Researchers Study Guaranteed Financial Incentives for COVID-19 Vaccination

Uptake of the COVID-19 vaccine remains too low in the US as COVID-19 variant cases and hospitalizations continue to rise. Nudges that remove barriers and facilitate action can increase vaccine uptake. Many states, North Carolina included, have announced incentive programs to motivate COVID-19 vaccination, including lotteries for $1 million. However, these large but uncertain financial prizes benefit only a few lucky winners and do not broadly address access barriers to vaccination. In contrast, guaranteed small financial incentives can offset costs related to lost wages, transportation, and childcare.

This quasi-experimental study by Wong, et al. (2021) used a two-week pilot incentive program that guaranteed a $25 cash card to adults who either received or drove someone to receive their first dose of COVID-19 at participating sites in four counties in North Carolina. Drivers could earn $25 for each trip but were not paid twice for the same trip (e.g., receiving a vaccine while also bringing someone else). The pilot program distributed 2890 cash cards to vaccine recipients and 1374 to drivers. Analyses of COVID-19 vaccine first doses used a difference-in-differences approach. A competing risk model included constant hazard functions for three defined competing events: being vaccinated at (1) intervention sites, (2) elsewhere in the same 4 counties, and (3) elsewhere in the state. For each event, the model compared different hazards for two baseline periods (April 28-May 11, 2021, and May 12-25, 2021) with the intervention period (June 2-8, 2021); analyses censored the intervening pilot program week owing to staggered site launches in that week. The evaluation also characterized incentive recipients with a cross-sectional survey of vaccine recipients who received a cash card at the intervention sites.

Statistical analysis was performed from June 10, 2021, to August 27, 2021, using R, version 3.6.1 (The R Foundation for Statistical Computing). For the survey analyses, we used Stata, release 15.0 (StataCorp LLC). Tests were 2-tailed and statistical significance was set at P < .05.

Vaccine initiation analyses relied on data aggregated for clinics, thus data on patient race and ethnicity were unavailable. During the baseline periods, COVID-19 vaccine initiation increased in the intervention clinics (46.2%), declined elsewhere in the 4 counties (−9.5%), and increased elsewhere in the state (1.7%; all P < .001; Table 1). From the second baseline period to the intervention period, COVID-19 vaccine initiation declined less at sites offering the guaranteed financial incentive when compared with elsewhere in the same counties (−26.4% vs −51.1%) and the rest of the state (vs −48.6%; both difference-in-differences, P < .001).

Among 401 vaccine recipients surveyed (response rate, 92.4%; mean [SD] age, 41.8 [14.9] years; 207 [52%] women; 187 [47%] Black individuals), 41% reported the cash card was an important reason for vaccination (Table 2). Respondents more commonly identified cash cards as being important if they were of Hispanic ethnicity or other race (OR, 2.00-4.68) rather than White and had lower income (<$40 000 annual) than higher income (ORs, 1.94-2.36). About 9% reported they would not have been vaccinated if the cash card had not been offered, and 15% waited to get vaccinated until they found an event that gave a cash card or other incentive. “Someone driving me here today,” was an important reason for 49% of respondents, more commonly among Black (OR, 1.74; 95% CI, 1.04-2.91), Hispanic (OR, 2.51; 95% CI, 1.32-4.77), and lower income individuals (OR, 2.77-6.09; Table 2). Individuals with lower income (OR, 2.10-3.97) and older individuals (≥50 years; OR, 2.30; 95% CI, 1.33-3.98) were more likely to have been brought by a driver who received a cash card.

Reference: Charlene A. Wong CA, et al. Guaranteed Financial Incentives for COVID-19 Vaccination: A Pilot Program in North Carolina. JAMA Intern Med. Published online October 25, 2021. doi:10.1001/jamainternmed.2021.6170