Vaccine Breakthrough Data: COVID-19 Situation Update- Minnesota Dept. of Health

COVID-19 Vaccine Breakthrough Data COVID-19 Situation Update


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Updated 9/29/2022
Updated weekly on Thursdays at 11 a.m. with data as of 4 a.m. on the Tuesday prior, unless noted otherwise.

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COVID-19 vaccines are effective. However, some people who are vaccinated will still get COVID-19 if they are exposed to the SARS-CoV-2 virus. These are called "vaccine breakthrough cases." Vaccination can make illness less severe in people who experience a vaccine breakthrough infection. Fully vaccinated people are also much less likely to be hospitalized or die than people with similar risk factors who are not vaccinated. People who have received booster doses have an even lower risk of hospitalization or death than people with similar risk factors who have only received a primary series of vaccine or people who are not vaccinated.

On this page:
Background & Case Definition
COVID-19 Vaccine Breakthrough Data
   Adult Vaccine Breakthrough Data
   Pediatric Vaccine Breakthrough Data
   Making Direct Comparisons in Raw Case, Hospitalization, and Death Counts
Information for Case Investigation and Reporting

Background & Case Definition

Vaccine breakthrough after primary series:

A confirmed or probable SARS-CoV-2 infection occurring 14 or more days after a person has completed the primary series of an FDA-authorized or approved COVID-19 vaccine. The primary series requires one dose of vaccine for the Janssen (Johnson & Johnson) vaccine or two doses for the Pfizer or Moderna vaccines.

Vaccine breakthrough after booster vaccination:

A confirmed or probable SARS-CoV-2 infection occurring 14 or more days* after a person has received an additional or booster dose for an FDA-authorized or approved COVID-19 vaccine. Additional or booster doses must have been received on or after 8/13/2021, based on when the FDA first authorized additional or booster doses beyond the primary series.

*The 14-day lag for booster doses aligns with the case definition for vaccine breakthrough in a boosted person used in the CDC: COVID Data Tracker.

More about cases can be found in Cases & Variants.

About COVID-19 Vaccine Breakthrough Data

When reviewing vaccine breakthrough data, there are several important things to know:

  • Vaccines are doing their job – they are highly effective preventing severe disease, hospitalization, and death.
  • As more people become vaccinated it is natural to see more cases of vaccine breakthrough (no vaccine is 100% effective).
  • We may be seeing more vaccine breakthrough cases for many reasons including:
    • Waning immunity as more time passes from when people have received their most recent dose of COVID-19 vaccine.
    • Variants that spread more easily may be playing a role.
    • People are returning to various states of normalcy – this will result in varying levels of disease transmission and test seeking behaviors.
  • Vaccination records may be incomplete as a result of reporting errors and delays or problems matching vaccination information with case data. In addition, some entities, including federal organizations, don't report vaccination information to the state.
  • Breakthrough infection is not the same thing as breakthrough disease. Breakthrough infections occur any time a fully vaccinated person tests positive for COVID-19, regardless of whether they feel sick. This data report is on breakthrough infections, not breakthrough disease.
  • Vaccine breakthrough data are not the same as vaccine effectiveness data. To determine vaccine's effectiveness, you need to be able to control for factors that may influence who becomes a COVID-19 case and who does not. We are not able to do that with vaccine breakthrough data. For more information on studies on vaccine effectiveness:  CDC: COVID-19 Vaccine Effectiveness Research.
  • At times, some breakthrough infection rates may appear equal or higher for people who are fully vaccinated. There are several reasons that this can happen, and some important things to keep in mind when interpreting the data:
    • For shorter time periods, like the "last 60 days," when there are low case rates overall the data can be more significantly impacted by even a few cases. It does not mean the data are wrong or vaccine are not working. When you look at longer time periods or periods with higher case rates, you see the trend that vaccines are working to reduce hospitalizations and deaths.
    • We are still learning about the relationship between new variants and vaccine breakthrough infection, especially for 5-11-year-olds since they were able to get vaccinated right when the Omicron variant surge started.
    • There are differences between the vaccinated and unvaccinated populations, such as when they decide to get tested, which can make it more likely to find cases in certain groups. People with underlying health conditions who are at higher risk for a vaccinate breakthrough infection may be more likely to get vaccinated because of their health condition.

What Are Vaccine Breakthrough Cases Video

COVID-19 Vaccine Breakthrough Data

All data is preliminary and may change as cases are investigated. Case and vaccine totals reflect only the results from laboratory testing and vaccinations that have been reported to the Minnesota Department of Health.

Data may not align exactly with the cases reported on other pages or dashboards due to differences in reporting lags and the frequency with which the data are updated.

