WIf someone has leprosy, people living in the same household have the greatest chance of contracting the infection. But in a new trial, providing those contacts with a single dose of an antibiotic typically used to treat tuberculosis dramatically reduced that risk, researchers reported Wednesday.
The trial, which took place in China, confirms the idea of giving close contacts an antibiotic to reduce the chance of spreading the disease, experts said. In addition, the study showed that the antibiotic, rifapentine, was an even more effective form of what is known as “post-exposure prophylaxis,” or PEP, than another antibiotic, rifampicin, which is typically distributed among contacts of people with leprosy under current Guidelines from the World Health Organization.
“This is a very welcome confirmation of the usefulness” of post-exposure prophylaxis, says Jan Hendrik Richardus, emeritus professor of infectious diseases and public health at the Erasmus Medical Center in the Netherlands. Richardus was not involved in the new study, which he was published in the New England Journal of Medicine, but worked on past studies of rifampicin (also called rifampicin).
Richardus noted that rifapentine is more expensive than rifampin, which could mean that some poorer countries or resource-constrained public health programs may not be able to switch to their PEP regimens.
Leprosy, also called Hansen’s disease, is a chronic infection caused by Mycobacterium leprae that primarily affects the skin and peripheral nerves, causing discolored patches and growths on the skin and, in some cases, muscle weakness and paralysis. The bacteria spread through prolonged and repeated close contact with someone over months, through droplets from the nose and mouth. The disease is not transmitted by casual contact or touch. As a result, the main concern for subsequent cases lies with the contacts in the household.
Leprosy has been a treatable disease for decades, especially after clinicians began using multidrug therapy in the 1980s. But experts say strategies like PEP are crucial to curbing cases worldwide, with around 200,000 still reported each year, mostly in Southeast Asia. (They also note that prophylactic antibiotics should only be given to select people, given concerns about antibacterial resistance.)
For the new trial, the team of Chinese researchers (who did not respond to interview requests) divided the household contacts of leprosy patients into three arms: a group that received a dose of rifapentine, a group that received a dose of rifampicin, and a control group. group that was not treated. The primary outcome measure was the incidence of leprosy among household contacts over four years.
Overall, of the 207 clusters of people studied – including 7,000 household contacts – there were only 24 new cases of leprosy over the four years. The incidence of new infections in the rifapentine group was 0.09% (only two cases), compared to 0.33% in the rifampicin group (nine cases) and 0.55% in the control group (13 cases). By one statistical measure, this amounted to a 92% lower incidence in the rifapentine group compared to the control group.
“Providing close contact protection is a potential breakthrough in leprosy prevention,” David Scollard, the former director of the National Hansen’s Disease Program in Baton Rouge, wrote in a statement. editorialalso published Wednesday in the New England Journal.
Scollard highlighted two other points from the process. First, it showed that the benefits of rifapentine lasted for four years while past studies have shown that the protective effect of rifampicin lasted only two years. And, Scollard wrote, while other PEP studies have taken place in areas with relatively high leprosy rates, the new trial showed that the approach could work in a country with low leprosy rates like China — with implications for other parts of the world.
“Post-exposure prophylaxis that is effective in regions with low endemic infection levels is globally desirable,” Scollard wrote.