The effect of a soap promotion and hygiene education campaign on handwashing behaviour in rural India: a cluster randomised trial

Objective  To investigate the effectiveness of a hygiene promotion intervention based on germ awareness in increasing handwashing with soap on key occasions (after faecal contact and before eating) in rural Indian households.
Methods  Cluster randomised trial of a hygiene promotion intervention in five intervention and five control villages. Handwashing was assessed through structured observation in a random sample of 30 households per village. Additionally, soap use was monitored in a sub-sample of 10 households per village using electronic motion detectors embedded in soap bars.
Results  The intervention reached 40% of the target population. Germ awareness increased as well as reported handwashing (a possible indicator of perceived social norms). Observed handwashing with soap on key occasions was rare (6%), especially after faecal contact (2%). Observed handwashing with soap on key occasions did not change 4 weeks after the intervention in either the intervention arm (−1%, 95% CI −2%/+0.3%), or the control arm (+0.4%, 95% CI −1%/+2%). Data from motion detectors indicated a significant but small increase in overall soap use in the intervention arm. We cannot confidently identify the nature of this increase except to say that there was no change in a key measure of handwashing after defecation.
Conclusion  The intervention proved scalable and effective in raising hygiene awareness. There was some evidence of an impact on soap use but not on the primary outcome of handwashing at key times. However, the results do not exclude that changes in knowledge and social norms may lay the foundations for behaviour change in the longer term.