Myth: Thimerosal (mercury) in vaccines causes autism

Thimerosal & Autism: The Non-Connection

### What is Thimerosal?

Thimerosal is an ethyl mercury compound used as a preservative in multi-dose vaccine vials (not single-dose). It was never in live vaccines like MMR.

### Removal Proved No Link

Thimerosal removed from US childhood vaccines by **2002**

Autism diagnoses **continued rising** after removal (2002-2020)

If mercury caused autism, we'd expect diagnoses to **decline** after removal

They didn't — which is the strongest natural experiment

### Mercury Levels Were Never Toxic

Peak infant exposure: ~6 μg/kg (within EPA safety guidelines of 71 μg/kg)

Ethyl mercury is excreted quickly (vs toxic methyl mercury)

Never accumulated in the body

### High-Quality Studies Found No Link

**Verstraeten et al. (2003)**: 125,000+ vaccinated children — no autism association

**Hviid et al. (2003)**: Danish cohort of 440,000 — no link even after increasing thimerosal exposure

### Current Status

Thimerosal remains in some flu vaccines as a preservative in multi-dose vials. Single-dose syringes are thimerosal-free. No evidence supports removing it further.

📚 Research Sources

Verstraeten T, Destefano F, Baughman AL, et al. (2003)

"Thimerosal, the hepatitis B vaccine, and autism"

American Journal of Preventive Medicine

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Thimerosal was removed from childhood vaccines in the US by 2002 due to precaution, yet autism diagnoses continued to increase after its removal—proving no causal link.

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Thimerosal & Autism: The Non-Connection

📚 Research Sources

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