Does the Vaccines really Contain Harmful Mercury?

Does the Vaccines really Contain Harmful Mercury?

In the past few years, I had to face many persons questioning the safety of vaccines. The vast majority of them are concerned about the mercury content in vaccines.

Why use Thiomersal in vaccines? Isn’t it a mercury containing harmful compound? Then why are the vaccines containing mercury being given to small children and adults all over the world?

These are the leading questions that I get from the parents who are against the idea of vaccination. There have been many instances where “mercury poisoning” using vaccines was falsely propagated. The emergence of WhatsApp has made it easy for these anti-vaccinators to spread their false message easier than ever before.

So today morning when I heard such an audio clip, I decided to write an article explaining why vaccines are still safe and not poisonous for humans!

What is Thiomersal?

Thiomersal, (also known as Thimerosal) is a chemical compound used in vaccines to prevent the growth of bacterias and fungi during their storage. It is also used in vaccine production in order to inactivate certain toxins and micro-organisms, thus maintaining a sterile environment. This is very important because the micro-organisms and toxins if present in vaccines can be very dangerous and can even lead to death.

The chemical name of Thiomersal is “sodium 2-ethyl mercurio thio-benzoate”. As is evident from the chemical name, this compound does contain mercury in it. But, is it really harmful to the children and adults who get their routine vaccine shots?

Thiomersal has been widely used in the medical industry since 1930s. Apart from vaccines, it is also used as preservatives in immunoglobulin preparations, antivenins, ophthalmic and nasal products and even in tattoo inks.

Which Vaccines contain Thiomersal?

Not all vaccines used in the Universal Immunization Programme contain thiomersal. It is more commonly used in mixed dose vaccines. Live and single dose vaccines do not necessarily need agents like thiomersal. The table below will help you easily identify the vaccines which contains this preservative.

Vaccines containing ThiomersalVaccines that DO NOT contain Thiomersal
DTaPOral and Injectable Polio
HibYellow fever
Hepatitis BHepatitis A
Pentavalent = DPT + Hib + Hepatitis BJapanese Encephalitis
InfluenzaVaricella (Chicken Pox)

Read : The importance of vaccines

How is Thiomersal different from Mercury?

One must understand that there are different forms of mercury in the environment. Some are toxic, while others are not.

As already explained, thiomersal contains “ethyl” mercury and not “methyl” mercury. The main difference between these two compounds is that, while methyl mercury gets accumulated in our body causing several toxic effects, ethyl mercury doesn’t. This different type of mercury in thiomersal has the ability to be metabolised at a faster rate and they get excreted quickly from our body. Thus thiomersal is less likely to produce harmful effects on the human body.

Are these Vaccines safe?

Yes. You should read the following lines very carefully. These lines were taken from the official World Health Organization website.

Upon review of the current epidemiologic evidence and phamacokinetic profile of thiomersal, the Global Advisory Committee on Vaccine Safety concluded that there is currently no evidence of mercury toxicity in infants, children, or adults exposed to thiomersal in vaccines. It also concluded that there is no reason to change current immunization practices with thiomersal-containing vaccines on the grounds of safety

Thiomersal doesn’t cause autism in children. Researches have not found any kind of connection between thiomersal and autism in the past 85 years.

The difference in the chemical structure of thiomersal and methyl mercury has already been discussed. Considering these facts, it is more than confirmatory that, thiomersal is safe!

Why some countries stopped using Thiomersal in Vaccines?

The USA and some countries have decreased the use of thiomersal in vaccines only as a precaution. But even in those countries, it’s use has not been discontinued altogether. It is still being used in inactivated influenza vaccines and in vaccines like DT and TT which are not routinely given for children.

In developing countries like India,  multi dose vaccines are still being used at large. Thsese countries cannot afford to make single dose vaccines and not to use preservatives like thiomersal. The cost of producing single dose vaccines and the need to refrigerate them for proper storage and transport makes the use of thiomersal absolutely necessary.

Final words

Even though thiomersal is a mercury containing compound, it is safe to use in vaccines. It has been in use for several years now and no evidence of harmful effects have been discovered yet. There are thousands of anti-vaccine ideologists who have been using” thiomersal” and “mercury poisoning” as their main weapon for propagating base-less ideas.

The decision is yours. Who would you rather believe? A person whose biggest skill is to make audio and video clips against vaccines and circulating it through the social media networks or an authority organization like the World Health Organization? We at BeingTheDoctor hope that you don’t fall in the traps of these dangerous egoists.

The discovery of vaccine is considered as a revolutionary milestone in medical industry. They have saved millions of lives already and are here to stay.


Image Credit – NIH

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