In the fourth and last part of this series, finally, I want to talk about the much-discussed possible harms of vaccines. I hope to dispel one or other prejudice against vaccines.

Are additives in the vaccines safe?
In addition to the pathogen the vaccines contain other additives and preservatives. These applies to all other drugs as well. Their compatibility is checked very carefully before approval of the vaccine. The most commonly discussed additive is mercury (thiomersal). Thiomersal has been used in vaccines as a preservative to prevent fungal and bacterial contamination. Thiomersal contains mercury. Mercury is regarded as nephro-(kidney) and neuro-(nerves)toxic, but only in much higher doses than those found in vaccines. Clinical studies did not show any association between the presence of thiomersal in vaccines and neurodegenerative damage. However, thiomersal has been removed from all pediatric vaccines in almost all European countries. So, there is no more reason to worry about it. Aluminium is used as an adjunct in inactivated vaccines. It serves to increase the effects of the vaccines. Without it an effective vaccination with inactivated vaccines is not possible. Their quantity in the vaccines is well below the threshold prescribed in Europe.

Vaccinations and multiple sclerosis
There have been repeated concerns that vaccination, especially against hepatitis B, may cause or promote the progression of multiple sclerosis. In the studies conducted, no association between vaccination and multiple sclerosis has been shown.

Vaccination and autism
Probably the most widespread and unsetting misinformation. Caused by a study with a dubious methodology published in 1998, which allegedly demonstrated an association between measles vaccination and gastrointestinal disorders and development disorders in 12 children. In 2004, an American journalist published references to a conflict of interest of the author, whereupon 13 of the co-authors distanced themselves from the article. Finally, in 2011, the article was completely withdrawn by the journal (source: Paul-Ehrlich-Institut). In a meta-analysis of the Cochrane library (database of scientific publications), no association between vaccination and autism or Crohn’s disease (an inflammatory bowel disease) could be confirmed.

Vaccination and diabetes mellitus type 1
In recent decades, a possible link between the development of type 1 diabetes mellitus (predominantly in young age due to insulin deficiency) and vaccination in childhood has been discussed. Such an association cannot be confirmed in any scientific study. In 2000 there was conducted one of the biggest study about this argument. Interestingly, this study found a potentially increased risk of developing type 1 diabetes mellitus for children with very early and perinatal (at birth) infections.

Vaccination and allergy
An allergy is an overreaction of the immune system to basically harmless substances. Many patients are afraid that vaccinations can lead to the development of allergies or exacerbate existing allergies. Studies have shown that there is no connection between vaccinations and the development of allergies. It even seems to be the opposite. In countries where there has been a duty to vaccinate, such as the former GDR, there were fewer allergies. In some cases of allergies or atopic dermatitis, there is an improvement from the vaccinations. Caution is advised only if an allergy to any of the components of the vaccine is known. Then, the risk and benefit must be discussed with the physician.