2021 Harry Hirsch Leiter Award Recipient:
Targeted Mass Azithromycin Distribution for Trachoma: A Community-Randomized Trial (TANA II)
Hamidah Mahmud1,2, Berhan Ayele3, Zerihun Tadesse3, Sintayehu Gebresillasie3, Ayalew Shiferaw3, Mulat Zerihun3,
Jeremy Keenan2,4, Thomas M. Lietman2,4
1UCSF School of Medicine, San Francisco, California; 2Francis I. Proctor Foundation, UCSF, San Francisco, California; 3The Carter Center, Ethiopia, Addis Ababa, Ethiopia; 4Department of Ophthalmology, University of California, San Francisco, California
Purpose: With current trachoma mass azithromycin distribution, the vast majority of treated individuals are not actually infected. Here, we present preliminary results comparing two targeted mass antibiotic treatment strategies: (1) mass treatment of all pre-school aged children, or (2) targeted treatment of households containing a pre-school child with clinically active trachoma.
Methods: As part of a cluster-randomized trial, 48 communities in the Amhara region of Ethiopia who had already received four rounds of mass azithromycin for trachoma were randomized to one of 4 arms for the next 3 years: (1) annual age-targeted azithromycin to all pre-school children (i.e., 6 months to 5 years), (2) annual household-targeted azithromycin to all households containing a pre-school child with clinically active trachoma, (3) annual mass azithromycin, and (4) cessation of treatment. The pre-specified primary outcome was the prevalence of ocular chlamydia infection in 0-9-year-olds by PCR. A secondary outcome was clinical trachoma (TF and/or TI) in children 0-9-year-olds.
Results: 4100 children aged 0-9 years were monitored annually for the prevalence of ocular chlamydia infection (PCR) and clinical trachoma (TF and/or TI). When corrected for baseline, there was no significant difference between the two targeted treatment arms (i.e., age-targeted vs household-targeted) for PCR prevalence at 36 months (P>0.99, Odds Ratio 1.0, 95% CI -0.6 to 0.6), but the prevalence of clinical activity at 36 months was lower in the household-targeted arm (OR 0.7, 95% CI 0.3 to 1.1, P= 0.004). Compared to communities that stopped treatment, the 24 targeted treatment communities had lower ocular chlamydia (OR 0.5, 95% CI 0.1 to 1.0, P= 0.03) and TF (P = 0.04, OR 0.4, 95% CI 0.1 to 0.8). The 24 targeted communities were not significantly different from the communities continuing annual mass azithromycin distribution in terms of ocular chlamydia (OR 1.0, 95% -0.7 to 0.7, P>0.99) or TF (OR 0.7, 95% CI 0.3 to 1.1, P=0.004).
Conclusions: It was difficult to detect a difference between the age-targeted and household-targeted approaches. However, preliminary results suggest that both strategies were superior to stopping annual azithromycin treatment altogether. Targeted treatment was not significantly different to continuing community-wide annual azithromycin treatment for trachoma. Thus, targeted treatment strategies may be more efficient than mass distribution but are likely not as effective.
Support: NIH-NEI U10 EY016214