A Randomized Trial of Text Message-Based Nudges to Increase COVID-19 Vaccination

The COVID-19 pandemic has caused significant morbidity and mortality across the world. Effective vaccines are now available but underutilized. In July 2021, Ascension Health implemented a mandate requiring all employees to obtain the COVID-19 vaccine by November 12th. In August 2021, the number of COVID-19 cases in the US increased rapidly, specifically in states with lower vaccination rates, many of which are served by Ascension Health facilities.

Nudges are subtle changes to the way information is framed or choices are offered that can have a significant impact on behavior. Status quo bias is a preference for the current state which is often used as a reference point when making decisions. Changes from the reference point are often faced with high inertia and this prevents changes in behavior. Default options are the setting of the baseline reference point and are often taken as an implicit recommendation. In prior work, changing default options has led to significant changes in health-related behaviors. For example, changing prescription default settings in the EHR from opt-in to opt-out for generic prescriptions increased the rate of generic prescriptions from 75% to 98% across Penn Medicine (Patel et al. Annals of IM. 2014; Patel et al. JGIM 2018). Framing program participation as opt-out has led to a 22% increase in enrollment in a COVID-19 surveillance testing program (Oakes et al. NEJM Catalyst 2021) and triple enrollment in remote monitoring programs for medication adherence (Mehta et al. JAMA Cardiology. 2018) and diabetes management (Aysola et al. AJHP 2016)