Study: Vaccines Safe and Offer Benefits to Medically Fragile Children

Marshall Summar, MD, Chief of Genetics and Metabolism at Children’s National Medical Center, is senior author and designer of the study in collaboration with the Centers for Disease Control and Prevention and Vanderbilt University School of Medicine.

While the focus of this study is on medically fragile patients with urea cycle disorders – which result in severe, chronic illnesses – the results have broader implications.

“There has been some concern in the public that vaccinations are not safe for patients with chronic medical conditions or that they might unmask previously unsuspected conditions,” said Dr. Summar. “Our study demonstrates vaccination safety in one of the world’s most medically fragile patient groups. The diseases these vaccines prevent are devastating to these patients, so it is reassuring to know that these vaccinations are safe to give to these patients. Further, that these especially fragile patients have no unusual reactions to these vaccinations underscores the medical community’s assertion that childhood vaccinations are safe for the wider population.”

The study examined the vaccine records of 169 children under the age of 18 with urea cycle disorders and their disease course. Urea cycle disorders are rare genetic conditions affecting the body’s clearance of the toxin ammonia. Children with these diseases are frequently hospitalized when ammonia builds up in their bloodstream. This build up can be triggered by common illnesses and stresses like viral and bacterial infections.

Researchers tracked reactions to several standard childhood vaccines, including diphtheriatetanus-acellular pertussis vaccine; hepatitis A vaccine; hepatitis B (HepB) vaccine, alone or with the diphtheriatetanus-acellular pertussis vaccine; Haemophilus influenzae type b; trivalent inactivated influenza vaccine; inactivated poliovirus vaccine; oral polio vaccine; measles-mumps-rubella vaccines; 7-valent pneumococcal conjugate vaccine; live attenuated rotavirus vaccine; and live attenuated varicella vaccine.

They then focused on the crucial 21-day period following vaccination to determine if there was an increase in hospitalizations and elevated ammonia events than at other times. The results of this study showed vaccinations did not increase the risk for elevated ammonia or hospitalizations in urea cycle patients.

The 169 patients whose vaccine records were studied were participants in the National Institutes of Health-sponsored Rare Disease Clinical Research Network study of patients with urea cycle disorders, based at Children’s National, the international leader in research and treatment of urea cycle disorders and other rare inborn errors of metabolism.

In the same issue of Pediatrics, Dr. Summar also co-authored a study from Kaiser Permanente Northern California similarly demonstrating vaccine safety in a broader group of medically fragile patients with inborn errors of metabolism.

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Contact: Children’s Public Relations Department: Paula Darte or Emily Dammeyer or at 202.476.4500.

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