COVID-19 Vaccinations With a Sweepstakes

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.

No Intervention: Control participants (residents of Bucks County, Montgomery County, Delaware County, and Allegheny County, PA) are not eligible for the sweepstakes.

Selected Zip Code Treatment participants will have a significantly greater chance to win a prize in the sweepstakes than all other Philadelphia residents. Half of all prizes in every drawing will go to Philadelphia residents in the selected zip code.

All other Philadelphia Residents Treatment participants will be eligible for the sweepstakes. Half of all prizes in every drawing will go to Philadelphia residents outside of the selected zip code.

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.

The primary outcome is the weekly vaccination rate for residents receiving a first dose of a COVID-19 vaccination in each zip/county/city as measured by local health departments and, for residency, as measured by the Census or other official sources. The investigators will include data from 5 weeks of pre-intervention, 6 weeks of intervention, and 4 weeks of post-intervention. Weekly Vaccination Rate = 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. This source as of pre-registering is the American Community Survey 2019.

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.