COVID-19 Vaccine Breakthrough Weekly Update

Updated May 9, 2022
Updated weekly, on Mondays at 11 a.m.

COVID-19 vaccines are effective. However, some people who are fully vaccinated will still get COVID-19 if they are exposed to the virus that causes it. These are called "vaccine breakthrough cases." We are tracking vaccine breakthrough cases in Minnesota and monitoring trends.

Vaccination can make illness less severe in people who get vaccinated but still get sick. Fully vaccinated people are also much less likely to be hospitalized or die than people with similar risk factors who are not vaccinated.

On this page:
Background & Case Definition
COVID-19 Vaccine Breakthrough Data
Information for Case Investigation and Reporting
Other Information, Data, and Statistics

Background & Case Definition

A vaccine breakthrough infection occurs when a confirmed or probable SARS-CoV-2 infection occurs 14 or more days after a person has completed all the recommended doses of their COVID-19 vaccine (not including boosters).
More about confirmed and probable cases, positive people, and reinfections can be found in the Minnesota Case Overview.

COVID-19 vaccine breakthrough cases are identified by actively matching Minnesota case records with Minnesota vaccination records. MDH also takes and follows up on reports from health care providers, long term care, and correctional facilities. A vaccine breakthrough event could happen more than once for a person.

About COVID-19 Vaccine Breakthrough Data

There are multiple points to consider when reviewing vaccine breakthrough data:

As more people become vaccinated it is natural to see more cases of vaccine breakthrough (no vaccine is 100% effective). However, vaccines remain highly effective at preventing severe disease, hospitalization, and death.
Vaccinated people should still take steps to protect themselves and others in certain settings such as indoor public settings and crowded outdoor areas.
We may be seeing more vaccine breakthrough cases for many reasons including:
- Waning immunity among people vaccinated earliest. These people are also more likely to be older, have comorbidities, or work in a setting that puts them at higher risk for COVID-19.
- The more-transmissible Delta variant may be playing a role that we don’t fully understand yet.
- 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 the SARS-CoV-2 virus, regardless of whether they feel sick. This data report is on breakthrough infections, not breakthrough disease.
Vaccine breakthrough is not a measure of efficacy. There are several studies on vaccine effectiveness:  CDC: COVID-19 Vaccine Effectiveness Research.

What Are Vaccine Breakthrough Cases Video

Other languages: What Are Vaccine Breakthrough Cases

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.

Case Overview

Total number of fully vaccinated Minnesotans age 5 and older (as of the week beginning 3/27/2022)*	3,684,343

	Number of vaccine breakthrough cases	Percent of fully vaccinated people
Total cases	399,389	10.840%
Total cases hospitalized**	11,513	0.312%
Total deaths***	2,064	0.056%

More about Vaccine Breakthrough Data

* Fully vaccinated means that at least 14 days have passed since a person completed their COVID-19 vaccination series. A complete series can mean 1 or 2 doses of vaccine have been given, depending on the product. The number of fully vaccinated people will not be the same as the number with a complete vaccination series found on COVID-19 Vaccine Data. Case reporting and vaccine reporting have delays in addition to the time it takes to match case data to the Minnesota Immunization Information Connection. Case counts will typically reflect cases reported one or more weeks ago. Note: As of 2/14/2022 Total number of fully vaccinated Minnesotans now includes people age 5-11 years old.
** Total cases hospitalized includes patients admitted for any reason within 14 days of a positive SARS-CoV-2 test.
*** Total deaths (also known as total deaths with laboratory testing) are deaths due to COVID-19 with a positive PCR test (confirmed case) or antigen test (probable case) for SARS-CoV-2, and either COVID-19 is listed on the death certificate or clinical history/autopsy findings that provide evidence that the death is related to COVID-19 without an alternative cause (e.g., drowning, homicide, trauma, etc).

The case overview data above covers a longer time period than the cases, hospitalizations and deaths tables and graphs below. The case, hospitalization, and deaths data below begins at a later date to capture the time frame when the majority of Minnesotans were eligible to receive vaccine. 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.

