A quasi-experimental cohort study evaluating a conditional economic incentive on first-dose COVID-19 vaccination rates among older adults in South Africa

IntroductionCOVID-19 vaccination coverage in South Africa (RSA) remains low despite increased access to vaccines. On November 1, 2021, RSA introduced the Vooma Voucher program which provided a small guaranteed financial incentive, a Vooma Voucher redeemable at grocery stores, for COVID-19 vaccination among older adults, a population most vulnerable to serious illness, hospitalization, and death. However, the association of financial incentives with vaccination coverage remains unclear. MethodsWe evaluated the association of the conditional economic incentive program with first-dose vaccination rates among adults (aged [≥]60 years) through a quasi-experimental cohort study. The Vooma Voucher program was a nationwide vaccination incentive program implemented for adults aged [≥]60 years from November 1, 2021 to February 28, 2022. We ran interrupted time series models to evaluate the Vooma Voucher program at national and provincial levels. We used data between October 1, 2021 and November 27, 2021 in models estimated at the daily level. Individuals who received their first vaccine dose received a text message to access a ZAR100 ($[~]7) voucher that was redeemable at grocery stores. ResultsThe Vooma Voucher program was associated with a 7.15-12.01% increase in daily first-dose vaccinations in November 2021 compared to late October 2021. Overall, the incentive accounted for 6,476-10,874 additional first vaccine doses from November 1-27, 2021, or 8.31-13.95% of all doses administered to those aged [≥]60 years during that period. This result is robust to the inclusion of controls for the number of active vaccine delivery sites and for the nationwide Vooma vaccination weekend initiative (November 12-14), both of which also increased vaccinations through expanded access to vaccines and demand creation activities. ConclusionsFinancial incentives for COVID-19 vaccination led to a modest increase in first dose vaccinations among older adults in RSA. Financial incentives and expanded access to vaccines may result in higher vaccination coverage. Trial registration number (SANCTR)DOH-27-012022-9116 Key points (3-5 sentences)O_ST_ABSWhat is already known about this topic?C_ST_ABSThere is a lack of evidence on whether financial incentives for COVID-19 vaccinations are effective in low- and middle-income countries. What does this study add?We found that a ZAR100 ([~]US$7) incentive for adults aged [≥]60 years increased additional first vaccine doses between November 1-27, 2021 to those aged [≥]60 years during that period. How this study might affect research, practice or policy?Small guaranteed financial incentives may be an effective strategy to increase vaccine demand among older adults in low- and middle-income countries.