Does the Tetanus and Diphtheria (Td) vaccine contain thimerosal?

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Last updated: March 28, 2025View editorial policy

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From the Guidelines

The Td vaccine is thimerosal-free, as stated in the 2018 study published in MMWR Recommendations and Reports 1. The formulation of the Td vaccine in the United States is adsorbed to aluminum salt adjuvants and is highly purified, with less than 0.02% formaldehyde and less than 1.25 mg aluminum per dose. Some key points to consider about the Td vaccine include:

  • The vaccine is available in combination with diphtheria toxoid, with or without whole-cell pertussis antigens.
  • Adolescent and adult formulations of the vaccine contain less than or equal to 5 limit of flocculation units of tetanus toxoid per 0.5 ml dose.
  • More than a single dose of the vaccine is required to induce immunologic protection, and booster doses are required to maintain protection, as noted in the study 1. The use of thimerosal as a preservative in vaccines has been a topic of discussion, but the Td vaccine is specifically stated to be thimerosal-free in the 2018 study 1. Some additional considerations about thimerosal include:
  • Thimerosal is a mercury-containing compound that has been used as a preservative in vaccines since the 1930s.
  • Extensive scientific research has not found evidence that the low levels of thimerosal in vaccines cause harm, except for minor reactions like redness and swelling at the injection site. However, the most recent and highest quality evidence from the 2018 study 1 confirms that the Td vaccine is thimerosal-free, which is the primary consideration for patients and healthcare providers.

From the FDA Drug Label

This product contains no preservative The Tetanus and Diphtheria (Td) vaccine does not contain thimerosal, as it is stated that the product contains no preservative 2.

  • Key ingredients include tetanus toxoid, diphtheria toxoid, aluminum phosphate, and residual formaldehyde.
  • No mention of thimerosal is made in the drug label.

From the Research

Thimerosal Content in Td Vaccine

  • The provided studies do not directly address the presence of thimerosal in the Tetanus and Diphtheria (Td) vaccine 3, 4, 5, 6, 7.
  • Studies 3 and 4 discuss the development and immunogenicity of DTP and Tdap vaccines, but do not mention thimerosal.
  • Study 5 compares the safety and immunogenicity of thimerosal-free and thimerosal-containing hepatitis B vaccine formulations, but does not relate to the Td vaccine.
  • Study 6 investigates the risk of neurodevelopmental disorders following Thimerosal-containing Hib vaccine, which is not relevant to the Td vaccine.
  • Study 7 analyzes post-vaccination reactions and complications of pertussis, diphtheria, and tetanus vaccines, but does not provide information on thimerosal content in the Td vaccine.

Available Information

  • There is no direct evidence in the provided studies to confirm or deny the presence of thimerosal in the Td vaccine 3, 4, 5, 6, 7.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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