Water, Sanitation, and Hygiene (WASH) Factors Influencing the Effectiveness of Mass Drug Administration to Eliminate Trachoma as a Public Health Problem in Malawi

Purpose: Following a national population-based trachoma survey in Malawi one round of azithromycin mass drug administration (MDA) was carried out, with a post-MDA impact survey showing TF prevalence below 5% and considered eliminated as a public health problem. However, active trachoma was still present in over 200 children. We assessed whether water, sanitation, and hygiene (WASH) factors were associated with ongoing presence of TF in children aged 1–9 years following MDA. Methods: A secondary analysis was performed on a sub-set of the post-MDA impact survey data for children aged 1–9 years. We used a logistic regression analysis, adjusted for clustering at the household and village level. Results: Among 16,142 children aged 1–9 years, 209 (1.3%) had TF after MDA. Factors associated with a significantly lower odds of TF after MDA were living in a household with a handwashing facility (aOR: 0.37) and living in a household where water for washing is located further away from the home (30 min away aOR: 0.39, p =.034, or more than 1 h away aOR: 0.31, p =.018) compared with water in the yard. Conclusion: The inverse association between a domestic handwashing facility and TF is consistent with previous findings, but the association of increasing distance to collect water for washing with a reduced risk of TF was unexpected and may reflect the impact of drought and unmeasured behavioural factors related to water usage. A more comprehensive collection of sociodemographic and WASH factor information in population-based trachoma surveys will provide insight into achieving and maintaining low levels of trachoma.