Evaluating the impact of a national handwashing campaign in Wales using propensity score matching

Hand hygiene promotion is one of the most cost-effective health actions to reduce the transmission of infectious diseases. Welsh Government commissioned Public Health Wales to deliver a public-facing, preventative behaviours communications campaign for Winter 2023–2024 via print and digital platforms. The aim of the campaign was to increase the number of people in Wales practising good handwashing. A nationally representative survey of 942 Welsh adult individuals (aged 16+) assessed level of campaign recall, and current handwashing behaviours. Propensity score matching (PSM) methods were used to examine the relationship between campaign recall and self-reported correct handwashing practices. Overall, 79% (n = 740) of participants reported washing their hands for less than 30 s. Only 11.3% (n = 106) of survey participants reported seeing the campaign. Younger age groups (16–24 and 25–49) and women were significantly more likely to recall the campaign. PSM analysis found some evidence of increased hand washing duration for those who recalled the campaign (handwashing for 20–29 s odds ratio (OR) 2.87 (95% CI: 1.34–6.22); handwashing 30–39 s OR 1.70 (95%CI: 0.45–5.23); handwashing 40 s or more OR 3.83 (95% CI: 1.21–11.18). The campaign showed limited reach, with lower recall than expected. Weak evidence suggests recall may have had a modest positive effect on handwashing behaviour. These findings highlight the campaign’s potential and the need for improved strategies to increase public recall. The study also demonstrates the utility of propensity score matching for evaluating health promotion campaigns at the population level when randomised trials are not feasible.