A vaccine ingredient has become the focus of attention as a preservative known as thimerosal was included on the agenda for a meeting of the CDC’s Advisory Committee on Immunization Practices (ACIP). The committee’s agenda listed a presentation on thimerosal in vaccines, followed by proposals regarding thimerosal-containing influenza vaccine. Thimerosal, a mercury-based preservative, has been used in multi-dose vaccines and medications since the 1930s to prevent contamination. According to the CDC, the preservative is intended to prevent bacterial and fungal growth.
As growing concerns about potential mercury exposure have led to a decision to reduce or eliminate thimerosal in vaccines, the American Academy of Pediatrics, Public Health Service agencies, and vaccine manufacturers agreed that thimerosal should be reduced or eliminated. In 2001, thimerosal was removed from all vaccines recommended for children aged 6 and younger, except for influenza. Today, multi-dose flu vaccines still contain thimerosal, but other versions are available without the ingredient.
At the June 27 meeting, the CDC’s Advisory Committee on Immunization Practices voted to recommend that all adults (including pregnant women) and all children 18 years and younger should receive seasonal influenza vaccines in single-dose formulations that do not contain thimerosal. The committee’s recommendation came despite the CDC and other health agencies stating there is no evidence of health risks from thimerosal. The CDC’s website states that the use of thimerosal in medical products has a record of being very safe, with no evidence of harm caused by the low doses in vaccines.
Dr. Jacob Glanville, CEO of Centivax, a San Francisco-based biotechnology company, noted that American children have not been receiving thimerosal in their vaccines for over 20 years, but it remains in some multi-use vial vaccines, mostly outside the U.S. He supported efforts to remove thimerosal entirely and pointed out that there are alternative preservatives not based on mercury. Glanville also mentioned that his company’s vaccines never contain mercury, aluminum, formaldehyde, or animal-derived materials.