  • Fully vaccinated: A person is considered "fully vaccinated" if they have received the complete primary series of their vaccine AND at least 14-days have passed since they have completed their primary series AND if they are an adult, they have not received any additional/booster doses beyond their primary series.
  • Not fully vaccinated: A person is considered "not fully vaccinated" if they have not completed a primary series of vaccine. This includes people who have not received any vaccine, people who have received only one dose of vaccine in a two-dose series, and people for whom it has not yet been 14 days since they completed their primary series.
  • Boosted: A person is considered "boosted" if they have received any additional doses of vaccine beyond their primary series AND it has been at least 14 days since their most recent dose of vaccine. People for whom it has not been at least 14 days since their booster dose are considered "fully vaccinated." Booster doses are only counted if they were administered on or after 8/13/2021, the date the CDC first began recommending booster doses for immunocompromised people.
  • Total population that is not fully vaccinated: Estimates of the unvaccinated population are obtained by subtracting the number of Minnesotans known to have received at least a primary series of vaccine (including those who have received boosters) from the 2019 American Community Survey (ACS) 5-year Estimates by age for Minnesota at United States Census Bureau: Explore Census Data. Statewide estimates by age are based on ACS tables DP05 and S0101, except for the 5-11- and 12–15-year-old age groups, which are based on summing the county-level estimate based on ACS table B01001. The 5-11- and 12-15-year age groups have been split based on the assumption that ages are equally distributed within age groups.
  • Total population that is fully vaccinated or boosted: Data for the total number of Minnesotan's who are fully vaccinated or boosted are obtained from the Minnesota Immunization Information Connection (MIIC).
  • COVID-19 hospitalization: Includes patients admitted to the hospital for any reason within 14 days of a positive COVID-19 test.
  • COVID-19 death: Deaths with a positive COVID-19 test AND either COVID-19 is listed on the death certificate OR clinical history/autopsy findings provide evidence that the death is related to COVID-19 without an alternative cause (e.g., drowning, homicide, trauma, etc).
  • Rate per 100,000: Incidence rates per 100,000 are calculated as the number of people in each age group with a positive COVID-19 test (or hospitalization or death) who have not received a primary COVID-19 vaccination series (or who have received only primary series or a primary series + booster), divided by the total number of people in Minnesota in that age group who have not received a primary COVID-19 vaccine series (or who have received only a primary series, or who have received a primary series + booster) multiplied by 100,000.
  • Age-adjusted rates: Weekly age-adjusted rates per 100,000 are obtained by taking the incidence rate per 100,000 and standardizing to the U.S 2000 Standard Population which can be obtained from the National Cancer Institute: Standard Populations (Millions) for Age-Adjustment.
  • Incidence rate ratio: Incidence rate ratios are calculated by dividing the incidence rate among people who are not fully vaccinated by the incidence rate among people who are fully vaccinated (or by people who are fully vaccinated and boosted).

Adult (age 18+) Vaccine Breakthrough Data

Adult Age Adjusted Cases, Hospitalizations, and Deaths by Vaccination Status

  • Adult Age-Adjusted Cases, Hospitalizations, and Deaths Data File (CSV)
  • Age-adjusted rates for people who are boosted begins on the week beginning 10/10/2021, two weeks after the CDC expanded booster recommendations to the majority of the U.S. adult population.
  • Fully vaccinated and boosted populations are mutually exclusive, a vaccine breakthrough infection is only counted in one of the two groups.

Adult Cases, Hospitalizations, and Deaths by Age Group

  • Adult Cases, Hospitalizations, and Deaths by Age Group Data File (CSV)
  • Booster vaccinations are only counted beginning the week that starts on 10/10/2021, two weeks after the CDC expanded booster recommendations to the majority of the U.S. adult population. Time period filters that begin earlier than 10/10/2021 will still show information about booster data but the data used to calculate these rates does not begin before 10/10/2021.

Pediatric (ages 5-17) Vaccine Breakthrough Data

Pediatric Cases and Hospitalizations by Vaccination Status

  • Pediatric Age Adjusted Cases and Hospitalizations by Vaccination Status Data File (CSV)
  • Data for ages 12-17 are included in the age adjusted rate calculations starting 7/4/2021. Data for ages 5-11 are not included in the age adjusted rate calculations until 12/05/2021 to account for the time it would take from when vaccines were first authorized for the 5-11 age group (10/29/2021) plus 21-days to allow for completion of the primary series, plus an additional 14 days to align with the case definition for a vaccine breakthrough infection.
  • Pediatric deaths are not reported by vaccination status.

Pediatric Cases and Hospitalizations by Age Group

  • Pediatric Cases and Hospitalizations by Age Group Data File (CSV)
  • Data for ages 12-17 are included in the age adjusted rate calculations starting 7/4/2021. Data for ages 5-11 are not included in the age adjusted rate calculations until 12/05/2021 to account for the time it would take from when vaccines were first authorized for the 5-11 age group (10/29/2021) plus 21-days to allow for completion of the primary series, plus an additional 14 days to align with the case definition for a vaccine breakthrough infection.

Making Direct Comparisons in Raw Case, Hospitalization, and Death Counts

  • Notes about making direct comparisons between the number of people vaccinated with a primary series (or a primary series + booster) and people without a primary series:
    • There are differences in the population of people who are vaccinated with a primary series or vaccinated with a primary series + booster and the population of people who are not vaccinated with a primary series.  For example, Minnesotans who are older, have underlying health conditions, or work in high-risk settings are more likely to have a primary series and more likely to have gotten their booster shots.
    • This means more people in the vaccinated with a primary series and vaccinated with a primary series + booster populations are at increased risk of developing, becoming hospitalized, or dying from COVID-19 because of their age, health conditions, or types of exposures.
    • Because the populations are different, you must make adjustments in order to directly compare them.
    • Making comparisons without these adjustments does not provide a measure of how well the vaccine works.
    • For more information, please watch What Are Vaccine Breakthrough Cases.

Information and Resources for Case Investigation and Reporting

Updated Wednesday, 28-Sep-2022 17:10:36 CDT