brand logo

This supplement is sponsored by the American Academy of Family Physicians. The project has been made possible by the Centers for Disease Control and Prevention. 

Fam Pract Manag. 2023;30(4):27-30


The SARS-CoV-2 virus emerged as a novel communicable pathogen in late 2019. By May 2023, it had caused more than 100 million COVID-19 cases and more than 1.1 million deaths in the United States and nearly 7 million deaths worldwide.1 In 2020 and 2021, multiple candidate vaccines were rapidly developed and approved, including inactivated virus vaccines, messenger RNA (mRNA) vaccines (Pfizer and Moderna), adenovirus vector vaccines (Johnson & Johnson) and adjuvanted protein vaccines (Novavax). Computer modeling of disease transmission has estimated that vaccination against COVID-19 prevented nearly 120 million cases and more than 3 million deaths in the United States from December 2020 through November 2022.2

In the United States, mRNA vaccines are the most commonly administered, while relatively few doses of adenovirus vector or protein vaccines have been given.3 Updated bivalent formulations of mRNA vaccines targeting the currently circulating SARS-CoV-2 variant became available for booster doses in fall 2022.4 The original monovalent mRNA vaccines were phased out.


As the pandemic progressed and the SARS-CoV-2 virus mutated, additional mRNA sequences targeting variant spike proteins were added to the previously authorized, effective vaccine. These new bivalent mRNA vaccines should now be used for all doses in all age groups, including primary series and booster doses.5 Monovalent (original formulation) mRNA COVID-19 vaccines are no longer authorized by the U.S. Food and Drug Administration and should be discarded.7

The adenovirus vector vaccine is no longer available in the United States following the expiration of all remaining U.S. government stock on May 7, 2023.8

General Recommendations

  • Children ages 6 months and older and adults should stay up to date with COVID-19 vaccination, including at least one dose of a bivalent mRNA vaccine.5

  • For people ages 6 years and older who are not immuno-compromised, a single bivalent mRNA dose is enough to consider them up to date, regardless of previous vaccination status.6

    – Adults ages 65 and older who are not immunocompromised may receive an additional booster dose at least 4 months after their first dose of bivalent mRNA vaccine.5

  • There is no authorized vaccine for infants younger than 6 months. Pregnant and lactating people are strongly encouraged to get vaccinated to provide protection to infants too young to vaccinate.

  • People who are moderately or severely immunocompromised are at higher risk for severe COVID-19 infection than the general population. They may need additional doses in their primary vaccine series, as well as additional booster doses.5

  • Bivalent mRNA vaccines are preferred unless contraindicated.9 The monovalent protein vaccine can be used in certain limited situations.

People Who Are Not Immunocompromised5


Vaccination for COVID-19 in adolescents and adults who are not immunocompromised is now simplified.

  • For people ages 12 years and older who are unvaccinated, a single bivalent mRNA dose is recommended and will bring them up to date.

  • For people ages 12 years and older who have had at least one dose of a monovalent mRNA vaccine or non-mRNA vaccine in the past, a single bivalent booster dose at least 8 weeks after the last monovalent dose is recommended.

Most adolescents and adults who have already received a bivalent dose are not eligible for another shot. However, adults ages 65 and older may receive one additional bivalent mRNA booster dose at least 4 months after their first bivalent vaccine dose.


Primary dosing schedules for children ages 6 months through 5 years are more complex because mRNA products come in different dose strengths and the required number of doses differs based on age. All children should receive at least one dose of bivalent vaccine, but the number of doses needed varies depending on what vaccine the child has previously received. It is ideal for infants and young children to receive all doses in their primary vaccine series from the same manufacturer.

The primary dosing schedule for children ages 6 through 11 years more closely aligns with the schedule for adolescents and adults. A single bivalent primary dose or one bivalent booster dose at least 8 weeks after the last monovalent dose is recommended and will bring them up to date. Partially vaccinated patients ages 6 years and older may receive either brand of bivalent mRNA vaccine.

Recommended COVID-19 vaccination schedules are available on the Centers for Disease Control and Prevention website

People Who Are Moderately or Severely Immunocompromised5

To ensure adequate immune response, children and adults who are moderately or severely immunocompromised continue to need additional vaccine doses. Family physicians may care for patients who have immunocompromising conditions and treatments including active treatment for solid tumor cancers, current or past treatment for hematologic malignancies (e.g., leukemia, lymphoma), receipt of a solid-organ transplant and subsequent immunosuppressive therapy, primary immunodeficiency or HIV infection with CD4 cell counts less than 200/mm3. Common immunocompromising medications include high-dose corticosteroids (i.e., 20 mg or greater of prednisone or equivalent daily for at least 2 weeks) and immunomodulatory biologic agents (e.g., tumor necrosis factor [TNF] blockers). Patients who are moderately or severely immunocompromised can self-attest and be vaccinated against COVID-19 without needing to provide documentation.

