Stronger-SAFE: understanding transmission and optimising interventions for an enhanced SAFE strategy for trachoma elimination

Trachoma is the commonest infectious cause of blindness and it particularly affects poor rural communities. It is caused by repeated infection with the bacterium Chlamydia trachomatis (Ct). The WHO-endorsed SAFE-Strategy aims to control infection through annual, single-dose, azithromycin antibiotic treatments given alongside water, sanitation, hygiene (WASH), and fly-control measures to suppress transmission of Ct. These interventions also help to improve general health and well-being. However, in areas with a very high starting prevalence of trachoma, the current antibiotic treatment schedule is not having the anticipated effect on incidence. As we do not understand how the Ct infection is passed from one person to another, it is difficult to know how to stop the infection spreading.

In this study we will try to determine the main roots of transmission. This will allow us to develop practical, targeted interventions to limit the spread from person to person. We will then investigate whether using a double dose of the azithromycin given two weeks apart, combined with the new measures to limit transmission can better control the infection.