Objectives This study investigated the impact of television news coverage on total adverse event reporting rates 1 month before and after the bulletins during a medication health scare. We further investigated whether individual side effects mentioned in each bulletin were reflected in the adverse event reports following the coverage.

Design A retrospective pre–post observational study.

Setting New Zealand Centre for Adverse Reactions Monitoring.

Participants Adverse events reported from May to December 2008 relating to Eltroxin formulation change.

Primary and secondary outcome measures Primary outcome measure was the total rate of adverse event reporting per day. Secondary outcome measure was the rate of reporting of seven individual symptoms mentioned in the television coverage.

Results After story 1, a significant increase in total reporting rates was evident (Mdn_Pre=0, Mdn_Post=13.5, U=2, p<0.001, r=−0.86) with larger effect sizes for increases in television-mentioned symptoms. Story 2 also showed a significant increase in total adverse event reporting (Mdn_Pre=6, Mdn_Post=18.5, U=86.5, p=0.002, r=−0.49) driven by significant increases only in television-reported symptoms. Story 3 did not result in a significant increase in total reporting (Mdn_Pre=12; Mdn_Post=15.5, U=171, p=0.432, r=−0.12), and showed a significant increase in reporting rates for only one of the two television-reported symptoms.

Conclusions The findings suggest that television news coverage can impact on the overall rate of adverse event reporting during a health scare, in part via increased reporting of media-mentioned side effects. The effects of television media coverage on adverse event reporting appear strongest for earlier reports.