A simple water treatment solution dramatically slashed child mortality in rural Kenyan villages

A new paper by some of the top economists in the world has found that a simple water treatment solution could dramatically reduce child mortality in low-income countries. Spearheaded by Johannes Haushofer, recent Nobel winner Michael Kremer, Ricardo Maertens, and Brandon Joel Tan, these promising findings are reportedly the result of a large-scale experiment called WASH Benefits, which randomly selected certain villages in rural Kenya to receive a variety of water, sanitation, and hygiene (WASH) programs while keeping some other villages as a control group. Among the array of WASH interventions tested — including more sanitary latrines, programs promoting hand-washing with soap, and nutrition supplements for young children — a relatively simple tactic jumped out with astonishing results: adding a simple chlorine solution to drinking water.

According to Vox, the study looked at data from Evidence Action — an aid group launched in 2013 — which installed uniquely-engineered chlorine dispensers next to commonly-used water sources in Uganda, Kenya, and Malawi as part of its Dispensers for Safe Water program. The dispensers enabled people to treat their water using a safe and pre-measured dose of chlorine which stays active for 2-3 days, ensuring water doesn't get recontaminated even when stored at home. 

Using data collected from the target villages in 2018 on the deaths of all children born after January 2008, the study compared death rates in villages that got these chlorine dispensers four to six years earlier to those in villages that didn't get them. According to the paper titled Water Treatment and Child Mortality: Evidence from Kenya, four years of community-wide provision of dilute chlorine solution resulted in an astonishing 63 percent drop in the mortality rate for children under five. While the baseline death rate for children under five in the control villages was a staggering 2.23 percent — ie. over one in 50 children died before their fifth birthday — chlorine usage cut that rate to 0.82 percent, or less than one in 100.

To be clear, 0.82 percent is still far too high. In comparison, the under-5 death rate in the US in 2019 was about 0.13 percent. However, cutting child mortality by more than half is undeniably a huge achievement. The WASH interventions in the study were specifically targeted to pregnant women, which could help explain why they saw such large effects on small children. Changes in water quality starting in the womb have been found to ripple out over the first few years of a child's life, reducing rates of diarrhea and other conditions caused by waterborne illnesses that can prove life-threatening.

Going by data from Evidence Action, the researchers estimate that the program saves a life for about $1,941. One of the authors of the new paper, Haushofer, told reporters in an email that he was "very happy about (and mildly shocked by) those results." Waterborne diarrheal diseases like rotovirus, E. coli, or cholera, are the biggest threats that water treatment programs are meant to target in low-income countries. As of 2016, diarrhea was the eighth leading cause of death in the world, killing about 1.6 million people of all ages that year, of which 446,000 were children. Better water quality can also reduce rates of other illnesses. Reducing rates of diarrheal illnesses has also been found to reduce rates of respiratory illness, for instance.