COVID-19 Q&A: Breakthrough cases and variants

Q: Are we seeing cases of disease among Idahoans who have been fully vaccinated against COVID-19? How many of those people have been hospitalized? Have there been any deaths?

A: We have seen some “breakthrough cases,” which is the term being used to refer to people who have been fully vaccinated, but who have been infected with the virus that causes COVID-19.

Breakthrough cases are expected since no vaccine offers 100 percent protection against illness. COVID-19 vaccines are the best protection we have against serious illness and death, in addition to the recommended guidelines. And the data bears that out. The good news, so far, is that people who develop COVID-19 after being fully vaccinated have experienced mostly mild to moderate illness.

Of the 105 cases reported as of today, only three have had to be hospitalized, and there have been no deaths. The three who were hospitalized had medical conditions that increased their risk for serious illness.

Q: Have all the samples for the breakthrough cases been sequenced to determine if they were caused by variants of public health concern?

A: We are trying to sequence as many of these as possible, but sometimes all samples from the patient have already been discarded, or we are simply not able to get enough of the virus to sequence.

Of the 105 vaccine breakthrough cases that have been reported, 16 samples have been sequenced. Of those, four have been a variant of public health concern, all the strain that was first detected in California.

Q: Are the COVID-19 vaccines effective against the variants?

A: The vaccines currently available in the United States all appear to offer adequate protection against serious illness and hospitalization from the currently known variant strains of public health concern. But as the virus spreads and mutates further, there may be a need for a booster dose of the vaccine at some point. This is being monitored closely by public health agencies and the manufacturers.

Q: How is whole genome sequencing being done in Idaho to determine variants of public health concern? 

A: DHW’s Idaho Bureau of Laboratories (IBL) has been sequencing samples from Idaho for a little more than a month now. IBL has requested that all clinical laboratories performing PCR testing for COVID-19 in Idaho to send up to five samples each week to be sequenced to IBL.

Samples from all parts of the state have been sequenced; however, sequencing data are not representative of all the virus variants circulating in the state because many samples are coming from high priority populations. These priority populations include people in congregate living settings, people who are part of a local outbreak, and people with a high suspicion for potential variants of concern, such as those who have recently traveled.

DHW is working to increase the number of Idaho labs that can sequence samples from patients who have tested positive for the virus that causes COVID-19. We’ve applied for federal funding to help enhance testing at the University of Idaho Genomics Resource Center to provide additional capacity in northern Idaho, and we’re supporting the Boise Veteran’s Affairs Medical Center as they bring their sequencing program online. 

The Centers for Disease Control and Prevention (CDC) is coordinating a national effort to perform sequencing on a random sampling of positive samples identified by laboratories around the country. They are currently sequencing about 18,000 samples per week nationwide. The goal is to sequence 25,000 samples per week.

We don’t know how many of those samples are from Idaho as they are being submitted, but we are notified of any variant detections and the total samples sequenced once they are completed.  

All Idaho samples, regardless of where they were sequenced, have the sequences uploaded into public databases. We are tracking and reporting on those publicly available Idaho sequences weekly on case data dashboard at the

Idaho posts updated information about variants each Thursday under the Laboratory Testing page on the state’s data dashboard for COVID-19 cases, available at:!/vizhome/DPHIdahoCOVID-19Dashboard/Home

Dr. Kathryn Turner is the deputy state epidemiologist in the Department of Health and Welfare’s Division of Public Health.

Join us at 10 a.m. Wednesday on Facebook Live: Deputy state epidemiologist Dr. Kathryn Turner will answer questions about coronavirus variants of public health concern and breakthrough cases and will take questions from viewers.

To slow the spread of COVID-19 in Idaho, please continue to:

  • Wear face coverings  
  • Keep at least six feet between you and others
  • Stay home if you are sick
  • Wash your hands often
  • Cover coughs and sneezes
  • Disinfect surfaces and objects regularly


Stay up-to-date with the latest and most accurate information on COVID-19 at the following websites:

DHW also posts lots of information, including daily updates on the numbers on Twitter, Facebook, and Instagram.

The Idaho Department of Health and Welfare is dedicated to strengthening the health, safety, and independence of Idahoans. Learn more at

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