January 14, 2013

Less reaction to DTaP vaccine given in kids’ thighs than arms

Vaccine Safety Datalink study of 1.4 million children at Group Health, etc., in Pediatrics

Seattle, WA—Children age 12 to 35 months who receive DTaP vaccine in their thigh muscle rather than their arm are around half as likely to be brought in for medical attention for an injection-site reaction. So says a new study of 1.4 million children at Group Health and seven other Vaccine Safety Datalink (VSD) centers across the country, e-published on January 14 in Pediatrics.

“These local reactions are the most common side effect of vaccinations,” said study leader Lisa A. Jackson, MD, MPH,a senior investigator at Group Health Research Institute. “But we have known relatively little about how to prevent them.” Local reactions go away after a day or two, but they can be painful, and the associated redness and swelling can concern parents. This study focused on “medically attended” local reactions: ones that resulted in a visit to a doctor, nurse, or emergency room. Ideally, medically attended local reactions would happen less often than the current nearly one in 100 vaccinated children.

“Our findings support current recommendations to give intramuscular vaccinations in the thigh for children younger than 3 years,” Dr. Jackson said. Since 2011, the U.S. Advisory Committee on Immunization Practices (ACIP) has recommended that intramuscular vaccinations be given to toddlers aged 12 to 35 months preferably in the thigh muscle (or in the deltoid muscle of the arm only if it’s big enough)—and to children age 3 years older in the deltoid muscle of the arm. But in practice, health care providers tend to vary in their choice of vaccine injection sites for children; and parents can influence that decision.

The research team also tracked local reactions in children age 3 to 6 years and from intramuscular vaccines other than DTaP, including inactivated influenza and hepatitis A. But they found no statistically significant differences between vaccinating in the thigh and arm in the older age group or for the other intramuscular vaccines.

Previous evaluations of local reactions after the fifth DTaP vaccine in children age 4 to 6 years found that vaccination in the thigh was linked to a lower risk of local reactions than was vaccination in the arm. Dr. Jackson also led an earlier study that showed that neither ibuprofen (Advil) nor acetaminophen (Tylenol) help prevent local reactions after that vaccine.

The current research followed children age 1 to 6 years who received intramuscular vaccines from 2002 to 2009 at the eight VSD sites: Group Health; Harvard Pilgrim Health Care in Boston; HealthPartners in Minneapolis; Marshfield Clinic in Wisconsin; Kaiser Permanente Colorado in Denver; Kaiser Permanente Northwest in Portland; Kaiser Permanente Northern California in Oakland; and Kaiser Permanente Southern California in Los Angeles. The VSD project is a collaborative effort between the Centers for Disease Control and Prevention (CDC)'s Immunization Safety Office and 10 managed care organizations, including these eight (whose research institutes also happen to be members of the HMO Research Network).

Dr. Jackson had five coauthors at Group Health Research Institute: Biostatistician Do Peterson, MS; Associate Investigator Jennifer C. Nelson, PhD; and Programmer Analysts Tracey Marsh, MS, and Lawrence Madziwa, MAS. Dr. Jackson also holds appointments at the University of Washington Schools of Public Health and Medicine. Her other coauthors were S. Michael Marcy, MD, of Kaiser Permanente Southern California’s Department of Research & Evaluation, in Pasadena; Allison L. Naleway, PhD, of Kaiser Permanente Northwest’s Center for Health Research, in Portland, OR; James D. Nordin, MD, MPH, of HealthPartners Institute for Education and Research, in Minneapolis; James G. Donahue, DVM, PhD, of Marshfield Clinic Research Foundation, in Marshfield, WI; Simon J. Hambidge, MD, PhD, of Kaiser Permanente Colorado’s Institute for Health Research and Denver Health Community Health Services, in Denver; Carolyn Balsbaugh, MPH, of the Department of Population Medicine, Harvard Pilgrim Health Care Institute and Harvard Medical School, in Boston; Roger Baxter, MD, of the Kaiser Permanente Vaccine Study Center at the Division of Research in Oakland, CA; and Eric Weintraub, MPH, the CDC’s Immunization Safety Office, in Atlanta.

This study was supported by the CDC (contract 200-2002-00732), through America’s Health Insurance Plans.


Pediatrics is an official peer-reviewed journal of the American Academy of Pediatrics. Continuously published since 1948, it publishes original research, clinical observations, and special feature articles in pediatrics, as broadly defined.

Vaccine Safety Datalink

The Vaccine Safety Datalink (VSD) project is a collaborative effort between the Centers for Disease Control and Prevention (CDC)'s Immunization Safety Office and 10 managed care organizations. The VSD project was established in 1990 to monitor immunization safety and address the gaps in scientific knowledge about rare and serious events following immunization.

Harvard Pilgrim Health Care Institute’s Department of Population Medicine

The Harvard Pilgrim Health Care Institute’s Department of Population Medicine is a unique collaboration between Harvard Pilgrim Health Care and Harvard Medical School. Created in 1993, it’s the only appointing medical school department in the United States based in a health plan. Its staff includes leading physicians, researchers, clinicians and public health professionals, and their research and teaching help address many pressing.

HealthPartners Institute for Education and Research

HealthPartners Institute for Education and Research is dedicated to improving the health of our members, our patients, and the community. Our vision is to deliver outstanding health, experience, and affordability outcomes for the people we serve through discovery and continuous learning. The Institute is part of a larger organization consisting of HealthPartners, Regions Hospital, and clinics.

Marshfield Clinic Research Foundation

The mission of the Marshfield Clinic Research Foundation is to discover and communicate scientific knowledge that substantially improves human health and well-being. The Research Foundation mission supports the Marshfield Clinic mission to serve patients through accessible, high quality health care, research and education.

About Kaiser Permanente

Kaiser Permanente is committed to helping shape the future of health care. We are recognized as one of America’s leading health care providers and not-for-profit health plans. Founded in 1945, Kaiser Permanente has a mission to provide high-quality, affordable health care services and to improve the health of our members and the communities we serve. We currently serve more than 12.4 million members in eight states and the District of Columbia. Care for members and patients is focused on their total health and guided by their personal Permanente Medical Group physicians, specialists and team of caregivers. Our expert and caring medical teams are empowered and supported by industry-leading technology advances and tools for health promotion, disease prevention, state-of-the-art care delivery and world-class chronic disease management. Kaiser Permanente is dedicated to care innovations, clinical research, health education and the support of community health. For more information, go to: kp.org/share.

Jennifer C. Nelson, PhD

Director, Biostatistics; Senior Investigator
Kaiser Permanente Washington Health Research Institute

Media contact

For more on Kaiser Permanente Washington Health Research Institute news, please contact:

Amelia Apfel


(425) 507-5455
After-hours media line: (206) 287-2055

page-twitter-icon.png @KPWaResearch