Fact Check: Only 0.3% of flu vaccine doses contained thimerosal in 2024.

Fact Check: "Only 0.3% of flu vaccine doses contained thimerosal in 2024."

What We Know

The claim that "only 0.3% of flu vaccine doses contained thimerosal in 2024" requires careful examination of the available data on thimerosal in vaccines. According to the CDC, thimerosal is an ethyl mercury-based preservative used primarily in multi-dose vials of vaccines to prevent contamination. Most flu vaccines in the United States are now thimerosal-free, particularly single-dose vials and pre-filled syringes, which are designed for single use and do not require preservatives.

Data from the CDC indicates that during the 2024-2025 flu season, approximately 96% of all influenza vaccines administered in the United States were thimerosal-free. This suggests that only a small fraction of flu vaccines contained thimerosal, but the exact percentage is not explicitly stated as 0.3%.

Additionally, the Thimerosal in Flu Vaccine page emphasizes that thimerosal is still present in some multi-dose vials, but the prevalence of thimerosal-containing vaccines has significantly decreased over the years due to public health policies and consumer demand for thimerosal-free options.

Analysis

The claim's accuracy hinges on the specific percentage of flu vaccine doses that contained thimerosal in 2024. The CDC's data indicates that while thimerosal is present in some multi-dose formulations, the overwhelming majority of flu vaccines are now thimerosal-free. The assertion that only 0.3% of doses contained thimerosal lacks direct support from the data provided by the CDC, which states that 96% of vaccines were thimerosal-free, implying that the percentage of thimerosal-containing doses is much higher than 0.3%.

Moreover, the source of the claim is not clearly identified, making it difficult to assess its reliability. The CDC and other reputable health organizations are generally considered reliable sources of information regarding vaccine safety and composition. However, without a clear citation or reference to the origin of the 0.3% figure, it remains unverified.

The Thimerosal-Containing Vaccines and Autism review also discusses the historical context of thimerosal in vaccines, noting that its use has been reduced significantly due to safety concerns. This further supports the notion that while thimerosal is still present in some vaccines, its prevalence has dramatically decreased.

Conclusion

Needs Research. The claim that "only 0.3% of flu vaccine doses contained thimerosal in 2024" lacks sufficient evidence to be validated. While it is clear that the majority of flu vaccines are now thimerosal-free, the specific percentage cited is not corroborated by reliable sources. Further investigation and clarification of the source of this statistic are necessary to determine its accuracy.