https://www.sciencedaily.com/releases/2021/07/210702154302.htm > Prior reports in the media had suggested that the Ohio lottery increased COVID-19 vaccinations, leading other states to use COVID-19 vaccine incentive lotteries in an attempt to increase slowing vaccination rates. "However, prior evaluations of the Ohio vaccine incentive lottery did not account for other changes in COVID-19 vaccination rates in the United States, such as those that may have been due to expansion of vaccination to ages 12-15," explained corresponding author Allan J. Walkey, MD, MSc, professor of medicine at BUSM. > Using data from the U.S. Centers of Disease Control to evaluate trends in vaccination rates among adults 18 and older, the researchers compared vaccination rates before and after the Ohio lottery versus other states in the U.S. that did not yet have vaccine incentive lottery programs. Vaccination rates in other states served as a "control" for vaccination trends measured in Ohio, allowing the researchers to account for factors besides the Ohio lottery (such expanding vaccine eligibility to adolescents) throughout the country.