A RECENT nationwide study from Copenhagen University Hospital, Denmark has demonstrated that electronic letters informed by behavioural science can significantly increase influenza vaccination rates among young and middle-aged patients with chronic diseases.
Conducted from September 2023–May 2024 the clinical trial tested whether sending behaviourally informed electronic letters could nudge people toward getting vaccinated. Participants were randomly assigned to receive one of six types of behaviourally tailored letters or to receive no letter at all, which served as the usual care group.
Involving nearly 300,000 individuals aged 18–64, comprehensive Danish health registries were utilised to ensure broad coverage and accurate data. With a 2.45:1 randomisation ratio, the study could explore the effectiveness of multiple intervention strategies while maintaining a robust control group. Across various subgroups, vaccination uptake was consistently higher in those who received the electronic letters, highlighting the effectiveness of targeted messaging in a diverse population.
The study found that all six letter-based interventions led to an increase in vaccination rates, with improvements ranging from 11–14 percentage points over the usual care group. Notably, the most effective strategy was a repeated letter sent ten days after the initial one, which achieved a 41.8% vaccination rate compared to 27.9% in the control group. Another effective approach involved letters that emphasised potential cardiovascular benefits, which boosted the vaccination rate to 39.8%.
These findings underscore the importance of innovative, scalable approaches to public health. Despite strong global recommendations, influenza vaccination rates remain suboptimal, particularly among younger and middle-aged adults with chronic conditions who are at higher risk of flu-related complications. The results suggest that simple, behaviourally informed nudges could play a crucial role in addressing this gap, pointing to the potential of electronic, behaviourally informed communications to be a cost-effective and easily scalable strategy to enhance public health efforts.
Katie Wright, EMJ
Reference
Johansen ND et al. electronic nudges to increase influenza vaccination in patients with chronic diseases: a randomized clinical trial. JAMA. 2024;DOI:10.1001/jama.2024.21060.
