When Baltimore's health commissioner and mayor were seeking state permission in the 1990s for the nation's first big-city needle exchange program for intravenous drug users, the two government officials knew there was powerful political opposition to anything that appeared to aid drug use.
They turned to an epidemiologist from Johns Hopkins' Bloomberg School of Public Health, David Vlahov, whose studies helped make their case.
"With Hopkins came some cachet with policy and lawmakers," said Dr. Peter Beilenson, the former health commissioner. "The research was invaluable in getting the program off the ground and perpetuating it."
It was not the first or the last time public policy was grounded in the behind-the-scenes work of researchers affiliated with the Bloomberg School, the oldest such institution in the country. As the school celebrates its centennial this month, many inside and outside Hopkins point to resulting treatments, preventive measures and programs, and public policies affecting broad sections of the American and global population.
The school was established in 1916 as the Johns Hopkins School of Hygiene and Public Health with a grant from the Rockefeller Foundation. Within a few years it settled into its bread-and-butter work of investigating infectious disease and created the nation's first department of epidemiology — the study of infectious diseases — which investigated the impact of a global flu pandemic that killed at least 20 million people between 1918 and 1920.
The school moved to its current location at East Monument and Wolfe streets in East Baltimore in 1925 and since has been credited with shaping the field of public health by setting research standards and training future professionals. (It was renamed in 2001 for Michael Bloomberg, the former New York City mayor, philanthropist and mega-donor.)
Those who were educated or employed by the school over the past century have had a hand in the eradication of smallpox, the chlorination formula that makes municipal water supplies safe, and the screening process that protects the nation's blood supply. They also were responsible for discovering that vitamin D prevents rickets, that penicillin treats syphilis, that HPV causes cancer and that smoking reduces life expectancy. A former faculty member helped establish an agency in 1951 that has become the U.S. Centers for Disease Control and Prevention.
Last week, a Bloomberg School study on gun violence was used by a national newspaper in an editorial to make the case for renewal of the federal ban on assault weapons after the mass shooting in Orlando, Fla. It had to rely on the school's research because the CDC no longer conducts firearms research. The study found that a 20 percent drop in incidents involving large-capacity magazines would translate into about 100 fewer homicides and 500 fewer gunshot wounds a year.
"We have to and do take on anything," said Dr. Michael J. Klag, who joined the Hopkins faculty in 1987 and became the Bloomberg School dean in 2005. "We take a problem on as long as we can measure the population health outcome."
Raimee Eck, president-elect of the Maryland Public Health Association, an organization of public health professionals and a student at the Bloomberg School, noted that in the past century the average life span of a person living in the United States has increased more than 25 years because of the contributions of public health advances.
Vlahov, the needle exchange researcher who is now the dean of the School of Nursing at the University of California, San Francisco, said his data "responded to skeptics" by showing clean needles would slow the spread of infectious diseases such as HIV and wouldn't increase drug use or encourage kids to try drugs.
Baltimore's Health Department more recently has relied on the school's research to determine how to tackle the city's so-called food deserts, communities that lack places to buy fresh food, and to assess the cost-effectiveness of the department's violence intervention program, known as Safe Streets.
"Lots of things seem like common sense," said Dr. Leana Wen, the city's current health commissioner. But, she added, "it's necessary to have data, clear metrics and objective evaluation."
Sometimes the research is necessary to gain or keep funding for programs, she said.
But the studies can be controversial when they are used to bolster a change in public policy or public opinion. For example, Dr. Leon Gordis, an epidemiology professor, drew fire from many in the health care industry when a National Institutes of Health panel he chaired suggested that women in their 40s shouldn't necessarily have routine mammograms and should instead weigh the test's risks and benefits. That was in 1997, but the debate continues today on when women should be scanned.
Perhaps the biggest modern controversy — and the one that sowed the most distrust in some Baltimore neighborhoods — centered on studies by a school-affiliated researcher into ways to mitigate exposure to lead paint, a particular scourge in poor black communities. The studies, mostly conducted decades ago, were criticized for what study participants have said were failures to notify study participants of potential harms.
Dr. Marvin L. "Doc" Cheatham Sr., a former Baltimore NAACP president, said the Bloomberg School, and Johns Hopkins generally, still has a way to go in rebuilding community trust.
"One would have to say that the Bloomberg School of Public Health has done a number of significant things here in the Baltimore area, and we have to tip our hats to them," he said. "However, when one looks at the questionable practices during the years, it's not done enough to outweigh the injustices."
Klag, the school dean, said the research has contributed to a reduction in lead toxicity among Baltimore's children by more than 90 percent, but acknowledged Hopkins as a whole had to make changes in its approach.
He said that through institutional and volunteer efforts, community members now find employment or health care at Hopkins, and the university continues to look for ways to serve as a "community anchor." At the Bloomberg School, research now involves more upfront conversation, and a nod to local culture, be it in East Baltimore or an African village.
"Obviously, we feel that we must build trust for the kind of work we want to do," Klag said. "The communities have to be part of it. ... Perhaps we can always do a better job of working with community and collaborating."
Klag said the school will continue to broaden its research. The historical focus on infectious diseases such as HIV and malaria now shares attention with noncommunicable diseases and social determinates of health such as how much people smoke and how much soda they drink. Research already shows that raising taxes on cigarettes and banning smoking in public places vastly reduces consumption, which could in turn reduce chronic health problems and early deaths.
One thing isn't likely to change despite the school's expanded reach. The nitty-gritty work, like Vlahov's needle studies, will mostly remain behind the scenes, Klag said.
"The interventions impact whole populations," he said. "Sometimes people don't even know they are being touched by an intervention."
Baltimore Sun librarian Paul McCardell contributed to this article.