The effect of a proof-of-vaccination requirement, incentive payments, and employer-based mandates on COVID-19 vaccination rates in New York City: a synthetic-control analysis.

Background: COVID-19 vaccines have been available to all adults in the USA since April, 2021, but many adults remain unvaccinated. We aimed to assess the joint effect of a proof-of-vaccination requirement, incentive payments, and employer-based mandates on rates of adult vaccination in New York City (NYC).

Methods: We constructed a synthetic control group for NYC composed of other counties in the core of large, metropolitan areas in the USA.