MIP vaccine could reduce new leprosy cases in India by 60%

The Indian government has announced that it is stepping up its efforts to eradicate leprosy by testing a vaccine that if successful could cut the number of new reported cases by 60 per cent in three years in the targeted districts.

The vaccine, which was recently approved by the Drug Controller General of India, will be rolled out in a project involving five districts in the states of Bihar and Gujarat, where there are high rates of leprosy.

People affected by leprosy as well as their families and other people who come into close contact with them on a regular basis, such as colleagues, will benefit from the project, making India the first country in the world to have a large-scale leprosy vaccination initiative.

They will be given the vaccine, mycobacterium indicus pranii (MIP), in combination with a single dose of the drug rifampicin, which is already being trialled in several countries to prevent leprosy in those who have been exposed to family members who already have the disease. A recent study by The Leprosy Mission in Bangladesh found that new leprosy cases among people who had been given a single dose of rifampicin were almost 60 per cent fewer than among those who had been given a placebo.

News about the vaccine came shortly before the World Health Organisation (WHO) published new figures that show that reported new cases of leprosy in India made up 60 per cent of reported cases worldwide in 2015 - 127,326 out of 210,758.

Experts believe that these figures represent just a fraction of the true picture of people affected by leprosy. Lack of awareness, insufficient access to medical treatment and severe stigma surrounding leprosy mean that millions more could be living with the effects of the disease, going untreated.

Despite these figures, the country was declared to have eliminated leprosy in 2005, meaning that less than one in 10,000 people there is reported to be affected by the disease. This led to the fight against leprosy being neglected for some years, something that the country is now looking to change - with a government target of eradicating the disease by 2020. This will be aided by what Dr Soumya Swaminathan, director general of the Indian Council of Medical Research, has called a “multi-pronged attack” on the disease.

The vaccination project is being combined with a more active approach to the detection of new cases. Door-to-door screenings in 50 leprosy ‘hotspots’ have already seen 5,000 people newly diagnosed.

Testing of the MIP vaccine that took place in 2005 showed that the vaccine was effective for seven to eight years, after which a booster dose would need to be given. If the new project proves to be successful, it is hoped that the vaccine will be used across the country for mass immunisation of contacts of those affected by leprosy, but some leprosy experts have urged caution, stating that from what is known about it so far, it is unlikely that it could eradicate leprosy.

“If the vaccine is a success, we may succeed in immunising all who are vulnerable to leprosy; but there are other issues we should address before we think of eradication,” said Dr Uptal Sen Gupta, consultant at The Leprosy Mission Trust India’s Stanley Browne Laboratory in Delhi. “Unless we improve the living conditions, health and hygiene of our people, we cannot eradicate leprosy.”

Dr Paul Saunderson, Medical Director at American Leprosy Missions, another organisation funding vaccine research, said, referencing the claim that the vaccine could cut new cases by up to 60 per cent: “MIP is an affordable and practical vaccine for leprosy, but relatively weak in terms of protective effect.”

He added that the vaccine has the potential to be combined with other treatment to be more effective – for example the single dose of rifampicin that will be given as part of the Indian project – but that at this point, it is unknown what the outcome of this will be.

Dr Sunil Anand, Director of The Leprosy Mission Trust India (TLMTI), said that TLMTI will “wait and watch for progress” on the project and that the organisation is particularly interested how the study will deal with the ethical issue of providing rifampicin to “close contacts” such as colleagues, if the person affected by leprosy does not want that fact to be known due to fear of stigma.

Perhaps one of the greatest barriers to ending leprosy is the stigma that persists in India, with numerous laws discriminating against people affected by the disease. This discourages others from seeking treatment because they fear being ostracised once people know they have leprosy.

At present, one thing is clear – the war against leprosy must be fought on many fronts if this notoriously complex disease is to be eradicated. This vaccine is just one tool of many needed to end this ancient disease.