Public Health Surveillance of Long COVID in Minnesota
Additional details on survey/study methods and measures.
Minnesota Behavioral Risk Factor Surveillance Survey (BRFSS) 2023, 2025
Sample
Observational cross-sectional survey. Representative sample of non-instutionalized Minnesotans aged 18 years and older. 2023 (n=15,740); Response rates (landline=56%; cell=25%); 2025 (n=14,821); Response rates (landline=50%, cell=40%).
Measures
1) Have you ever tested positive for COVID-19 (using a rapid point-of-care test, self-test, or laboratory test) or been told by a doctor or other health care provider that you have or had COVID19?
2) Do you currently have symptoms lasting 3 months or longer that you did not have prior to having coronavirus or COVID-19? (Long term conditions may be an indirect effect of COVID 19. Read if necessary: - Tiredness or fatigue - Difficulty thinking or concentrating or forgetfulness/ memory problems (sometimes referred to as “brain fog”) - Difficulty breathing or shortness of breath - Joint or muscle pain - Fast-beating or pounding heart (also known as heart palpitations) or chest pain - Dizziness on standing -menstrual changes - Symptoms that get worse after physical or mental activities -Loss of taste or smell.)
3) Do these long-term symptoms reduce your ability to carry out day-to-day activities compared with the time before you COVID-19?
Analyses
1) Prevalence estimates are weighted to account for complex sampling and standardized to the U.S. civilian, noninstitutionalized population based on 2020 U.S. Census Bureau population.
2) Sex-specific weights by age group were applied for ages 18-44, 45-64, and ≥65 years.
3) Denominators for prevalence estimates of current Long COVID are the total adult population.
4) Denominators for prevalence estimates for significant activity limitation are the number of adults with current Long COVID.
Reference
https://www.cdc.gov/brfss/index.html
Minnesota Post-COVID Cross-Sectional Survey 2023
Sample
Observational cross-sectional survey. Sample of 26,815 confirmed SARS-Cov-2 cases reported to the Minnesota Department of Health from January 1, 2021, through December 31, 2022, and aged 18 years or older; 6,475 contacted (24%), 1,597 completions (5%).
Measures
1) After your COVID-19 infection, did you have any symptoms that lasted longer than one month?
2) Now we would like to know about symptoms that lasted a month or longer after a COVID-19 infection OR new symptoms that may have started a month or longer after your COVID-19 infection? (Series of 35 symptom-specific measures such as anxiety, brain fog, change in taste or smell, fatigue, shortness of breath when resting, etc.)
3) Within the past 30 days, how much difficulty do you have with the following activities? (List of 12 daily activities)
Analyses
Unadjusted descriptive analyses were conducted.
Reference
Long COVID Data and Reports - MN Dept. of Health; jay.desai@state.mn.us
Minnesota Longitudinal Post-COVID Survey 2025
Sample
Longitudinal cohort survey at baseline and 1, 3, 6, 12, and 18 months. MDH confirmed SARS-Cov-2 cases from October 1, 2024-February 15, 2025, in persons ≥5 years old (parent or guardian completed survey as needed), excluding long-term care facility residents; 3,513 cases contacted, 1,097 completed baseline survey (31%), 823 enrolled in follow-up surveys (59-68% response rate at FUP periods).
Measures
1) Next, I'm going to ask you about ongoing, or persistent symptoms that may have started or worsened since your COVID-19 infection. If you experienced a symptom before your recent COVID-19 infection, please only answer 'yes' if the symptom is significantly worse now? (If no, extra clarification provided: Even though you answered that you aren't experiencing new or worsening symptoms that are impacting your ability to carry out daily activities, I'm going to ask about some specific symptoms. Please answer yes to any symptoms that may have started or worsened since your COVID-19 infection. If you experienced a symptom before your recent COVID-19 infection, please only answer yes if the symptom is significantly worse now; series of 15 symptom-specific measures such as anxiety, brain fog, change in taste or smell, fatigue, shortness of breath when resting, etc.).
2) Are you currently experiencing any ongoing or persistent symptoms that began or significantly worsened since your recent COVID-19 infection and are reducing your ability to carry out daily activities? Examples of daily activities include work, volunteering, going to school, doing housework or light chores, or taking part in organized activities.
Analyses
Unadjusted descriptive analyses were conducted.
Reference
Contact jay.desai@comcast.net for more information.
Minnesota Electronic Health Record Consortium (MNEHRC) Post-COVID Conditions Study
Sample
Eligibility: Patients (all ages) who received care between January 1, 2017- December 31, 2024, with at least one documented SARS-CoV-2 or influenza (contemporary comparison) PCR test.
Historic comparison: Patients with a total cholesterol value <200 mg/dL between January 1, 2017-June 30, 2018. Patients had at least one recorded health care visit after June 30, 2015, and prior to the index test (SARS-CoV-2, influenza, or cholesterol) date. Only Minnesota residents were included. Patients who died within 30 days of the index test were excluded from all analyses.
The study population included 1,420,487 patients who had only negative SARS-CoV-2 results, 448,595 patients who had only one positive SARS-CoV-2 result, 2,718,858 patients with a negative influenza result, 307,526 with a positive influenza result, and 99,445 patients with a total cholesterol <200mg/dL who had a total cholesterol test.
Measures
Post-COVID conditions were evaluated using the CDC Track Post-COVID Conditions (Track PCC) EHR-based case definition of 49 post-COVID conditions. A patient was classified as having PCC if a condition was not present prior to the index test but was present between 30 and 548 days following the index test date. A narrow long COVID definition examined patients with a new ICD-10-CM U09.9 or G93.2 code after a positive SARS-Cov-2 test.
Analyses
Descriptive statistics, including counts and proportions, were used to characterize the study cohort. Counts and percentages of patients with positive and negative tests and PCC within each test group were calculated.
Reference
Jones, R. M., Andrews, J. G., Dalton, A. F., Dixon, B. E., Dzomba, B. J., Fernando, S. I., Pogreba-Brown, K. M., Ortiz, M. R., Sharma, V., Simmons, N., Saydah, S. H., & Track PCC Study Group (2024). Tracking the burden, distribution, and impact of Post-COVID conditions in diverse populations for children, adolescents, and adults (Track PCC): passive and active surveillance protocols. BMC public health, 24(1), 2345. https://doi.org/10.1186/s12889-024-19772-4
Contact jay.desai@comcast.net for more information.
