Five Years Later: Did Institutional Trust Predict the Failure of Algeria's COVID-19 Vaccination Campaign? A Retrospective Validation of a 2021 Vaccine Hesitancy Survey

Technical Summary: Five Years Later: Did Institutional Trust Predict the Failure of Algeria's COVID-19 Vaccination Campaign?

Problem Statement
Algeria's COVID-19 vaccination campaign failed to approach the World Health Organization's (WHO) 70% herd-immunity target, plateauing at less than 20% of the population fully vaccinated. While cross-sectional surveys conducted in 2021 indicated extremely low acceptance (11.4%), it remained unclear whether these stated intentions accurately predicted actual behavior or if the "intention-behaviour gap" would widen as the pandemic evolved. The central problem addressed is distinguishing between two competing drivers of hesitancy: complacency (low perceived disease risk, which should diminish as severity becomes apparent) versus confidence (institutional distrust, which is more durable). The study seeks to retrospectively validate whether the 2021 survey's trust-centric findings predicted the long-term stagnation of vaccination coverage.

Methodology
This study employs a retrospective validation design, comparing previously published attitudinal data against aggregate national outcomes over a five-year period (2021–2023).

• Baseline Data: The analysis utilizes data from Chami and Lahrache (2022), a cross-sectional survey of 1,600 Algerian residents conducted between September and December 2021. This survey measured stated vaccination intentions, trust in health authorities, and risk perception.
• Outcome Data: National vaccination coverage figures were sourced from the WHO African Region, Our World in Data, and covidvax.live for the period spanning late 2021 to October 2023.
• Comparative Framework: To determine if Algeria's trajectory was unique or regional, the study descriptively compares Algeria's data with four MENA comparator countries (Jordan, Tunisia, Egypt, and Kuwait) for which similar early acceptance and eventual coverage data exist.
• Analytical Approach: The study is ecological (population-level) rather than individual-level, as individual survey respondents cannot be matched to vaccination records. The analysis focuses on the concordance between the 2021 stated acceptance rate and the eventual coverage plateau, as well as the shape of the coverage trajectory (steady climb vs. early plateau).

Key Results

• Predictive Validity of Stated Intention: The 2021 stated acceptance rate of 11.4% closely anticipated the eventual coverage plateau of 17.8% (fully vaccinated) reached by mid-2022 and maintained through 2023. The narrow gap between intention and behavior suggests that the initial attitudes were highly predictive in this context.
• Trajectory Shape: Vaccination coverage rose quickly to approximately 15–18% but then flattened significantly, showing no further substantial growth through 2023. This "early rise, long plateau" shape contradicts a complacency-based model (which would predict rising acceptance as disease severity increased) and supports a confidence-based model where distrust acts as a persistent structural barrier.
• Regional Contrast: The study found that the tight alignment between low intention and low outcome was specific to Algeria. In contrast, Jordan, which had similarly low initial acceptance (28.4% in late 2020), achieved nearly triple that coverage (~49.5%) by 2022. This suggests that in Jordan, external interventions (mandates, trust-building communication) successfully widened the intention-behaviour gap, whereas in Algeria, the absence of such interventions allowed initial attitudes to persist.
• Drivers of Hesitancy: The results retrospectively confirm the original study's rejection of the risk-perception hypothesis (H1) and confirmation of the trust hypothesis (H2). The persistence of the plateau despite accumulating global safety data indicates that institutional distrust, rather than fear of side effects or lack of information, was the primary driver.

Key Contributions

• Retrospective Validation: This is one of the first studies to retrospectively validate a COVID-19 vaccine hesitancy survey against multi-year national coverage data within the MENA region. It demonstrates that in low-trust environments, stated intentions can carry significant predictive weight regarding long-term uptake.
• Refining the Intention-Behaviour Gap: The paper contributes to health psychology literature by showing that the size of the intention-behaviour gap is not fixed; it depends on intervening factors. In the absence of mandates or trust-rebuilding efforts, the gap remains narrow, and initial attitudes drive behavior.
• Differentiation of Hesitancy Models: The study provides empirical evidence distinguishing between "complacency" and "confidence" as drivers of hesitancy. It argues that in Algeria, the barrier was not a lack of information about disease severity (which was rising during the study period) but a durable deficit in institutional trust.

Significance and Claims
The paper claims that the durability of Algeria's vaccination plateau lends retrospective support to trust, rather than risk perception, as the true driver of hesitancy. It argues that in settings characterized by low institutional trust, standard public health interventions focused on increasing disease severity information or vaccine efficacy data are unlikely to shift attitudes. Instead, the findings suggest that without active trust-building or structural interventions (such as mandates), initial hesitancy will likely persist, resulting in a vaccination campaign that fails to reach herd immunity targets. The study concludes that for future pandemic preparedness and routine immunization, rebuilding trust is a more critical, albeit slower, prerequisite for success than merely closing information gaps.