When we become parents, we have another life to care for and nurture. In my case, I had twins so I was doubly happy, doubly responsible and sometimes, doubly anxious too. Vaccinations were the first thing that troubled me. While I followed the immunization schedule religiously, sometimes friends or relatives would pop a question that made me think I was ill equipped to handle little babies.
That phase is over and now I am a sounding board for my sister-in-law who is a new mother. Being older and considered more experienced, she asks me everything from little decisions on buying the right toys to bigger ones like going in for preservative-free vaccines.
So, I did some research, checked with the doctor some more and had a lot of information to handle every query and bust every myth, especially around preservative-free vaccines. Here it is, for you all, when you are in doubt.
Why do vaccines need preservatives?
When we use preservatives in vaccines, they inhibit the growth of bacterial and fungal contaminants that could be introduced during repeated use of a multi-dose vial. Many countries across the world use multi-dose vials because they require less storage space in the cold chain. It also leads to less wastage; both factors have a significant impact on the program costs.
While researching on why vaccines need preservatives; I realised that preservatives are typically needed only for multi-dose presentations. Manufacturers make bulk formulations for the vaccines, so whether it is a multi-dose or a single dose presentation, the vaccine would contain the same preservative. In many countries, for inactivated vaccines supplied in multi-dose vials, the presence of a preservative is a regulatory requirement. (Source: https://www.who.int/immunization/newsroom/thiomersal_questions_and_answers/en/)
What preservative is used in the vaccines?
Thiomersal is a compound containing ethyl mercury that is used in vaccines to prevent bacterial and fungal growth in inactivated (in which the virus has been killed) vaccines presented in multi-dose vials.
Thiomersal is also used during vaccine production; in order to inactivate certain organisms and toxins and to help maintain a sterile production line. It has been used since the 1930s to manufacture vaccines as well as other medicinal products. The manufacture of thiomersal is a very minor component.
Vaccines that contain thiomersal include those against diphtheria, tetanus and pertussis (DTP), Hepatitis B, Haemophilus influenza type b (Hib), rabies, influenza and meningococcal diseases.
Which vaccines do not contain thiomersal?
There are also live vaccines available in the market like the oral polio drops, and the vaccines for yellow fever, measles, mumps and rubella. These do not contain thiomersal. The reason why thiomersal is not used in these vaccines is because it would kill the immunizing component. Let me give you an example; when you talk about inactivated vaccines, with single dose presentations available from a particular manufacturer, there is no thiomersal component in sufficient concentration required to prevent contamination of a vial because those presentations are not meant to be reused.
Does the amount of thiomersal in vaccines pose a health risk?
Since its inception, WHO has closely monitored scientific evidence relating to the use of thiomersal as a vaccine preservative for over 10 years. This has been done by its independent expert advisory group, the Global Advisory Committee on Vaccine Safety.
With the recent brouhaha over vaccinations leading to autism, the WHO Committee have always reached the same conclusion: there is no evidence to suggest that the amount of thiomersal used in vaccines poses a health risk. Other expert groups (the U.S. Institute of Medicine, the American Academy of Pediatrics, the United Kingdom Committee on Safety of Medicines, and the European Agency for the Evaluation of Medicinal Products), have reached similar conclusions.
Even then, as a parent, if you are worried about preservatives in vaccines, talk to your child’s pediatrician about preservative-free vaccines. After all, the safety and comfort of children is paramount for a parent. I hope you have your answer to “Why do vaccines need preservatives?”
So, there you go, as a parent, I did my bit to learn and share more about the safety around preservative- free vaccines. 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.