a catalogue of documented anomalies on planet Earth // maintained by the Aliens
> RECORD OBS-0548 | status: DEBUNKED | filed 2026-07-31
Home > Health > Thiomersal (mercury) in vaccines causes autism

Thiomersal (mercury) in vaccines causes autism

RecordOBS-0548
CategoryHealth/Vaccines
StatusDEBUNKED
SummarySome anti-vaccine proponents claim that the mercury-based preservative thiomersal, used in some vaccines, causes autism. This claim is often linked to the MMR vaccine myth, though thiomersal was never used in the MMR vaccine. Scientific studies have found no evidence supporting a link between thiomersal and autism.
OriginThe claim emerged in the late 1990s and early 2000s, partly due to concerns about mercury exposure and the increasing prevalence of autism diagnoses.
Claimed
  • Thiomersal, a mercury-containing preservative in vaccines, causes autism.
  • The increase in autism diagnoses is due to the use of thiomersal in childhood vaccines.
Evidence / consensusMultiple studies and reviews have found no link between thiomersal in vaccines and autism. Thiomersal was removed from most childhood vaccines in the U.S. and Europe, but autism rates did not decline, further refuting the claim.
> OBSERVER NOTE:
Often conflated with the MMR myth, but thiomersal was never in the MMR vaccine. The claim persists despite lack of evidence and the fact that autism rates continued to rise after thiomersal was removed.

Sources

  1. Vaccination as a cause of autism-myths and controversies - PMC

Sources are external and provided for verification. Listing does not imply the Observer endorses their claims.