Leprosy Vaccines: Developments for Prevention and Treatment

Over 200,000 new leprosy cases are reported globally every year. A vaccine for leprosy can eliminate the debilitating, biblical, and stigmatised disease in the twenty-first century. Since the 1940s, many clinical studies have consistently shown that the BCG vaccine offers some level of protection but ranging between 18% and 90%. Throughout this time, different versions of BCG and new developments have resulted in new leprosy vaccine candidates and prevention strategies. Examples are the vaccine and drug combinatory therapy that has shown promise in decreasing transmission and the subunit vaccine candidate, LepVax, which has been shown to reduce bacterial count and delay nerve function impairment in animal models and safe in healthy adults in early studies. The WHO officially recommended the BCG vaccine as a leprosy vaccine in 2018, a century later after it was first used as a tuberculosis vaccine in 1921. However, a better leprosy vaccine and prevention strategy is still needed because we do not exactly know how Mycobacterium leprae spreads and causes neurological damage in leprosy patients. The history and latest developments in leprosy vaccines are explored in this chapter.