Electronic Nudges for Influenza Vaccination

To the Editor In a recent study,1 electronically delivered nudges directed at patients with chronic diseases significantly improved influenza vaccination uptake, although the magnitude of improvement was limited. This result may have reflected the selection characteristics of the study population, which included patients with chronic diseases who likely had high baseline awareness of the benefits of influenza vaccination. Consequently, high baseline intent may have attenuated the intervention’s effect. The “repeated letter” group achieved the greatest increase, improving by 13.5%, while other messaging frames, such as “cardiovascular benefits” and “respiratory benefits,” yielded gains of approximately 11.0% to 11.9%. These increases were modest relative to the control group, suggesting a ceiling effect in populations with preexisting intent to be vaccinated. Several factors potentially influencing outcomes were not considered in this study.1 The timing of intervention letters may have affected vaccination behavior, as health risk perceptions can vary at different points in the influenza season. Stratified analyses by timing could provide insight into timing-specific effects on vaccine uptake. Additionally, risk perception may differ across disease groups; for example, patients with cardiovascular disease might respond more to risk-focused messages. Evaluating risk perceptions across subgroups could clarify differential behavioral responses.2 Geographic accessibility to vaccination sites may also have influenced uptake. While Denmark’s electronic letter system ensures broad information dissemination, physical proximity to vaccination sites could directly affect patient behavior. Future research could incorporate geographic accessibility as a variable to better understand its role in vaccine decisions. Furthermore, previous experiences with COVID-19 vaccines, such as adverse reactions or vaccination fatigue, may shape attitudes toward influenza vaccination. Including COVID-19 vaccination history as a confounder may have provided greater insight into the pandemic’s long-term impact on vaccination behavior.3 Recent trials have similarly shown that behavioral nudges have limited impact on COVID-19 vaccine uptake in populations with high baseline intent. Mehta et al4 noted that physician recommendations and scarcity framing had limited effect among individuals already inclined to get vaccinated, while Patel et al5 found that “reserved for you” prompts minimally influenced patients to go to primary care appointments. Behavioral nudges grounded in behavioral economics can increase vaccine uptake, yet randomization may inadequately capture intent variation. Stratified analyses across population subgroups may better assess the utility of these nudges. Enhanced randomization designs—via stratification or adjusted allocation—could better boost vaccination rates across diverse populations, thereby advancing public health goals.

https://jamanetwork.com/journals/jama/fullarticle/2830129