04/20/2012 08:29 am ET

TIME 100: Barbara Van Dahlen, Ron Fouchier And Robert Grant

TIME Magazine announced their 2012 TIME 100 list -- 100 honorees who were the biggest newsmakers and influencers of the year. Among them were three important health professionals that have been instrumental in effecting the kind of medical innovation that continues to keep us healthy.

Barbara Van Dahlen

Van Dahlen, a psychologist, founded the organization Give an Hour, which connects mental health care professionals with military personel who are suffering from post-traumatic stress disorder.

"Barbara has tenaciously attacked the epidemic of posttraumatic stress disorder, helping break through the stigma that prevents many from seeking help," wrote Admiral Mike Mullen in his short profile.

Ron Fouchier

A preeminent virologist, Fouchier is the man we want during a pandemic. His work on strategies to contain the H5N1 bird flu virus may lead to new ways we can prevent the spread of highly infectious disease.

"Fouchier’s work was designed to help scientists better understand how H5N1 could mutate and how to try to control it if it does," wrote Park.

Robert Grant

Grant is an HIV/AIDS researcher, based at University of California, San Francisco. His work has spanned more than a decade and focuses on infection prevention.

"Treating HIV is one thing, but preventing infections to begin with is the ultimate goal," wrote TIME's Alice Park. "Robert Grant brought us one step closer to that target by championing the idea that two powerful life-saving antiretroviral (ARV) drugs, tenofovir and emtricitabine, which are currently used to treat HIV after a person becomes infected, could also protect healthy individuals from ever acquiring the virus, as long as they took the medications before they engaged in high-risk behaviors."

The TIME 100 list has been published annually since 2004 and includes, each year, a selection of "Scientists & Thinkers."