Key CDC Panel Recommends Thimerosal-Free Flu Vaccines for Kids & Adults
A significant recommendation regarding the composition of flu vaccines has emerged from the CDC’s primary advisory body, the Advisory Committee on Immunization Practices (ACIP). At a recent meeting, the committee turned its focus to thimerosal, a mercury-based preservative used in certain vaccine formulations, proposing a shift toward versions without this ingredient for specific populations.
What is Thimerosal and Why is it Used?
Thimerosal is a preservative containing mercury that has been utilized in multi-dose vaccine vials and other medical products since the 1930s. Its main purpose is to prevent the growth of potentially harmful bacteria and fungi that could contaminate the vial after it’s opened and used for multiple doses.
A History of Reducing Mercury in Vaccines
Due to growing public health concerns about potential mercury exposure from various sources, leading health organizations including the American Academy of Pediatrics, Public Health Service agencies, and vaccine manufacturers agreed in the early 2000s to reduce or eliminate thimerosal from vaccines.
By 2001, thimerosal was successfully removed from nearly all vaccines recommended for children aged 6 and younger. However, it remained in some multi-dose formulations of the influenza vaccine.
The New Recommendation: Thimerosal-Free for Key Groups
Fast forward to the recent June 27th ACIP meeting. The committee voted on proposed recommendations specifically concerning thimerosal-containing influenza vaccines.
The outcome was a formal recommendation that all adults (including pregnant women) and all children 18 years and younger should receive seasonal influenza vaccines only in single-dose formulations. Single-dose vials do not require a preservative like thimerosal because they are designed for one-time use, minimizing the risk of contamination after opening.
While multi-dose flu vaccine vials containing thimerosal are still available, thimerosal-free single-dose options are also currently in use. The ACIP’s recommendation effectively guides healthcare providers toward prioritizing these thimerosal-free versions for the specified age groups and pregnant individuals.
Balancing Safety Claims and Policy Shifts
Despite the recommendation to move toward thimerosal-free options for these populations, it’s important to note that the CDC and other health agencies continue to maintain that thimerosal, at the low doses used in vaccines, is safe. The CDC website explicitly states that thimerosal use in medical products has a strong safety record and that data from many studies show no evidence of harm caused by the low doses present in vaccines.
Dr. Jacob Glanville, CEO of biotechnology company Centivax, commented on the situation, noting that thimerosal has largely been out of routine childhood vaccines in the U.S. for over two decades. He observed its continued presence primarily in some multi-use vials, often used outside the U.S., and voiced support for any effort to remove it entirely, stating that other effective non-mercury preservatives exist.
This recommendation marks a significant step in vaccine administration policy for specific populations, further aligning flu vaccine practices with those already established for most other childhood immunizations, while public health agencies continue to affirm the ingredient’s safety profile at current usage levels.
