Impact of WASH factors on trachoma prevalence
Reviewed by Nishita Patel

Trachoma is the leading infectious cause of blindness globally. Following a national population-based trachoma survey in Malawi, one round of azithromycin mass drug elimination (MDA) was carried out successfully – that is, the prevalence of trachomatous inflammation, follicular (TF) in a post-MDA impact survey fell below 5%. Nevertheless, TF was still present in 209 (1.3%) of 16,142 children following MDA. The aim of this study was to determine whether water, sanitation and hygiene (WASH) factors play a role in ongoing ocular C trachomatis infection in children following successful azithromycin MDA. A secondary analysis was performed on the post-MDA impact survey data for children aged between one and nine years. Logistic regression analysis, adjusted for clustering at the household and village, was completed. Factors associated with a significantly lower odds of TF after MDA were living in a household with a handwashing facility with water and / or soap [adjusted odds ratio (aOR):0.37] and living in a household where water for washing is located further away from the home (30 mins away aOR:0.39, p=0.034, or more than one hour away (aOR:0.31, p=0.018) compared with water in the yard. The inverse association between a domestic handwashing facility and TF is consistent with previous findings, however the association between increasing distance to collect water for washing and a reduced risk of TF was unexpected and may reflect the impact of drought and unmeasured behavioural factors related to water usage. Limitations to this study have been acknowledged and include the need for additional questions on sociodemographic characteristics of households and behavioural aspects of WASH factor access which are recognised risk factors for trachoma. Further work is also required to validate these findings, given the dataset used was cross-sectional, to provide a better insight into the role of WASH factors in maintaining low levels of trachoma.

Water, sanitation, and hygiene (WASH) factors influencing the effectiveness of mass drug administration to eliminate trachoma as a public health problem in Malawi.
Dyer CEF, Kalua K, Chisambi AB, et al.
OPHTHALMIC EPIDEMIOLOGY
2024;31:127–33.