A quasi-experimental cohort study evaluating a conditional economic incentive on first-dose COVID-19 vaccination rates among older adults in South Africa
Abstract
Importance
COVID-19 vaccination coverage in South Africa remains low despite increased access to vaccines. On November 1, 2021, South Africa 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.
Objective
To evaluate the association of the conditional economic incentive program with first-dose vaccination rates among older adults (aged ≥60 years) in South Africa.
Design
A quasi-experimental cohort study using daily data on first doses administered. We ran interrupted time series (ITS) models to evaluate the Vooma Voucher program, launched on November 1, 2021, at national and provincial levels. We used data between October 1, 2021 and November 27, 2021 in models estimated at the daily level.
Setting and participants
The Vooma Voucher program was a nationwide vaccination incentive program implemented for adults aged ≥60 years from November 1, 2021 to February 28, 2022.
Intervention
Individuals who received their first vaccine dose received a text message to access a ∼$7 (ZAR100) voucher that was redeemable at nationwide chain of grocery stores.
Main outcome
Daily first COVID-19 vaccine doses administered per 10,000 individuals aged ≥60 years.
Results
The Vooma Voucher program was associated with a 7.15-12.01% increase in daily first-dose vaccination in November 2021 compared to late October 2021. 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 weekend initiative (November 12-14), both of which also increased vaccinations through expanded access to vaccines and demand creation activities.
Conclusions/Relevance
Financial incentives for COVID-19 vaccination led to a modest increase in first dose vaccinations among older adults in South Africa. In addition to financial incentives, expanded access to vaccines may also results in higher vaccination coverage.
Trial registration number (SANCTR)
DOH-27-012022-9116
Key Points
Question
What is the association of the Vooma Voucher program with COVID-19 vaccination among older adults in South Africa?
Findings
In this cohort study, a US$7 (ZAR100) incentive for adults aged ≥60 years was associated with a of 7.15-12.01% increase in daily first-dose vaccination in November 2021 compared to late October 2021. The incentive accounted for 6,476-10,874 additional first vaccine doses November 1-27, 2021, or 8.31-13.95% of all doses administered to those aged ≥60 years during that period.
Meaning
Small guaranteed financial incentives may be an effective strategy to increase vaccine demand among older adults in low- and middle-income countries.
Article activity feed
-
SciScore for 10.1101/2022.05.06.22274712: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
NIH rigor criteria are not applicable to paper type.Table 2: Resources
Software and Algorithms Sentences Resources Although the Vooma Voucher program continued until February 28, 2022, the announcement of the Omicron variant on November 24, 2022 would likely confound the effect of the incentive program on days that followed the announcement. Vooma Vouchersuggested: NoneAnalyses were conducted using Stata 17.0 (StataCorp, College Station, TX). StataCorpsuggested: (Stata, RRID:SCR_012763)Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).
Results from LimitationRecognizer: We detected the …SciScore for 10.1101/2022.05.06.22274712: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
NIH rigor criteria are not applicable to paper type.Table 2: Resources
Software and Algorithms Sentences Resources Although the Vooma Voucher program continued until February 28, 2022, the announcement of the Omicron variant on November 24, 2022 would likely confound the effect of the incentive program on days that followed the announcement. Vooma Vouchersuggested: NoneAnalyses were conducted using Stata 17.0 (StataCorp, College Station, TX). StataCorpsuggested: (Stata, RRID:SCR_012763)Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).
Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:A key limitation is the assumption in our ITS models there were no other factors that coincided with the introduction of the Vooma Voucher program and affected vaccine demand. The robustness of our findings to the inclusion of supply and demand creation measures, and to provincial and weekly specifications, increases confidence in our findings. Another limitation is that we only study short-term effects of the incentive program, as the announcement of the Omicron variant made it challenging to study effects of incentives beyond that date. Given the vulnerability of older adults to serious illness, hospitalization, and death as a result of COVID-19, identifying effective strategies to increase vaccine demand is crucial. More generally, as LMICs struggle to achieve sufficiently high vaccine demand despite expansions in vaccine delivery and access, our findings suggest that small financial incentives may be effective in increasing vaccination coverage.
Results from TrialIdentifier: No clinical trial numbers were referenced.
Results from Barzooka: We did not find any issues relating to the usage of bar graphs.
Results from JetFighter: We did not find any issues relating to colormaps.
Results from rtransparent:- Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
- Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
- Thank you for including a protocol registration statement.
Results from scite Reference Check: We found no unreliable references.
Read the original sourceWas this evaluation helpful? -
-