**6. Immunoprophylaxis**

Early diagnosis of cases, aggressive treatment and proactive measures to avoid complications and disabilities is the backbone for the success of any comprehensive program. In addition to accurate reporting and control measures, effective preventions will be needed to achieve elimination. Search for an effective vaccine either to be used alone or in combination with a drug has been going for a long time.

Presently BCG (Bacillus Calmette-Guerin) is the only vaccine that has shown some protection against *M. leprae* bacillus. A single dose of BCG gives 50 percent or higher protection against the disease. It is the most widely used vaccine in the world, yet the degree of protection it confers is not yet confirmed. The meta-analysis of many experimental studies concludes that the vaccine gives approximately 26% protection against leprosy. But the protection level decreases with time. To overcome this problem more than one dose of vaccine is advised.

Other variants of vaccination are also suggested.


Another milestone in prevention of leprosy is the discovery of the vaccine candidate, called LepVax. Scientists at Infectious Disease Research Institute (IDRI), along with national and international collaborators including the

**Figure 7.** *Locations of leprosy vaccine testing.*

National Hansen's Disease Program and the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, with financial support from American Leprosy Missions, have developed this leprosy vaccine. Based on the preclinical studies, the LepVax, has progressed to Phase I clinical testing in the United States, the first stage of safety testing in human volunteers. The clinical trial is focused not only on safety but also evaluates the immune response of the individual to the vaccine.


Chemoprophylaxis alone provides two-year protective window while effective immunization will provide a much broader protective window. Thus many studies and research is going on to provide both chemoprophylaxis and immunization for immediate and short-term protection and longer-term protection respectively. This strategy could have better impact and distinct appeal in controlling and preventing leprosy. Such trials could also provide a gateway for the assessment and implementation of new emerging vaccines (**Figure 7**).
