While finishing her doctoral degree at Washington State University, Hillier studied the bubonic plague and began to specialize in sexually transmitted diseases.[2] This led her to join the HIV movement led by Polly Harrison and formed the Alliance for Microbicide Development.[2] She co-published a study in 1991 titled Reliability of diagnosing bacterial vaginosis is improved by a standardized method of gram stain interpretation[3] and attended the first White House Conference on HIV and AIDS in 1995 but was met with resistance.[1]