Nudging COVID-19 Vaccine Uptake by Changing the Default: A Randomized Controlled Trial.

Area of Science:

• Public Health
• Behavioral Economics
• Vaccinology

Background:

• Vaccination against SARS-CoV-2 is crucial for pandemic control.
• Vaccine uptake has lagged behind target rates in many populations.
• Understanding barriers to vaccination is essential for improving public health strategies.

Purpose of the Study:

• To investigate if a nudging strategy could enhance coronavirus disease 2019 vaccine uptake.
• To explore the effectiveness of exploiting status quo bias in vaccination campaigns.
• To compare vaccination acceptance between opt-in and opt-out appointment systems.

Main Methods:

• A randomized controlled trial was conducted in northern Italy.
• 2000 adults aged 50-59 years, unvaccinated against COVID-19, were included.
• Participants were assigned to either an opt-in (invitation to schedule) or opt-out (pre-scheduled appointment) group.

Main Results:

• The opt-out group showed a 3.2 percentage point higher vaccination rate.
• This represents a 32% relative increase in vaccination acceptance for the opt-out group.
• Vaccination rates were 13.1% for the opt-out group versus 9.9% for the opt-in group.

Conclusions:

• Nudging strategies, particularly those reducing required action, can increase vaccination rates.
• A significant portion of unvaccinated individuals may be influenced by inaction and can be encouraged through reduced effort.
• Pre-scheduled appointments (opt-out) are more effective than invitations (opt-in) for boosting vaccine uptake.