COVID-19: Vaccines and Long COVID

Researchers globally are discovering more about COVID-19, Long COVID-19, and booster shots. The three are linked because booster shots can affect the severity of symptoms of COVID-19 and long-term COVID-19.

covid vaccine


COVID-19 vaccines were quickly developed after the virus spread globally. Researchers worldwide searched for answers using mRNA, a known combatant of similar viruses. Moderna and Pfizer-BioNtech were the first to release vaccines that effectively prevented or decreased the risk of COVID-19 and its symptoms. Since then, the U.S. Food and Drug Administration (FDA) has changed these vaccines and others (Novavax, Comirnaty – produced by Pfizer-BioNtech, and Spikevax- produced by Moderna).


Moderna has two vaccines – Moderna adjuvanted vaccine and Spikevax. Pfizer-BioNtech also has two vaccines-Pfizer-BioNtech and Comirnaty. The 2023-2024 versions help prevent or protect all ages against COVID-19 symptoms that are severe and can cause hospitalization or death. However, there are differences in FDA-approved uses.

Moderna/ Pfizer-BioNtech FDA Authorized Use

  • Six months to 11 years, one or more shots of previous or current formulas: 1 dose
  • At least three doses should be given to children aged six months through 11 years with weakened immune systems. The FDA recommends the updated 2023-2024 formula.


  • People aged 12 and older: 1 dose.
  • People 12 years and older with weakened immune systems should have at least three doses.1,2

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Novavax COVID-19, adjuvanted vaccine

  • Five years to 11 years: Not authorized or approved for use.
  • Children ages six months through 11 years with weakened immune systems – not authorized for use
  • Those 12 or older with weakened immune systems should receive 1 or 2 doses, depending on vaccination history.
  • Those 12 and older: 2 doses3

The vaccines and subsequent booster shots are proven to be effective in decreasing the risk of or the symptoms of COVID-19 and its variants.

Where You Receive a Vaccination May Matter

Researchers discovered that where you receive your booster shot(s) matters. The New York Times reported recently that you may want to alternate arms when receiving COVID-19 vaccines as that may produce a better immune response. The results of this study were published in The Journal of Clinical Investigation.

Long COVID After Effects

In a study published in the Journal of the Royal Society of Medicine conducted by the UCL Institute of Health Information, 59% of Long-term COVID patients experienced single organ injury a year post-COVID. Additionally, the researchers found 29% of those who had COVID-19 had multi-organ impairment. The researchers concluded that further research should focus on the connections between symptoms and organ damage.


The research and discoveries surrounding COVID-19 and vaccines continue to grow. As scientists and medical professionals continue to study the virus, its symptoms, and vaccines, the findings will impact prevention and treatment.


  1. Research, C. F. B. E. A. (2023, December 11). Pfizer-BioNTech COVID-19 Vaccine. U.S. Food and Drug Administration.
  2. Research, C. F. B. E. A. (2023a, November 1). Moderna COVID-19 Vaccine. U.S. Food And Drug Administration.
  3. Research, C. F. B. E. A. (2023a, October 17). Novavax COVID-19 Vaccine, Adjuvanted. U.S. Food And Drug Administration.
  4. One Arm or Two? How You Get Vaccinated May Make a Difference. New York Times, Feb. 6, 2024.


Christina Sisti, DPS, MPH, MS, is a bioethicist and health care policy advocate. She works to create awareness and improve healthcare policy for those with long-term health issues.

About the Author - Reeve Staff

This blog was written by the Reeve Foundation for educational purposes. For more information please reach out to

Reeve Staff

The opinions expressed in these blogs are the author's own and do not necessarily reflect the views of the Christopher & Dana Reeve Foundation.

This publication was supported by the Administration for Community Living (ACL), U.S. Department of Health and Human Services (HHS), as part of a financial assistance award totaling $160,000 with 100% funding by ACL/HHS. The contents are those of the author(s) and do not necessarily represent the official views of, nor an endorsement by, ACL/HHS or the U.S. government.