Covid19
Conditions
Keywords
COVID19 vaccination, Behavioral science interventions, Vaccination promotion
Brief summary
To reach herd immunity for COVID-19, experts estimate that 70% of the population will need to be vaccinated. However, vaccination rates have begun to slow down in the United States. The investigators will partner with Philadelphia to launch a COVID-19 vaccination sweepstakes, in which residents will be eligible to win if they have received at least one dose of the COVID-19 vaccine prior to a given drawing. Drawings will be held every two weeks; multiple prizes of various sizes will be awarded in each drawing. Half of the prizes in each size category in each drawing will be awarded to residents of a zip code that is randomly selected from a pre-defined list of under-vaccinated zip codes (this zip code will be announced at the start of each 2-week drawing period), the other half will be awarded to residents outside of that selected zip code. The investigators will analyze vaccination rates in Philadelphia as compared with neighboring regions before, during, and after the specified time period, as well as analyze vaccination rates in the three selected zip codes compared to the other zip codes that could have been targeted (the residual set of under-vaccinated zip codes) to determine the effectiveness of the sweepstakes at encouraging vaccinations.
Interventions
BEHAVIORALPhilly Vax Sweepstakes
The Philly Vax Sweepstakes is a citywide sweepstakes designed to motivate Philadelphians to get vaccinated against COVID-19. A total of 36 vaccinated Philadelphians will win among three cash prize packages, distributed from the total cash pool. These 36 will be chosen over three drawings, with 12 residents chosen in each drawing.
Sponsors
Philadelphia Department of Public Health
University of Pennsylvania
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
HEALTH_SERVICES_RESEARCH
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* All 18+ residents of the City of Philadelphia will be eligible. Residents will be able to win the sweepstakes prizes if they can verify they received at least one dose of the COVID-19 vaccine before the date of the sweepstakes drawing in question.
Exclusion criteria
* None.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Weekly Vaccinations Per 100k Residents | 15 Weeks | The primary outcome is the weekly vaccinations (per 100k residents) for residents receiving a first dose of a COVID-19 vaccination in each zip/county/city, relative to the control group. The vaccination data was measured by local health departments and the residency data was measured by the U.S. Census. The investigators included data from 5 weeks of pre-intervention, 6 weeks of intervention, and 4 weeks of post-intervention. Weekly Vaccinations per 100k Residents = 100,000 \* Total residents receiving a first dose that week / Total residents in that zip/county/city code as measured by the Census or other official sources, at the most recent date available for all geographies of interest. |
Countries
United States
Participant flow
Recruitment details
For our sweepstakes cash prizes, selected ZIP Codes with a high selection of cash prize winners (12 residents in each drawing) were 19126, 19133, and 19142 during Periods 1, 2, and 3, respectively.
Participants by arm
| Arm | Count |
|---|---|
| Control No Intervention: Control participants (residents of Bucks County, Montgomery County, Delaware County, and Allegheny County, PA) are not eligible for the sweepstakes. | 2,585,846 |
| Selected Zip Code Treatment A total of 36 vaccinated Philadelphians won three cash prize packages, distributed from the total cash pool. These 36 were chosen over three drawings (i.e. treatment periods), with 12 residents chosen in each drawing. Selected Zip Code Treatment participants won half of these prizes and therefore had a significantly greater chance to win a prize in the sweepstakes than all other Philadelphia residents. A total of three zip codes were selected over the course of the Philly Vax Sweepstakes, one during each of the three treatment periods (19126 during period 1, 19133 during period 2, 19142 during period 3). | 52,874 |
| All Other Philadelphia Residents Treatment Philadelphia has 46 residential zip codes. During each treatment period one of these zip codes was randomly chosen to be the selected zip code. The other 43 zip codes were therefore in the All Other Philadelphia Residents Treatment. | 1,188,936 |
| Total | 3,827,656 |
Baseline characteristics
| Characteristic | Total | Control | Selected Zip Code Treatment | All Other Philadelphia Residents Treatment | — |
|---|---|---|---|---|---|
| Age, Customized | 0 Participants | — | — | — | — |
| Race and Ethnicity Not Collected | 0 Participants | — | — | — | — |
| Region of Enrollment United States | 3827656 participants | 2585846 participants | 52874 participants | 1188936 participants | — |
| Sex/Gender, Customized | — | — | — | — | — participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk | EG002 affected / at risk |
|---|---|---|---|
| deaths Total, all-cause mortality | 0 / 2,585,846 | 0 / 52,874 | 0 / 1,188,936 |
| other Total, other adverse events | 0 / 2,585,846 | 0 / 52,874 | 0 / 1,188,936 |
| serious Total, serious adverse events | 0 / 2,585,846 | 0 / 52,874 | 0 / 1,188,936 |
Outcome results
Primary
Weekly Vaccinations Per 100k Residents
The primary outcome is the weekly vaccinations (per 100k residents) for residents receiving a first dose of a COVID-19 vaccination in each zip/county/city, relative to the control group. The vaccination data was measured by local health departments and the residency data was measured by the U.S. Census. The investigators included data from 5 weeks of pre-intervention, 6 weeks of intervention, and 4 weeks of post-intervention. Weekly Vaccinations per 100k Residents = 100,000 \* Total residents receiving a first dose that week / Total residents in that zip/county/city code as measured by the Census or other official sources, at the most recent date available for all geographies of interest.
Time frame: 15 Weeks
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Control | Weekly Vaccinations Per 100k Residents | 0 Weekly Vaccinations per 100k Residents |
| Selected Zip Code Treatment | Weekly Vaccinations Per 100k Residents | -4 Weekly Vaccinations per 100k Residents |
| All Other Philadelphia Residents Treatment | Weekly Vaccinations Per 100k Residents | 383 Weekly Vaccinations per 100k Residents |