “This means that variants are spreading in Utah, especially B.1.1.7.”

But it’s not known whether any of the variants are more likely to escape the vaccine’s protections. Instead, the vaccines may simply activate a less-powerful immune response in some people than in others.

“There’s a lot of heterogeneity with the antibody response with this vaccine,” Risk said.

‘Like ... a head cold’

Although she was disconcerted to test positive after being vaccinated, Griffith said there’s no telling how much sicker she might have gotten without the vaccine.

“I’m sure it probably made my symptoms less severe,” she said. “It just felt like I had a head cold.”

The majority of Washington state residents who had confirmed breakthrough coronavirus cases experienced only mild symptoms, if any, state health officials said.

While Utah officials aren’t counting an infection as a “breakthrough” case if the patient has had just one of two doses of vaccine, partially vaccinated people do have some protection — and Salt Lake County is tracking the vaccine histories of patients who are hospitalized, noting where they have had at least one shot.

As of Monday, there had been 43 Salt Lake County patients who had been hospitalized for symptoms that possibly were due to COVID-19, even though they had received one dose of vaccine, Risk said.

However, while those patients had tested positive for COVID, health officials had not ruled out other possible reasons for hospitalizations in those 43 cases. And none of them was fully vaccinated.

For Griffith, the protection against serious illness for those who are fully vaccinated means she can envision a time when COVID-19 is seen as no more threatening than the head cold symptoms she had for about a week in March — even if some people still get it.

“I’ve got to believe that the scientists that worked so hard to get it out to us know what they’re doing,” Griffith said. “I would still encourage people to get it.”