Cases, Hospitalizations, and Deaths Over Time

More about Vaccine Breakthrough Over Time

Cases, Hospitalizations, and Deaths Over Time Data File (Excel)
Data within the lag period may change significantly due to delays in reporting and the need to deduplicate and confirm reports.
Weekly rate per 100,000 people among the vaccinated is calculated as the number of fully vaccinated people who test positive for SARS-CoV-2 (or who are hospitalized after testing positive for SARS-CoV-2, or who died as a result of an infection with SARS-CoV-2) in a given week divided by the total number of people who were fully vaccinated by that week multiplied by 100,000.
Weekly rate per 100,000 people among the not fully vaccinated is calculated as the number of not fully vaccinated people who test positive for SARS-CoV-2 (or who are hospitalized after testing positive for SARS-CoV-2, or who died as a result of an infection with SARS-CoV-2) in a given week divided by the total number of people who were not fully vaccinated by that week multiplied by 100,000.
Age-adjusted rates are used to directly compare mortality and disease risk in two groups that have different age compositions. The age composition of the vaccinated population is different from the age composition of the not fully vaccinated population. For example, the vaccinated population in Minnesota is older than the not fully vaccinated population. Older adults are also at greater risk of developing, becoming hospitalized, or dying from COVID-19. Any population that has more older adults will have a higher risk of COVID-19 disease, hospitalization and death. Age adjustment is necessary in order to accurately compare fully vaccinated people to not fully vaccinated people.
This data only includes individuals age 12 and older.

Cases, Hospitalizations, and Deaths by Age Group

More about Vaccine Breakthrough by Age Group

Cases, Hospitalizations, and Deaths by Age Group Data File (Excel)
Rate per 100,000 person-weeks among the vaccinated is calculated as the number of fully vaccinated people who test positive for SARS-CoV-2 (or who are hospitalized after testing positive for SARS-CoV-2, or who died as a result of an infection with SARS-CoV-2) divided by the total number of person-weeks of fully vaccinated people multiplied by 100,000.
Rate per 100,000 person-weeks among those not fully vaccinated is calculated as the number of not fully vaccinated people who test positive for SARS-CoV-2 (or who are hospitalized after testing positive for SARS-CoV-2, or who died as a result of an infection with SARS-CoV-2) divided by the total number of person-weeks of not fully vaccinated people multiplied by 100,000.
Person-weeks are calculated as the cumulative sum of the total number of people who were fully vaccinated or not fully vaccinated in each week in a given time period.
This data only includes individuals age 12 and older.
Deaths in people age 12-17 are not reported by vaccination status due to the small number of deaths that have occurred in this age group.

Proportion of Fully Vaccinated Cases, Hospitalizations, and Deaths

Vaccine breakthrough cases (VBT) represent the small portion of cases among people who belong to both the group of people who are COVID-19 cases and the group of people who are fully vaccinated. When we consider the proportion of COVID-19 cases that are VBT, we are not including any information about the larger populations of fully vaccinated or not fully vaccinated people in Minnesota.

There are differences in the population of people who are fully vaccinated and the population of people who are not fully vaccinated. For example, the vaccinated population in Minnesota is older, more likely to have comorbidities, and more likely to work in high-risk settings.
- This means more people in the fully vaccinated population are at increased risk of developing, becoming hospitalized, or dying from COVID-19.
- Because the populations are different, you would have to make adjustments in order to directly compare them.
- The charts below do not include these adjustments so this comparison of fully vaccinated and not fully vaccinated cases, hospitalizations, and deaths should not be used as a measure of how well the vaccine works.
- For more information, please watch the “What Are Vaccine Breakthrough Cases” video.

Cases, Hospitalizations, and Deaths Data File (Excel)

More about Proportion of Fully Vaccinated Cases, Hospitalizations, and Deaths

Data presented are crude proportions. They are not adjusted for differences in the fully vaccinated vs. not fully vaccinated populations.
Data are preliminary and subject to change. This is especially true for hospitalizations and deaths which may be reported several weeks after a case is first identified. Attribution of hospitalization to COVID-19 symptoms does not always align or occur in a timely manner. Some hospitalizations may be due to a variety of reasons and patients may have been tested upon admission to the hospital.
This data only included cases age 12 and older for the data range specified.
On 12/6, the name of the data file was changed from Cases, Proportion of Fully Vaccinated Cases, Hospitalizations, and Deaths.

Information and Resources for Case Investigation and Reporting

COVID-19 Vaccine Breakthrough Case Investigation and Reporting
CDC information and resources to help public health departments and laboratories investigate and report COVID-19 vaccine breakthrough cases.
Health Care: COVID-19
Minnesota guidance for reporting, evaluating and testing, infection prevention and control, and more.