Predictors of COVID-19 vaccine uptake: An online longitudinal study of US Veterans and non-Veterans

  1. Alistair Thorpe
  2. Angela Fagerlin
  3. Frank A. Drews
  4. Holly Shoemaker
  5. Federica S. Brecha
  6. Laura D. Scherer

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Abstract

Background

To effectively promote vaccine uptake, it is important to understand which people are most and least inclined to be vaccinated and why.

Purpose

To identify predictors of COVID-19 vaccine uptake and reasons for non-vaccination.

Design

A longitudinal English-language survey study.

Setting

Online in December-2020, January-2021, and March-2021. Participants. 930 US respondents (63% Veterans).

Measurements

Surveys included questions about respondents’ behaviors, well-being, healthcare experiences, and attitudes regarding the pandemic.

Results

The proportion of respondents who received ≥1-dose of a COVID-19 vaccine increased from 18% in January to 67% in March. Older age predicted vaccine uptake in January (OR=2.02[95%CI=1.14–3.78], p <.001) and March (10.92[6.76–18.05], p <.001). In January, additional predictors of vaccine uptake were higher numeracy (1.48[1.20–1.86], p <.001), COVID-19 risk perceptions (1.35[1.03–1.78], p =.029), and believing it is important that adults get the COVID-19 vaccine (1.66[1.05–2.66], p =.033). In March, additional predictors of vaccine uptake were believing it is important that adults get the COVID-19 vaccine (1.63[1.15–2.34], p =.006), previous (January) COVID-19 vaccine intentions (1.37[1.10–1.72], p =.006), and belief in science (0.84[0.72–0.99], p =.041). Concerns about side effects and the vaccine development process were the most common reasons for non-vaccination. Unvaccinated respondents with no interest in getting a COVID-19 vaccine were younger (0.27[0.09–0.77], p =.016), held negative views about COVID-19 vaccines for adults (0.15[0.08–0.26], p <.001), had lower trust in healthcare (0.59[0.36–0.95], p =.032), and preferred to watch and wait in clinically ambiguous medical situations (0.66[0.48–0.89], p =.007).

Limitations

Reliance on the accuracy and consistency of self-reported data.

Conclusion

These findings offer important insights regarding key predictors of vaccine uptake during the early stages of the COVID-19 vaccine rollout in the US, which can help guide health communications and public outreach. Evidence that attitudes and intentions towards COVID-19 vaccines are important predictors of uptake provides validation for studies which have used these measures and reinforces the need to develop effective strategies for addressing concerns about vaccine safety and development which continue to be at the forefront of vaccine hesitancy.

Registration

The pre-registration document associated with this manuscript is available at: https://aspredicted.org/MKS_HRZ .

Article activity feed

  1. Version published to 10.1101/2022.04.19.22273818v2 on medRxiv
  2. ScreenIT

    SciScore for 10.1101/2022.04.19.22273818: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    Ethicsnot detected.
    Sex as a biological variableRespondents in our sample were generally older (median age ranged between 55 and 74 years old), male (735 (79%)), non-Hispanic White (720 (77%)), US Veterans (584 (63%)), and with a median household income between $50,000-$99,999.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.

    Table 2: Resources

    Experimental Models: Organisms/Strains
    SentencesResources
    Respondents in our sample were generally older (median age ranged between 55 and 74 years old), male (735 (79%)), non-Hispanic White (720 (77%)), US Veterans (584 (63%)), and with a median household income between $50,000-$99,999.
    non-Hispanic White
    suggested: None

    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:
    One limitation of the study is that the findings rely on the accuracy and consistency of respondents’ self-reported data over the duration of the survey period. Although self-reports have been shown to be highly concordant with healthcare utilization and vaccine records,44,45 replication of these findings with a method for confirming respondents’ reported vaccine uptake would increase confidence in these findings. Furthermore, our sample consisted of Veteran and non-Veteran respondents who were unique in being sufficiently motivated and able to complete three online surveys during the pandemic and therefore are not representative of the general U.S. population. The finding that Veteran status did not predict vaccine uptake at either time point was surprising given the efforts and widespread outreach of the U.S. Department of Veterans Affairs in supporting COVID-19 vaccine distribution.46 However, it is likely that the greater proportion of older adults in the Veteran sample compared to the non-Veteran sample may have limited our ability to observe a significant effect of Veteran status in the full model. In addition, our sample was overrepresented by respondents without many health conditions (70% reported ≤ 1 health condition), with high health literacy (94% of respondents reported high health literacy), and who identified as non-Hispanic White (78%). The unique makeup of our sample may also explain why older age and numeracy were the only early eligibility and demographic f...

    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.
    • No protocol registration statement was detected.

    Results from scite Reference Check: We found no unreliable references.

    About SciScore

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  3. Version published to 10.1101/2022.04.19.22273818v1 on medRxiv