Fatal outcomes following immunization errors as reported to the EudraVigilance: A case series

Area of Science:

• Pharmacovigilance
• Immunization Safety
• Public Health

Background:

• Serious adverse reactions following immunization, though rare, can occur.
• Immunization errors leading to fatal outcomes are exceptionally uncommon but have significant impact.

Purpose of the Study:

• To systematically review immunization errors with fatal outcomes reported in EudraVigilance.
• To assess the causality and contribution of errors to fatal outcomes.

Main Methods:

• Case-series analysis of Individual Case Safety Reports (ICSRs) involving immunization errors and fatalities.
• Utilized the WHO Causality Assessment of an Adverse Event Following Immunization (AEFI) tool.
• Developed a classification to estimate the contribution of errors to fatal outcomes.

Main Results:

• 154 ICSRs met inclusion criteria; pneumococcal, rabies, and influenza vaccines were most frequent.
• Non-compliance with immunization schedules was the most common error.
• Twelve cases showed a consistent causal association with large error contribution, including incorrect multi-dose vial handling and administration of live vaccines to immunocompromised patients.

Conclusions:

• Fatal outcomes associated with immunization errors are very rare.
• Emphasized the importance of quality control for multi-dose vaccines, patient screening for immunocompromising factors, adherence education, and improved vaccine-medicine distinction.