BACKGROUND:
Media events are thought to influence the reporting rate of passive surveillance systems, such as the Vaccine Adverse Events Reporting System (VAERS). Intense media coverage surrounding the Department of Defense (DoD) Anthrax Vaccine Immunization Program (AVIP) provided an opportunity to investigate.

OBJECTIVE:
To examine if there is a relationship between frequency of media reports on the anthrax vaccine and later VAERS reporting rates

METHOD:
1648 anthrax VAERS reports relating to 2,230,454 anthrax vaccinations in registries in the Defense Medical Surveillance System (DMSS) were made between 1 January 1998 and 30 June 2001. During this time the Lexis-Nexis database listed 8227 anthrax vaccine publicity events. We used linear regression and test of trend to assess the relationship between anthrax vaccine publicity frequency and rates of reporting of anthrax VAERS, Anthrax Vaccine Expert Committee (AVEC) determination of causality and Food and Drug Administration (FDA) assessments of severity. We also used analysis of variance (ANOVA) to test for a difference in the mean time of VAERS reporting.

RESULT:
Anthrax vaccine publicity frequency was significantly (Pearson's R= .73, p<.01) positively associated with anthrax VAERS reporting rates. When publicity doubled, VAERS reporting rates increased by a factor of 1.59. There was also a positive (Pearson's R=.69, p=.01) association with AVEC causality assessment of “Very Likely” and FDA “Non-Serious” adverse events (Pearson's R=.68, p<. 01). Additionally, FDA “Serious” vaccine events showed a significantly shorter mean interval between date of reaction and filing compared to “Non-Serious” events (mean difference 10 days, p<.05), but reporting delays varied widely (range: 0 to 884 days).

CONCLUSION:
Increased publicity regarding the anthrax vaccine is positively correlated to the rate of anthrax VAERS reporting, with variable effects by category, but this ecologic study cannot determine if the relationship is causal.

LEARNING OBJECTIVES:
Describe the effect of publicity on anthrax VAERS reporting.