A clinical trial published in the New England Journal of Medicine showed that the oral antibiotic levofloxacin taken once-daily for six months substantially reduced the risk of developing drug-resistant tuberculosis (TB), and almost halved adults' and children's risk of developing multidrug-resistant TB.

The trial enrolled 2,041 family members of people with drug-resistant TB. These family members had early infection, which had not yet developed into the active form of drug-resistant TB. The study was conducted across 10 provinces in Vietnam, a country with a high rate of drug-resistant TB.

The trial found that levofloxacin reduced the risk of multidrug-resistant tuberculosis (MDR-TB) in adults and adolescents by 45 percent.