COVID-19 Primary Series and Booster Vaccination - Minnesota Dept. of Health
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For Health Care Providers
COVID-19 Primary Series and Booster Vaccination

Completing all recommended COVID-19 vaccine doses is important

Vaccination with COVID-19 vaccines currently approved or authorized by the Federal Drug Administration (FDA) has been shown to prevent infection, severe disease, hospitalization, and death caused by coronavirus disease 2019 (COVID-19). Efforts to increase the number of people who are up to date with the recommended COVID-19 vaccine doses will assist in preventing these serious outcomes. For considerations with being up to date on COVID-19 vaccinations, refer to CDC: Stay Up to Date with Your COVID-19 Vaccines.

Primary series

Second dose

It is important for people to receive both doses of any COVID-19 vaccine that requires two doses, and in general, both doses should be the same vaccine product. In situations where the product used for the person's first dose is not available, providers may administer a different product to avoid missed opportunities and complete the primary series. Refer to CDC: Interchangeability of COVID-19 vaccine products for additional details. mRNA COVID-19 vaccines are preferred over the Johnson & Johnson (Janssen) vaccine except in limited situations.

Intervals between the first and second dose depends on the vaccine product, the person's age, and if the person is immunocompromised. An 8-week interval between primary series doses may be optimal for people ages 12 to 64, particularly males age 12 to 39. A longer interval may increase the effectiveness of the vaccine and minimize the small risk of myocarditis and pericarditis. A shorter interval (3 weeks for Pfizer-BioNTech; 4 weeks for Moderna) remains recommended for people who are ages 5-11 years, 65 years and older, moderately or severely immunocompromised, or need to develop protection quickly because of high CDC: COVID-19 community levels.

Providers should refer to CDC: Interim Clinical Considerations for Use of COVID-19 Vaccines: Recommendations and schedule to understand the interval between each dose for COVID-19 vaccine products that require more than one dose for a primary series.

Additional primary series dose of mRNA vaccine for immunocompromised people

CDC recommends that people with certain immunocompromising conditions get an additional dose of an mRNA vaccine as part of their primary vaccine series. If the person received their initial vaccination with an mRNA vaccine, the same vaccine product should also be used for the additional dose. If the person received a Johnson & Johnson (Janssen) vaccine for their initial primary series dose, they should receive a second dose of an mRNA vaccine. Refer to CDC: Guidance for COVID-19 vaccination for people who are moderately or severely immunocompromised for details on the recommended vaccination schedule.


COVID-19 vaccines continue to work very well at reducing the risk of severe illness, hospitalization, and death, but data suggest that protection against COVID-19 infection decreases over time. At least one booster dose is recommended for most people. The recommended interval between the primary series and the booster dose is based on the vaccine product and if the person is immunocompromised. For details on booster dose schedules, refer to CDC's Recommendation and schedule and People who are moderately or severely immunocompromised.

Some people, including people ages 50 years and older, people who are immunocompromised, or people who have received two doses of the Johnson & Johnson (Janssen) vaccine, may receive a second booster dose. For considerations on the timing of this booster dose, visit CDC: Clinical Considerations: Second COVID-19 Vaccine Booster Dose (PDF).

Vaccination reminders

Vaccination reminders are critical to ensure compliance with vaccine dosing intervals and to achieve optimal vaccine effectiveness.

Use these tips for COVID-19 vaccine reminders:

  • Use reminder/recall systems through MIIC or your electronic health record (her). In MIIC, utilize the Client Follow-Up (CFU) feature to learn which of your clients are recommended/overdue for vaccine. For user guidance on CFU in MIIC, please visit Client Follow-Up MIIC User Guidance and Training Resources.
  • Partner with MDH to text your clients who are recommended or overdue for COVID-19 vaccine. The process of getting this activity set up and implemented is very simple and the maintenance is automated. MDH has successfully implemented texting with several organizations. Please reach out to the MIIC Help Desk to get started. For more information refer to Reminder/Recall Using Text Messages (PDF).
  • Make sure each person getting vaccinated knows how long they must wait in between their vaccinations.
  • Make every attempt to schedule the next dose appointment at the time of the first dose, or schedule both appointments when scheduling the first appointment.
  • Complete a COVID-19 vaccination record card (vaccine manufacturer, lot number, date of dose received, and the date the next dose is due) for each person who is vaccinated. Encourage them to keep the card and bring it to the next dose appointment.
  • If the patient has a smartphone, ask them to:

Sign-up for MDH COVID-19 vaccine provider email updates:
Updated Wednesday, 01-Jun-2022 09:33:22 CDT