Influence
December 8, 2025

Effectiveness of 2023–2024 COVID-19 vaccines in children in the U.S.

Shaun Grannis, M.D., M.S.

Published in Pediatrics. Here is a link to the article.

Regenstrief Institute author: Shaun Grannis, M.D., M.S., Brian Dixon, PhD, MPA, Colin Rogerson, M.D., MPH

The content below has been provided by Dr. Grannis.

Evaluating Updated COVID Vaccines in Children

The main goal of this study was to see if the updated COVID-19 vaccines, the 2023–2024 formula, were helping children stay out of the emergency room. The study focused on everyday kids, specifically infants, toddlers and teenagers aged nine months to 17 years, who were generally healthy, to see if the vaccine protected them from getting sick enough to need urgent medical care.

Stronger Protection for Children

The study showed that the updated vaccine works, giving children significant added protection against COVID-19. For young children (nine months to four years), the vaccine reduced the likelihood of needing emergency or urgent care for COVID-19 by 35 percent. For school-aged children and teens (five to 17 years), it reduced that risk by 44 percent. These findings confirm that getting the shot helps keep kids healthier and out of the hospital.

Extra protection

The solution offered was the updated 2023–2024 COVID-19 vaccine. For most children aged five and older, this was a single dose to boost their immunity. For younger children, less than four years, it involved making sure they were up to date with their shots, which might include the updated dose as part of their initial series. This simple step was the key to gaining the extra protection described in the study.

What should parents and doctors consider?

Doctors and families should know that while the vaccine is effective, protection can fade over time, which is why keeping up with the latest recommended shots is so important. A critical takeaway from the study was that very few children had received the updated shot –only about four percent to six percent of the kids studied. This low number suggests that many families are missing out on an important tool to prevent severe illness, and providers should encourage vaccination to close this gap.

Future research

Public health experts at the CDC are continuing to monitor these vaccines closely to ensure they remain safe and effective for families. This ongoing research helps shape future recommendations, ensuring that parents have the best tools available to protect their children from getting sick.

Authors and their affiliations:

Stephanie A Irving1, Elizabeth A K Rowley2, Sean Chickery2, Kristin Dascomb3, Allison L Naleway1, Nicola P Klein4, Shaun J Grannis5,6, Toan C Ong7, Malini B DeSilva8, Karthik Natarajan9,10, Tamara Sheffield3, Daniel Bride3, Julie Arndorfer3, Padma Koppolu1, Ousseny Zerbo4, John Hansen4, Lawrence Block4, Karen B Jacobson4, Brian E Dixon5,11, Colin Rogerson5,12, Tom Duszynski5,13, Michelle Barron7, David Mayer7, Catia Chavez7, Zachary A Weber2, Sarah E Reese2, Inih Essien8, Melissa S Stockwell10,14, Ashley B Stephens10, Sarah W Ball2

1Kaiser Permanente Center for Health Research, Portland, Oregon.

2Westat, Inc. Rockville, Maryland.

3Division of Infectious Diseases and Clinical Epidemiology, Intermountain Health, Salt Lake City, Utah.

4Vaccine Study Center, Division of Research, Kaiser Permanente Northern California, Oakland, California.

5Regenstrief Institute Center for Biomedical Informatics, Indianapolis, Indiana.

6Department of Family Medicine, School of Medicine, Indiana University, Indianapolis, Indiana.

7University of Colorado, Anschutz Medical Campus, Colorado School of Medicine, Aurora, Colorado.

8HealthPartners Research Institute, Minneapolis, Minnesota.

9Department of Biomedical Informatics, Columbia University Irving Medical Center, New York, New York.

10New York-Presbyterian Hospital, New York, New York.

11Department of Health Policy and Management, Richard M Fairbanks School of Public Health, Indiana University, Indianapolis, Indiana.

12Department of Pediatrics, School of Medicine, Indiana University, Indianapolis, Indiana.

13Department of Epidemiology, Richard M Fairbanks School of Public Health, Indiana University, Indianapolis, Indiana.

14Division of Child and Adolescent Health, Department of Pediatrics, Columbia University, New York, New York.

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