A breakthrough was announced Thursday for people living with Type 1 diabetes.New research out of Massachusetts General Hospital finds a common vaccine can reverse advanced cases of the disease.Dr. Denise Faustman led the eight-year study testing whether a vaccine for tuberculosis could lower blood sugar levels permanently."This trial is unique in treating people who have longstanding disease -- 10, 15, 20 years out," she said.The researchers found that three years after receiving two doses of the drug, blood sugar levels dropped into the near normal range and stayed there."If they get vaccinated twice, there's a delay. But then, after about 3.5 years, their blood sugars come down, not to the total normal range, but near normal range," Faustman said. Being in that normal range dramatically reduces the risk of complications, things like cardiac disease, blindness, renal disease.Faustman and her team believes their research shows the BCG vaccine helps the body produce a hormone called TNF. It's a hormone people with Type I diabetes need. The next step is to replicate these findings with another trial that is now underway.Faustman also said researchers believe the drug could play a role in Type 2 diabetes treatment, although those studies are not yet set up.