COVID-19 Booster Incentives

COVID-19 Booster Incentives in a County-Run Health System

Status

Completed

Phases

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT05648773

Enrollment

57893

Registered

2022-12-13

Start date

2022-12-08

Completion date

2022-12-23

Last updated

2023-08-14

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Booster Message, Booster Message + Financial Incentive

Brief summary

The goal of this work is to understand whether small financial incentives and messaging can increase the take-up of COVID-19 boosters among patients empaneled at a county public health system. The motivation for this work is the relatively low take-up of COVID-19 boosters. In California, where our experiment is based, only 59% of the population has been boosted, with only 13% receiving the recommended bivalent booster (State of California, 2022).

Interventions

BEHAVIORALMessaging

Booster reminder message

BEHAVIORALFinancial Incentive

Financial Incentive for getting boosted within 2-weeks of the message

OTHERPlacebo

Treatment as usual; no additional message and no incentive.

Study design

Allocation

RANDOMIZED

Intervention model

PARALLEL

Primary purpose

HEALTH_SERVICES_RESEARCH

Masking

SINGLE (Subject)

Eligibility

Sex/Gender

ALL

Age

18 Years to No maximum

Healthy volunteers

Yes

Inclusion criteria

1. Age: 18 and above 2. At least one COVID-19 vaccination (primary series or monovalent booster) but no vaccination dose within the past 2-months. 3. Active phone number or email

Exclusion criteria

1\. Opt-out of health system messaging

Design outcomes

Primary

Measure	Time frame	Description
Vaccine booster	2 weeks	Received a booster vaccination within 2-weeks of message.

Countries

United States

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026