VACCINE RESOURCE COMMITTEE

of the Edmonton Zone Medical Staff Association

View Full List of Vaccine Questions Here

General Vaccine Question #7:  

Are there mercury or other toxic substances in vaccines?

There can be trace amounts of additional ingredients such as adjuvants, preservatives, additives, and other substances in vaccines.

 The Centre for Vaccines, Clinical Trials and Biostatistics (CVCTB) is responsible for the regulatory and scientific evaluation of clinical trials to ensure participant protection, quality (chemistry and manufacturing) evaluation of vaccines and allergenic extracts as well as clinical evaluation of preventative vaccines, infectious disease therapeutics, anti-infective hyper-immune globulins and changes to clinical processes used by establishments in collecting blood and plasma. It also provides biostatistical expertise to support the review of drug submissions for the Directorate.

Adjuvants

Adjuvants, like aluminum salts and squalene, are added to some vaccines to boost the body’s immune response. Without adjuvants, people might need more or higher doses of vaccines to achieve protection.

Aluminum is found in air, food, and water, and it’s also present in breast milk and infant formula in amounts similar to those in vaccines. Once in the bloodstream, aluminum is processed the same, whether injected through vaccines or taken in through food. Hundreds of millions of people have been safely vaccinated with aluminum-containing vaccines.

Squalene is a naturally occurring substance found in plants, animals, and humans, as well as in certain foods and cosmetics. It is made by the liver and circulates throughout the bloodstream.

Preservatives

Some vaccines contain very small amounts of preservatives to prevent harmful germs from growing in them. Examples of these preservatives include phenol, 2-phenoxyethanol, and thimerosal.

Thimerosal is a preservative that contains a form of mercury called ethylmercury, which is different from the type of mercury (methylmercury) found in the environment. Ethylmercury is broken down and removed from the body much faster than methylmercury and is, therefore, much less likely to build up and cause harm. Most routine childhood vaccines in Canada don't contain thimerosal, except for some influenza vaccines. Thimerosal has been used safely in vaccines for many years, and research shows no evidence that it causes harm.

Additives

Additives, such as gelatin, human serum albumin, or bovine-derived reagents, are included in vaccines to keep them effective during storage.

The gelatin used in vaccines is the same substance found in many foods, such as Jello, marshmallows, and gummy bears. Severe allergic reactions to gelatin are extremely rare, occurring in about 1 case per 2 million doses.

Human blood products are not typically found in vaccines, with two exceptions: the rabies vaccines Imovax® Rabies and RabAvert®, which contain albumin derived from human blood. While there is an extremely small theoretical risk of infectious agents being present in human blood products, steps in the manufacturing process of both human albumin and human albumin-containing vaccines eliminate the risk of transmission of these agents. There have been no documented cases of vaccine-related transmission of infectious agents by human serum albumin.

In Canada, some vaccines are made using bovine-derived reagents (materials sourced from cows). These ingredients come from cows known to be free of bovine spongiform encephalopathy, also known as "mad cow disease." The risk that currently licensed vaccines contain prions—the proteins responsible for variant Creutzfeldt-Jakob disease, the human form of mad cow disease—is zero.

Other substances

Some substances from the manufacturing process, suchas formaldehyde, antibiotics, egg proteins, or yeast proteins, may remain in minuscule or negligible amounts in the final product.

Formaldehyde is often used to kill or weaken the virus or bacteria used to make a vaccine and is removed during the manufacturing process. Any trace amounts that may be left in the vaccine are safe. Formaldehyde is naturally produced in the body and helps with metabolism. There is about ten times more formaldehyde in an infant's body at any given time than is found in a vaccine.

Certain materials — such as thimerosal, formaldehyde and aluminum — are used to kill bacteria and make vaccines as safe and effective as possible. The minimal amounts of thimerosal (a mercury-based preservative), formaldehyde and aluminum contained in vaccines are necessary for their safety and effectiveness. These materials occur naturally in the environment, and the amounts contained in vaccines are much lower than children are exposed to on a day-to-day basis.

Clinicians may refer to Table 1 in part 1 of the Canadian Immunization Guide for a table that lists vaccines authorized for use in Canada and their ingredients.

Sources

Government of Canada: Biologic and Radiopharmaceutical Drugs Directorate
Government of Ontario: Why vaccinations are a healthy choice for a strong immune system
Immunize BC: Safety: Vaccine Ingredients
Canadian Immunization Guide: Part 1 – Table 1 – Types and Contents of Vaccines Authorized in Canada