Pregnant and Lactating People

Growing evidence supports vaccination during pregnancy to improve maternal, fetal and neonatal outcomes. Compared to non-pregnant people of a similar age, people who are pregnant or within 6 weeks postpartum have increased risk for severe COVID-19 infection, including hospitalization, admission to an intensive care unit, need for mechanical ventilation and death.10,11 Studies have shown that pregnant people who are vaccinated have a lower risk of stillbirth, neonatal intensive care unit admission and preterm birth than those who are not vaccinated.12,13 Further, there is no evidence of adverse effects of vaccination unique to pregnancy, including no evidence of teratogenicity or poor perinatal outcomes.13,14

Pregnant and lactating people are strongly recommended to receive COVID-19 vaccination and remain up to date, with no restrictions regarding timing of doses before, during or after pregnancy.5,15 Professional medical organizations, including the American College of Obstetricians and Gynecologists, the American Academy of Family Physicians, the American Academy of Pediatrics and the Society for Maternal-Fetal Medicine, continue to advocate for COVID-19 vaccination in this vulnerable group.16


There are only a few contraindications to COVID-19 vaccination, including the following5,17:

  • People who have had a severe allergic reaction to a previous dose of COVID-19 vaccine should not receive another dose of the same vaccine type.

  • People who are allergic to polyethylene glycol (PEG) should not receive an mRNA vaccine, but they may get a protein vaccine.

  • People who are allergic to polysorbate should not get a protein vaccine, but mRNA vaccines are safe for them.

In addition, adults who cannot or will not receive an mRNA vaccine may get a protein vaccine. Some monovalent COVID-19 vaccine products are expired or expiring soon, so it is important to check the vaccine's expiration date prior to administration.18

None of the vaccines used in the United States include any preservatives, antibiotics, animal tissue (e.g., gelatin, cells) or food proteins (e.g., egg, gluten).17 Offering 30 minutes of monitoring to patients with a history of allergic reaction to injectable medications of any kind is recommended as a precaution.5

Best Practices for Family Physicians

1. Standardize Your Messaging About COVID-19 Vaccines

As the world transitions into management and mitigation of endemic COVID-19, maintaining population immunity to the virus is still the most important strategy to reduce its impact. Family physicians are a trusted source of information and advice to protect patients, families and communities from the virus.

  • Consider naming a vaccine champion for your practice to educate and encourage staff.

  • Continue to strongly recommend and provide COVID-19 vaccines for as many eligible patients as possible in your practice. Visible high-volume COVID-19 vaccination sites have closed, so family physicians have an indispensable role in vaccinating their patients against the virus.

  • If your practice does not offer COVID-19 vaccination for any reason, point your patients to or recommend another resource to help them find COVID-19 vaccines in your area.

2. Practice Opportunistic Vaccination

It is important to take time to review your patients' risk factors and immunization history and strongly recommend getting vaccinated if they are not up to date. Most people in the United States are not up to date with COVID-19 vaccination. For example, only 17% of the total population and only 43% of adults ages 65 and older had received a bivalent booster dose as of May 2023.3

COVID-19 vaccines can be coadministered with influenza, tetanus-diphtheria-pertussis and pneumococcal vaccines. They have been added to the 2023 routine childhood immunization schedule, ensuring coverage in the Vaccines for Children (VFC) program.19,20 COVID-19 vaccines are also covered by Medicare Part B and private insurers, and they remain no- or low-cost for patients following the expiration of the federal public health emergency on May 11, 2023.21

3. Plan Ahead for Fall

SARS-CoV-2 will be with us for the foreseeable future and so will the need for COVID-19 vaccines. Hopefully, summer months will offer a reprieve from the challenging surges of infections seen in the past few years. Summer also brings the planning and forecasting meetings of vaccine regulatory and advisory panels that determine the strain composition of vaccines. Similar to their annual process for the influenza vaccine, manufacturers may update COVID-19 vaccine formulations for the fall.

You can reassure your patients that there is continued safety monitoring for COVID-19 vaccines. This is also a good time to prepare for coadministration of COVID-19 vaccines with flu shots during the upcoming influenza season.

The AAFP's Immunizations and Vaccines webpage provides information and resources to support your efforts to get your patients up to date on vaccinations.

This publication is funded under the AAFP's "Improving Adult Immunization Rates Among Racial and Ethnic Minority Populations" project, which is supported by a Cooperative Agreement from the Centers for Disease Control and Prevention (6 NU66IP000681-02-01). (The author is solely responsible for the content and does not necessarily represent the official views of the CDC.)

© 2023 American Academy of Family Physicians. All rights reserved.

Continue Reading

More in FPM

Copyright © 2023 by the American Academy of Family Physicians.

This content is owned by the AAFP. A person viewing it online may make one printout of the material and may use that printout only for his or her personal, non-commercial reference. This material may not otherwise be downloaded, copied, printed, stored, transmitted or reproduced in any medium, whether now known or later invented, except as authorized in writing by the AAFP.  See permissions for copyright questions and/or permission requests.