麻豆传媒

COVID-19 vaccine lottery incentive programs had no significant increase on state vaccination rates or trends, researchers found.

Compared with pre-lottery patterns, lottery states showed no significant change in vaccination trends (0.7 per 100,000 people each day, 95% CI -0.9 to 2.4), nor a significant increase in vaccine administration (-0.4 per 100,000 people, 95% CI -23.5 to 22.7), reported Anica C. Law, MD, MS, of the Boston University School of Medicine, and colleagues.

Moreover, compared to non-lottery states, there was no significant change in vaccination level (1.1 per 100,000 people, 95% CI -21.7 to 23.8, P=0.92), nor a significant change in the vaccination rate trend (0.4 per 100,000 people each day, 95% CI -1.1 to 2.0, P=0.59), the authors wrote in a research letter published in .

"We previously found that Ohio's lottery system to incentivize vaccination was not associated with increased vaccinations," Law told 麻豆传媒. "Since it was unclear if other states might have different responses to lottery vaccine incentives, we assessed changes in COVID-19 vaccination rates in 15 other states with subsequent lottery programs."

Prior reports indicated that vaccine incentive lottery success has varied by state and was only associated with a minimal increase in vaccinations, and Law and colleagues characterized the relationship between state vaccination rates and lottery programs as "unclear."

They evaluated CDC data on adult first-dose vaccinations from May 17 to July 26, 2021 across 15 states that provided cash prizes in exchange for COVID-19 vaccinations (lottery states) and 31 non-lottery states.

The main outcomes assessed immediate changes in vaccination rates, and daily vaccination rates among lottery states compared to differences in vaccination rates or trends in non-lottery states after the incentive program was announced.

Both lottery and non-lottery states had similar vaccination rates within 4 weeks prior to announcing the lottery (-0.5 vaccinations per 100,000 people each day, 95% CI -1.7 to 0.82, P=0.69).

Lottery states had decreases in vaccination rates prior to announcing their vaccine incentive program (-2.8 per 100,000 people each day, 95% CI -4.2 to -1.4), but did not show any significant vaccine uptake after the lottery was announced, Law and colleagues wrote.

"A sensitivity analysis of states with more than 3 weeks of pre-lottery data found no significant difference in vaccination levels and a borderline significant increase in trend after lottery announcements," the authors noted.

The analysis had several limitations, the researchers acknowledged, including the use of statistical modeling, which could be underpowered to detect minor increases in vaccination rates. Results were also based on vaccine data reported to the CDC.

They concluded that further studies of strategies to increase vaccination rates are needed.

"Our results suggests that state-based lotteries are of limited value in increasing COVID-19 vaccine uptake," Law said.

Comment