First of all, I would like to wish all readers of DocBlog a happy and healthy New Year 2022!
The new year is only a few days old and once again a virus is affecting the MS community: But – you can hardly believe it – it’s not the coronavirus, but an old acquaintance, namely the Epstein-Barr virus (EBV), a DNA virus from the group of herpesviruses, which is ubiquitously transmitted mainly through droplet infection.
This virus, which in childhood usually leads to symptomless infections, but in adolescents often leads to the very unpleasant and severe infectious mononucleosis (Pfeiffer’s glandular fever, “Kissing Disease”), has been known for many years as a risk factor for multiple sclerosis. In particular, with manifest infectious mononucleosis, the risk of MS is up to 20 times higher.
A study by US researchers was published in the prestigious scientific journal Science at the beginning of 2022, examining a total of 10 million American military personnel in a longitudinal study. The authors were able to show that the risk of MS after an EBV infection was about 32 times higher – such a connection could not be found for any other viral infection. From these data, the authors conclude that the Epstein-Barr virus is the main cause of multiple sclerosis (Bjornevik K et al. Longitudinal analysis reveals high prevalence of Epstein-Barr virus associated with multiple sclerosis. Science. 2022 Jan 21. doi: 10.1126/science.abj8222).
EB virus: one or the cause of MS?
The identification of a cause is of outstanding importance for the treatment of diseases – that’s why this study has attracted a lot of attention in the general press. However, for several reasons, which I will outline shortly, I do not share this enthusiasm – and I am not sure whether the Epstein-Barr virus has really identified the cause of multiple sclerosis.
We must bear in mind that more than 90% of people worldwide (some literature even speaks of 98% of people) are infected with EBV. If EBV represents such an outstanding cause for MS, the question is why so few people (in proportion) actually develop MS. This suggests that other factors besides the EBV infection must contribute to the development of MS. Therefore, the study impressively proves that EBV plays a role in the development of MS – the much more crucial question, which the study cannot answer, and which is much more important for the people currently suffering from MS, namely, what mechanisms play a role in the development of MS by EBV, the study cannot answer.
Vaccination against Epstein-Barr desirable for several reasons
Nevertheless, in light of the data, the question arises as to what would happen if one could prevent infection with EBV through vaccination. This is a truly fascinating question. The problem, however, is that to this day no vaccine exists against EBV that reliably prevents infection (i.e., guarantees sterile immunity, which we would need to fight MS). Furthermore, one needs a very long breath: If one had a vaccination, one would have to start immunizing children, but then one would have to wait at least 20 years to gain insights into whether the frequency of the disease decreases.
However, it definitely makes sense to consider a vaccination against EBV. Even though most infections occur early in life and are harmless, preventing infectious mononucleosis in adolescents would be a primary goal of vaccination. On the other hand, it is known that EBV is also involved in the development of certain tumors, including cancers of the blood-forming system. A vaccine would also be valuable for the prophylaxis of these diseases. Thus, in addition to the theoretical prevention of MS, there are other clear goals that justify vaccine development against EBV. However, such a development, unlike with Corona, where there was a worldwide vital interest in vaccine development, is likely to take several years. The development of mRNA vaccines in the Corona pandemic gives hope that this could also be a key technology for the development of EBV vaccines.
In any case, the current study has shed clear light on the role of EBV infection in the development of multiple sclerosis, and it will be exciting to see what developments result from this in the near future. It is scientifically a very exciting topic – however, I doubt whether this knowledge is relevant for people who are currently affected by MS.
