Faculty in the Eudowood Division of Pediatric Infectious Diseases at Hopkins Children's have been frequently in the news recently, commenting on multiple aspects of this year's H1N1 virus as well as the safety of the vaccine to prevent it. The efforts here at Johns Hopkins and around the globe to protect children from exposure to H1N1, and to partner with parents and community healthcare providers to care for those who contract it,  will become another chapter in the historic and ongoing fight, at Johns Hopkins, against pediatric infectious diseases. Ironically, the very vaccines developed to conquer their microbes, are now the ones under the microscope.

In 1907, preeminent Austrian physician Clemens von Pirquet was chosen to chair the Department of Pediatrics at Johns Hopkins at a time when infectious diseases were the leading cause of death and disabilities in children. With a background in the study of diphtheria and tuberculosis, and renowned for his study of vaccination and antibodies, Pirquet was the man for the job.

Von Pirquet’s legacy included the design of a children’s hospital at Johns Hopkins to combat epidemics. When it opened in 1912, the Harriet Lane Home for Invalid Children had separate wings to isolate children with different infections, an observation ward, and laboratories to discover cures. Well into the 1940s, tuberculosis and meningitis were frequent illnesses of infancy, and wards were filled with children with polio, diphtheria, measles and mumps. But in the 1950s, the tide began to turn with the development of polio vaccines.

Today, the fight continues at the Lane's predecessor, Hopkins Children's. But with record rates of immunizations, the vaccines themselves are now under scrutiny. Concerned that the vaccines may pose greater risks than the diseases against which they protect, some parents are refusing them. So, in addition to developing new vaccines – Hopkins researchers like Professor of Pepdiatric Infectious Diseases Neal Halsey are studying any adverse effects. “We are looking at all the safety issues,”says Halsey, “and generating the scientific data to make policy.”

Halsey is director of the Institute for Vaccine Safety at Johns Hopkins Bloomberg School of Public Health, which coordinated the scientific review of a possible link between childhood diabetes and vaccines and found no evidence to support the hypothesis. When there was public concern in the late 1990s that a preservative that was used in some vaccines could result in excessive exposures of mercury, Halsey led a review for the Academy of Pediatrics that recommended, as a precaution, levels of the preservative thimerosol be reduced or removed from vaccines given to infants. They were. Subsequent studies have not shown consistent evidence of harmful effects.

Recognizing the potential of vaccines to cause allergic reactions, Halsey and Hopkins immunologist Robert Wood coordinated the development of guidelines for patients with suspected hypersensitivity to vaccines (Pediatrics, September 2008). “Our ultimate goal” says Halsey, “is to create the safest vaccines and maintain parents’ confidence in them.”