© 2023 Boise State Public Radio
NPR in Idaho
Play Live Radio
Next Up:
0:00 0:00
Available On Air Stations

Idaho Is Tracking Rare “Breakthrough” COVID-19 Cases

Russell Tate
United Nations COVID-19 Response

Idaho is tracking some COVID-19 cases among people who are fully vaccinated. 




Of the more than 270,000 people in the state who’ve been fully vaccinated, there have been 97 confirmed COVID-19 infections. Those people tested positive at least two weeks after receiving their final vaccine dose. 


“Breakthrough” cases, as they’re called, are both very rare and expected, as the COVID-19 vaccines, like all other vaccines, are not 100% effective – though they’re very close. 


A study released by the Centers for Disease Control and Prevention this week found the Pfizer and Moderna mRNA vaccines to be 90% effective at preventing COVID-19 infections among health care workers and frontline personnel who had received both doses. These vaccine companies also reported higher than 90% efficacy numbers from clinical trials. 


The 97 infections account for roughly .035% of Idahoans who have been fully vaccinated. 


Deputy State Epidemiologist Dr. Kathryn Turner said about half of the cases have been asymptomatic. They might’ve been tested for COVID-19 because of mandatory screenings at work or school settings, or because they’d been exposed to someone who tested positive. The people who have had symptoms have not been very sick, Turner said.


“Among the people who did experience illness, 80% of them had either very mild symptoms, so this would be something similar to allergy symptoms, or maybe a head cold, or they experienced moderate illness,” she said during a media briefing on Tuesday. 


Three of those 97 have been hospitalized, and they all had serious pre-existing medical conditions. 


Turner said the state is trying to sequence as many of these cases as possible to see if they might be any of the new variants. Only three of these breakthrough infections have been identified as new variants, and they were all the ‘California variant.’ 

Find reporter Rachel Cohen on Twitter @racheld_cohen  

Copyright 2021 Boise State Public Radio

As the south-central Idaho reporter, I cover the Magic and Wood River valleys. I also enjoy writing about issues related to health and the environment.

You make stories like this possible.

The biggest portion of Boise State Public Radio's funding comes from readers like you who value fact-based journalism and trustworthy information.

Your donation today helps make our local reporting free for our entire community.