This prospective cohort analysis examined whether experiencing adverse events (AE) after a COVID-19 booster dose was associated with reduced likelihood of receiving a subsequent booster during the 2022–2024 autumn campaigns in the Netherlands. The study used data from the Vaccine Study COVID-19 (VASCO) cohort and focused on the occurrence, severity, and duration of local and systemic AE reported one month after booster vaccination.
Participants were drawn from VASCO, an ongoing prospective cohort study in the Netherlands. Individuals who received a booster dose in 2022 or 2023 and completed the one-month post-booster AE questionnaire were included in the analyses. Key exposure variables were the occurrence of local and systemic AE, graded by severity (including categories for moderate and severe) and by duration (including a category for AE lasting more than five days).
The primary outcome was revaccination (receipt of a subsequent booster) during the following autumn campaign year. Logistic regression models estimated associations between AE measures and revaccination, adjusting for demographic characteristics and prior SARS-CoV-2 infection. The authors reported odds ratios (ORs) with 95% confidence intervals (CIs). The primary comparisons reported in the abstract focused on AE after the 2022 booster and revaccination in 2023, with similar analyses performed for 2023→2024.
Sample sizes were 11,010 participants vaccinated in 2022 who completed the AE questionnaire and 14,824 participants vaccinated in 2023 who completed the questionnaire. Revaccination rates in the subsequent years were reported as 73.7% for those vaccinated in 2022 (revaccinated in 2023) and 87.0% for those vaccinated in 2023 (revaccinated in 2024).
Key associations included:
The occurrence of systemic AE after the 2022 booster was associated with lower odds of revaccination in 2023 (OR 0.84; 95% CI, 0.76–0.93).
Severity of systemic AE showed a dose-response relationship with uptake: participants reporting moderate systemic AE had lower odds of revaccination (OR 0.79; 95% CI, 0.66–0.94), while those reporting severe systemic AE had substantially lower odds (OR 0.45; 95% CI, 0.34–0.60).
Longer duration of systemic AE was associated with reduced revaccination: AE lasting more than five days was linked to lower odds of revaccination (OR 0.72; 95% CI, 0.54–0.95).
Severe local AE were also associated with reduced uptake (OR 0.38; 95% CI, 0.23–0.60).
Seeking medical care for AE correlated with lower likelihood of revaccination (OR 0.50; 95% CI, 0.34–0.73).
The abstract notes that similar associations were observed for revaccination in 2024 following AE reported in 2023, though the abstract provides detailed ORs primarily for the 2022→2023 comparisons.
In this large prospective cohort, experiencing post-booster AE—especially systemic AE that were moderate, severe, or prolonged—was associated with a decreased probability of receiving a subsequent COVID-19 booster dose. Severe local AE and AE that prompted medical attention were also linked to lower subsequent uptake. The patterns reported suggest that both the presence and the burden (severity, duration, health-care seeking) of AE influence later vaccination behavior.
These findings are consistent with the hypothesis that personal experience of vaccine-related AE can affect acceptance of future doses. The observed dose-response pattern with increasing severity and longer duration of systemic AE strengthens the plausibility of a causal relationship between AE burden and lower booster uptake, although observational design precludes definitive causal inference.
The authors emphasize the importance of addressing experienced AE in public health messaging and communication strategies. Acknowledging and contextualizing common post-vaccination reactions, advising on expected duration, and providing clear guidance about when to seek care may help mitigate the negative impact of AE experiences on subsequent booster acceptance. Targeted communication may be particularly relevant for people who experienced severe or prolonged reactions or who required medical attention.
The abstract does not provide full methodological detail on potential biases, measurement methods beyond the one-month questionnaire, or subgroup analyses; such details were not reported in the abstract. As an observational cohort study, residual confounding and self-reporting biases are possible, and causality cannot be established from the reported results alone.
This VASCO cohort analysis found that experiencing post-booster systemic adverse events, particularly when moderate, severe, or prolonged, as well as severe local AE or AE requiring medical care, was associated with lower likelihood of obtaining subsequent COVID-19 booster doses in the Netherlands. The authors conclude that public health strategies should explicitly address experienced AE to support future vaccination campaign uptake.