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Vaccines and Autoimmune Diseases: Should We Fear a Link Between Them?

Authored by Anna Hayek

Art by Michelle Choi

The combined efforts of international organizations and major institutes over the past 10 years have brought routine immunization coverage to very high levels. This considerable input saves millions of lives a year. In this particularly favorable context, it is paradoxical that in many industrialized countries, the attention of the public is focused on the potential risks of vaccination rather than on the benefits that can be derived from it. Indeed, vaccinations have always been the subject of controversy with doubt about the vaccines' secondary effects. But what could be the dangers resulting from these secondary effects? Could these undesirable effects cause diseases, and to what extent? We will first get a deeper insight into how vaccines work to draw later on the causal link between the latter and the rise of auto-immune diseases.

First, let us familiarize ourselves with what a vaccine is. A vaccine is a pathogenic substance that, when inoculated into an individual, will confer immunity against certain illnesses. By stimulating the immune system, vaccines trigger the immune system and obtain a specific response from the organism against an antigen, either viral, bacterial, cellular, or even molecular. The vaccination principle lies in the following process: following an injection, a detection of the antigen is produced through a macrophage and later by their migration towards the lymph nodes. Then, the production of antibodies and the activation of the lymphocyte T take place. At the same time, the storage of the memory cells from or through which the organism will become immune. Finally, in the case of infection, the action of the lymphocyte T will allow the elimination of the infected cells. 

As we hear these days after the COVID-19 pandemic, numerous people fear the vaccine composition. But what exactly is their main concern? Vaccines are principally composed of an active component: the antigen (strange body of protein nature, attenuated virus, genetic information ARN-ADN, etc.), preservatives, stabilizers, etc., but mainly of adjuvants or additives. These adjuvant components, added to the vaccine antigen since 1920, allow a simulation of innate immunity, an essential prerequisite for a strong adaptive immune response that is quite specific and primary. Although this composition seems like a simple mixture of elements, setting up vaccines remains a challenging process in modern times. Several stages should be taken into consideration to obtain a product that offers the best level of protection for the greatest number of people. Thus, the setup of the vaccines and their commercialization in the markets are necessary steps to evaluate their short-term and long-term security and efficiency [1]. 

Despite the efforts and considerations of vaccine making, undesirable effects can always be levied, and these might have more or less serious consequences, including vaccination error, the vaccine quality, or even a vaccine product. This being said, the reactions linked to the vaccination product might have effects that are more or less serious for the vaccination. These reactions may be equally the origins of autoimmune illnesses and diseases [2]. An autoimmune disease is a pathology in which the immune system attacks its constituents. Autoimmune illnesses/diseases have genetic determinants; however, they are equally subject to environmental factors and conditions. Some antigens by molecular mimicry could induce auto-reactive lymphocytes originally through an autoimmune phenomenon. Some controversies have touched on the vaccines (HPV vaccines, meningococcal C conjugate vaccine) or their components (thiomersal, mercury, aluminum) and are currently focusing on the vaccines' putatives responsibly and particularly on their adjuvants in the occurrence of autoimmune diseases.

This idea is illustrated in the very recent crises of narcolepsy with catalepsy and the flu vaccination pandemic H1V1 with Pandemrix H1N1 [3] . The narcolepsy sleep disorder is an auto-immune disease characterized by brutal and uncontrollable bouts of sleep. It can be attributed to a sudden loss of muscle tone, called cataplexy. The closest hypothesis is that certain proteins of the virus share a homologous sequence with the proteins expressed in the hypocretin neurons [4] . A vaccination activates a specific lymphocytic population of a given antigen, which migrates in the brain via the hematologist's encephalitic barrier, recognizing and later destructing the neurons, causing difficulties in staying awake [5] .

In conclusion, the relationship between vaccines and autoimmune diseases is a complex and extensively studied area in the fields of immunology and epidemiology. While vaccines have been associated with certain autoimmune conditions in rare instances, it's important to emphasize that the overall risk of developing narcolepsy after vaccination is still relatively low, and the benefits of vaccination in preventing influenza far outweigh the potential risks. While there may be rare instances where vaccines are associated with autoimmune diseases, the overall consensus among healthcare professionals and experts in immunization is that the benefits of vaccination in preventing deadly infectious diseases far outweigh the minimal risks.


Works Cited

[1] Guo, M., Liu, X., Chen, X., & Li, Q. (2023). Insights into new-onset autoimmune diseases after COVID-19 vaccination. Autoimmunity reviews, 22(7), 103340. 

[2] Toussirot, É., & Bereau, M. (2015). Vaccination and Induction of Autoimmune Diseases. Inflammation & allergy drug targets, 14(2), 94–98. 

[3] Centers for Disease Control and Prevention. (2022). Narcolepsy Following 2009 Pandemrix Influenza Vaccination in Europe. CDC.

[4]  Buonocore, S. M., & van der Most, R. G. (2022). Narcolepsy and H1N1 influenza immunology a decade later: What have we learned?. Frontiers in immunology, 13, 902840. 

[6] Brown C. (2015). H1N1 vaccine and narcolepsy link discovered. CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne, 187(12), E371. 

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