Vaccine Vigilance System: Considerations on the Effectiveness of Vigilance Data Use in COVID-19 Vaccination.

Observed Findings

• General disorders and administration site conditions were the most frequently reported adverse reaction category.
• Nervous system disorders were among the three most commonly reported categories following vaccination.
• Musculoskeletal and connective tissue disorders constituted a major proportion of reported adverse reactions.
• mRNA vaccines had higher absolute numbers of reported adverse reactions, but lower relative frequency per dose administered compared to other vaccine types.
• Chronic fatigue syndrome reports were present in the EudraVigilance database but specific ME/CFS data were not systematically tracked.

Inferred Conclusions

• The current passive pharmacovigilance system may have limitations in detecting and rapidly communicating safety signals during large-scale vaccination campaigns.
• Active pharmacovigilance models incorporating modern data technologies and social media analysis could improve early detection of potential adverse reaction patterns.
• Healthcare professionals need more rapid access to organized safety information categorized by organ system during mass vaccination periods.
• Future vaccine safety monitoring should include structured tracking of post-viral-like syndromes including ME/CFS.

Remaining Questions