Dataset Information

Will Americans Get Vaccinated? Predicting COVID-19 Vaccine Uptake Rates Under Contingent Scenarios

ABSTRACT:

Objectives

Amid a pandemic, vaccines represent a promising solution for mitigating public health and economic crises, and an improved understanding of individuals’ vaccination intentions is crucial to design optimal immunization campaigns. This study predicts uptake rates for different COVID-19 vaccine specifications and identifies personal characteristics that moderate an individual’s responsiveness to vaccine attributes.

Methods

We developed an online survey with contingent specifications of a COVID-19 vaccine, varying in effectiveness, risks of side effects, duration of immunity, and out-of-pocket cost. Using population-averaged logit models, we estimated vaccine uptake rates that account for uncertainty, heterogeneity across respondents, and interactions between vaccine and personal characteristics.

Results

We obtained 3047 completed surveys. The highest uptake rate for an annual vaccine, 62%, is predicted when vaccine effectiveness is 80% to 90%, side effects are minimal, and the vaccine is provided at zero cost, with decreases seen in the uptake rate for less effective vaccines, for example, 50% for 50% to 60% effectiveness. Moreover, we found that Americans’ response to vaccine effectiveness depends on their self-reported concern, that is, concerned respondents report a higher willingness to get vaccinated. Our findings also indicate that COVID-19 vaccine uptake rates decrease with vaccine cost and that responsiveness to vaccine cost is moderated by income.

Conclusions

Although providing the COVID-19 vaccine at zero cost will motivate many individuals to get vaccinated, a policy focused exclusively on vaccine cost may not be enough to reach herd immunity thresholds. Although those concerned with COVID-19 will participate, further evidence is needed on how to incentivize participation among the unconcerned (43%) to prevent further pandemic spread.

SUBMITTER: Vasquez W

PROVIDER: S-EPMC8339597 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:ObjectiveTo assess the impact of increasing incentive size and reminder calls on the measles vaccine uptake rate.DesignRandomized controlled trial, randomized at individual level, stratified by clinic.SettingNigeria.Participants1088 caregivers with children aged nine months or older; had received at least one previous conditional cash transfer (CCT) at a program clinic, had received their Penta-3 immunization but had not yet received their measles immunization, and the caregiver had provided a phone number.InterventionNine clinics were randomized to two models; caregivers in Model 1 received a default of 2000 Nigerian Naira (NGN) for completing the measles vaccine, and those in Model 2 received by 3000 NGN. Caregivers from the respective clinics were then randomized to one of the four arms: 1) control (baseline amount of 2000 NGN or 3000 NGN), 2) baseline amount plus a reminder call, 3) baseline amount plus 1000 NGN and a reminder call, and 4) baseline amount plus 3000 NGN and a reminder call.Main outcome measureReceipt of measles vaccine as reported on a child health card.ResultsOverall, there was no clear trend that increasing the incentive amount resulted in an increase in vaccine uptake rates. In Model 1 households, an additional 1000 NGN and 3000 NGN resulted in a 6.4 percentage point (95% CI: -2.3-15, p-value = 0.15) and 11.8 percentage point (95% CI: 3.9-19.6, p-value = 0.003) increase in the probability of completing the measles vaccines, respectively. This increase, however, was only significant for the 3000 NGN increase. On the other hand, in Model 2 households, increasing the incentive by 1000 NGN and 3000 NGN increased the probability by 3.3 (95% CI: -3.8-10.4, p-value = 0.36) and 3.3 (95% CI: -3.7-10.4, p-value = 0.35) percentage points. These increases were not statistically significant. Adding reminder calls to CCTs increased the probability of completing the measles vaccine; caregivers who received reminder calls plus CCTs were 5.1 percentage points more likely to get their children vaccinated (95% CI: 0.50-9.8, p-value = 0.03) compared to those who received CCTs and did not receive a reminder call. These results were largely driven by caregivers who went to clinics in Model 1.ConclusionA combination of increasing incentive amounts and reminder calls modestly improves measles immunization rates. However, this program also shows that there is substantial regional heterogeneity in response to both incentives and calls. While one possible conclusion is that a larger incentive and phone reminders are more likely to work in higher income and higher baseline coverage settings, the study is not designed to evaluate this claim. Rather, policymakers could consider experimenting with a similar low-cost calling study as part of the design of other cash transfer programs to identify whether adding reminder phone calls could increase the impact of the program.