Multiple sclerosis and Covid-19, a dangerous mix? On the eve of World MS Day, specialists are worried about the effects of certain treatments, anti-CD20, after an infection with the coronavirus. “Patients treated with this class of treatments are both more exposed to severe forms of Covid and risk responding less well to vaccination,” explains neurologist Jean Pelletier, from the Arsep Foundation (Help for research on sclerosis in plates).
According to him, “around 20%” of patients with multiple sclerosis (MS) take this type of treatment, either at the onset of their illness or because others have not worked. The two drugs affected are rituximab and ocrelizumab.
A double penalty
Administered “in the form of infusions every six months”, these drugs are “extremely effective in the basic treatment of multiple sclerosis”, according to Professor Pelletier. But from the point of view of the Covid, it is on the other hand the double penalty.
On the one hand, the increased risk of developing severe forms of Covid has been highlighted in recent months by several French, Italian and American studies. On the other hand, more recently, fears have arisen concerning vaccination. “We see people with MS and treated with these anti-CD20 who do not produce antibodies after vaccination against Covid”, according to Professor Pelletier, with therefore the risk of “non-protection”. This is all the more worrying as the effect of these treatments seems “probably much more prolonged” than the six month interval they are taken.
New studies to find out more
At this stage, these observations are above all based on “particular cases”, but studies will allow us to know more. This is particularly the case of a French study headed by Inserm and called COV-POPART. It “aims to assess the effect of vaccination against Covid” in patients treated for several diseases (cancer, kidney disease, diabetes, MS, etc.), depending on the treatments they take.
For multiple sclerosis, chronic disease affecting the central nervous system, 600 patients must participate, and “we will be able to have a first response in 6 months”, hopes Professor Pelletier, according to whom this could make necessary an adaptation of the vaccination strategy in the people concerned.
Other diseases concerned
“This class of anti-CD20 is not specific to multiple sclerosis, but is used in many other autoimmune diseases such as rheumatoid arthritis, psoriasis. So this is a question that goes beyond MS,” he emphasizes. The effects that anti-CD20 seem to cause from the point of view of Covid could be explained by the fact that these drugs act on B lymphocytes, “the cells that make antibodies”, according to the specialist.
On the other hand, there is no similar signal concerning other DMARDs, such as interferons, which could even have a “somewhat protective” effect.