A vaccine primarily used for treating tuberculosis (TB) may be effective in reducing high blood sugar among people with Type - 1 diabetes, results from a clinical trial has revealed.

Type - 1 diabetes is a chronic condition in which the pancreas produce little or no insulin. The findings showed that, three years after receiving two administrations of the Bacillus Calmette-Guerin (BCG) vaccine four weeks apart, people with longstanding Type-1 diabetes showed an improvement in HbA1c -- Aglycated haemoglobin -- measured to test the overall sugar levels to near normal levels.

"This is clinical validation of the potential to stably lower blood sugars to near normal levels with a safe vaccine, even in patients with longstanding disease," said Denise Faustman, director of the Massachusetts General Hospital Immunobiology Laboratory, US. The study, published in the journal npj Vaccine, also reported that the effects of BCG vaccine on blood sugar control appear to depend on a totally novel metabolic mechanism that increases cellular consumption of glucose.

The team analysed data from 282 human study participants -- 52 with Type-1 diabetes who participated in the BCG clinical trials and 230 who contributed blood samples for mechanistic studies. The results showed that the HbA1c levels of those receiving BCG had dropped by more than 10 per cent in three years after treatment and by more than 18 per cent in four years. The study showed that BCG vaccination induces epigenetic reprogramming at the chromatin architecture level and functional alterations indicative of a permanent change in immunity. Thus, the clinical effects and the proposed mechanism add to the emerging consensus that the BCG vaccine can have a lasting and valuable impact on the immune system, the researchers said.