I had never heard about preservative-free vaccinations till recently, had you? We just went to the clinic and got the vaccinations done, no questions asked. You might call this blind belief on our part, but I prefer to call it trust. For me, the pediatrician’s word is more trustworthy than Google. 

So recently when we were in her clinic for the annual flu vaccinations, the waiting area is where I read about preservatives in vaccines and the alternatives. The first thought that came to me was “We avoid food that has preservatives in it but are giving vaccines with preservatives? Is that normal?”

Intrigued, I asked my pediatrician about this and she shared some useful information with me

Why do vaccines need preservatives?

Preservatives in vaccines help inhibit the growth of bacterial and fungal contamination which may be caused in multi-dose vials. As multi-dose vials need less storage space and in-turn cause less wastage, they are used in many countries around the world. The preservatives, however, are needed only for multi-dose presentations. 

What is the kind of preservatives used in vaccinations?

Thiomersal is a compound containing ethyl mercury which is used to prevent bacterial and fungal growth in inactivated vaccines (vaccine in which virus has been killed). It is used in multi-dose vials of flu vaccine. 

In 1998, a doctor published a small study claiming that MMR vaccine caused children to develop autism. While the study was extremely flawed, it set off a chain of misinterpretation (all this before the What’s App forward era). This led to parents abandoning vaccinations altogether. To avoid unwarranted public fear, the use of thiomersal has been limited to multi-dose vaccines. 

preservative-free vaccinations

Which Vaccines contain Thiomersal?

Vaccines that contain thiomersal include- vaccines for DTP ( Diphtheria, tetanus, and pertussis), Hepatitis B, rabies, influenza, and meningococcal diseases. WHO has regularly monitored scientific evidence relating to the use of thiomersal. While there is no evidence to prove any adverse effects due to using of thiomersal, the vaccination manufacturers mention the amount of thiomersal in the vaccinations nonetheless, as a safety measure.

What is the alternative?

Thiomersal-free or preservative-free flu vaccinations are an alternative to this. Preservative-free vaccines are single-dose vials, unlike the others that are available in multi-dose vials. A single-dose vial as the name suggests are vials that have formulation for a single person or child. With new research, reformulation and new product development in the form of single-dose vials thiomersal use have been on the decline.

According to the Centers for Disease Control and Prevention, approximately 85% of projected vaccine supply produced for the 2019-2020 flu season will be thimerosal-free (i.e., preservative-free).

Armed with this knowledge, I found myself in a better position to decide for my children. While the preservative in itself might not be harmful, today’s vaccinations being preservative-free helps me reassure myself and even educate other parents about such vaccinations. 

I have referred to some well- known scientific websites to reconfirm my understanding of the topic and have added the links below as reference. Have you read up or know more about preservative-free vaccinations? Do share about it in comments below. Would love to know more about it. After all, well-informed parents make better decisions and take better care of their children, isn’t it?

What’s #YourCareQuotient? How much do you understand your child when it comes to sleep patterns, feeding and vaccination? Take the easy, interactive quiz that guides you and get the childcare guide now. 


  1. https://www.who.int/immunization/newsroom/thiomersal_questions_and_answers/en/
  2. https://www.verywellhealth.com/preservative-free-flu-vaccine-770551
  3. https://www.fda.gov/vaccines-blood-biologics/safety-availability-biologics/thimerosal-and-vaccines#othr 

Disclaimer – The views expressed in the blog content are independent and unbiased views of solely the blogger. This is a part of the public awareness initiative supported by Sanofi Pasteur India. Sanofi Pasteur bears no responsibility for the content of the blog. One should consult their healthcare provider for any health-related information.

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25 Replies to “How are preservative-free vaccines different from the other options?”

  1. I have given my kids the regular vaccines for 3 years is it differ from this regular vaccine which we get from pediatrician

  2. I agree with you Neha as parents we should research well the options at hand, I did not know about preservatives free vaccines and happy to read your post

  3. Honestly, I was absolutely unaware that there are preservatives in vaccine or there can be one without preservatives too. Will share your blog with all new parents I know.

  4. Yeah never thought of such a thing while vaccinating my son. Preservative free vaccines are totally new for me. So thanks for sharing it. Will be sharing it with other friends whose children will be taking vaccinations.

  5. I got to know about preservative-free vaccines from a friend a few months ago. Now we too have decided to get preservative-free vaccines only, why not when we have an option. Thanks for sharing your experience, I am sure this information will be helpful for many parents.

  6. Honestly, I didnt know about this thing that there is a preservative in vaccines but now I will make a conscious decision for further vaccines.

  7. When msgs about vaccinations tanking start doing the rounds of whatsapp parents freak out. I remember this happening during Polio dosage. But this bit of information clarifies and reassures me..

  8. Yeah. During vaccination of my son we also never had enquired about preservative free vaccines. As such had never known about that. So thanks for sharing it. Will Lso forward this to friends whose children will be taking vaccination. Thanks for sharing.

  9. This is such a detailed information about vaccination. I am passing this to my sister who is a new mom.

  10. The preservative free vaccination is best in some vaccines to keep them from becoming contaminated. This vaccination helps to remove harmful vaccine side effects.

  11. Indeed vaccine becomes the need of today and every parent should know about the preservative free vaccine.

  12. I didnt know we have preservative free vaccines too. I will surely pass this information to NY close ones who have small babies.

  13. I didn’t know that vaccines have preservatives… This post was really helpful for me and I am sure parents will benefit from this!

  14. To be honest, I did not give a thought to this at all when got my kids vaccinated. But when their next vaccine is due I am going to check this. Thanks for sharing.

  15. There’s no such vaccines exist I thought. This post is really insightful and helpful for the parents like us.

  16. I had no idea that vaccines have preservatives. Thank you for sharing this information, I will keep this in mind when I will have my own kid and will share it with other parents too.

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