Development and application of the vaccine reporting quality score to evaluate the vaccine adverse event reporting system

Ensuring the documentation quality of spontaneous reports in the Vaccine Adverse Event Reporting System (VAERS) is important for signal detection, yet targeted tools for evaluating vaccine-specific reporting quality remain lacking. This study proposes the Vaccine Reporting Quality Score (VRQS)-a transparent, exploratory evaluation system-and applies it to a large-scale VAERS dataset.

The preliminary VRQS aggregates 13 items into two primary domains: Completeness (items 1-10) and Clinical Informativeness (items 11-13), using equal weighting as an initial exploratory index. Using the VAERS 2025 dataset, we established a strict 1-to-1 patient case unit of analysis (N = 40,285 unique case reports) to evaluate demographic, administrative, and clinical density. Multivariable linear and ordinal logistic regressions were executed using independent case characteristics, with all overlapping score components removed a priori to eliminate structural circularity.

The mean overall quality score was 9.04 ± 1.96, with 57.54% of unique reports falling into a medium-quality tier (scores 8-10). Product identifiers, such as vaccine type (97.92%), were highly prevalent, whereas informative laboratory data were present in only 16.18% of records. Distinct, descriptive documentation profiles emerged: spontaneous records displayed high completeness but low informativeness, whereas professional entries and serious adverse events (SAEs) featured dense clinical metrics alongside missing administrative checkfields. In re-specified, non-circular multivariable models, complex clinical factors such as pre-existing allergies (b=0.832, p<0.001) and concurrent medications (b=0.463, p<0.001) were independently associated with higher quality score.

The proposed VRQS framework demonstrates that administrative documentation density does not inherently correlate with clinical informativeness. Rather than acting as a validated tool for causality assessment, the VRQS provides a transparent, preliminary approach for report prioritization and screening pending formal external validation against global benchmarks.