Polyarteritis nodosa reports to the Vaccine Adverse Event Reporting System (VAERS): Implications for assessment of suspected vaccine-provoked vasculitis

Objective. To examine polyarteritis nodosa (PAN) reports to the Vaccine Adverse Event Reporting System (VAERS) as the initial stage in investigating the hypothesis that vaccination can very rarely cause PAN. Methods. We reviewed PAN reports submitted from 1990 through 2001 using a causal inference framework to evaluate the consistency of the reports' clinical details with this hypothesis. We also reviewed published literature relating to the hypothesized association's biological plausibility. Results. VAERS received 25 PAN reports. Ten met our case definition for definite or possible PAN and had no alternative etiology for PAN identified. Nine of these 10 followed hepatitis B vaccine with a modal peak (4 definite cases) in time to symptom onset 2 weeks after vaccination. However, all potential triggering infections were not excluded, and identification of vaccine antigens in clinical specimens was not attempted. Also, 14 of 25 reports were European, with 11 from France. All 9 French reports with a known diagnosis date began during 1994-97, when autoimmune and rheumatologic events following hepatitis B vaccine were a focus of public concern in France. Conclusion. While we identified some supportive evidence, overall, current adverse event reports do not support a causal link between vaccination and PAN. Appropriate prospective evaluation of future post-vaccination PAN cases could add to current knowledge with rigorous confirmation of diagnosis, appropriate testing for possible triggering infections including polymerase chain reaction testing for latent hepatitis B infection, and an attempt to link the vaccine antigen to pathology such as by immunohistochemical staining or immune complex identification.