Working in collaboration with the Carter Center and the Ministry of Health in Ethiopia, NEI-funded researcher, Thomas Lietman, and his research group from the University of California, San Francisco, led a clinical trial in 2007 involving 24 communities in Amhara, Ethiopia, to determine whether treating only children, the core group for trachoma transmission, is sufficient to protect the entire community. The researchers provided mass treatments to children under 11 years of age. After one year, the prevalence of infection among those treated children had decreased dramatically from 48% to less than 4%. Importantly, even the prevalence of infection of older untreated children (and adults) also dropped significantly. Thus, young children appear to transmit the disease to older individuals, so that repeated treatments of children alone might be a sufficient and cost-effective strategy to control the infection throughout the community as expected if the herd effect is similar to that seen with vaccinations (House et al., 2009).

Lietman and his team will closely monitor for development of antibiotic resistant diseases in the communities treated with azithromycin. “It’s a complicated question,” he said. “We think we will select for antibiotic resistance. However, many of us believe that might be a price worth paying if there is truly a reduction in childhood mortality.”

Lietman noted two mitigating factors with regard to antibiotic resistance. In communities treated with azithromycin for trachoma, resistance to the antibiotic gradually disappears over the two years after such treatments stop. In addition, he said, azithromycin belongs to a class of antibiotic that is rarely used in sub-Saharan Africa, so even if an infection is resistant to azithromycin, it could still be treatable by one of six other classes of antibiotics.