How do different DMTs affect people’s COVID-19 vaccine response?

Last updated: 3rd June 2021

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Adapted from a UK MS Society article, written by Catherine Godbold. See original article here.

Previous studies have shown COVID-19 vaccines are safe for people with MS who are taking disease modifying therapies (DMTs). But they didn’t tell us how well the vaccines work for people taking different DMTs.

It’s possible that people on some MS treatments might have a reduced response to the vaccines. This could happen because vaccines work by triggering an immune response and DMTs work by dampening down the immune system.

Some DMTs, including cladribine, fingolimod and ocrelizumab, do this more than others. So researchers from Israel studied data from people with MS taking these DMTs to see how their immune systems responded to the Pfizer-BioNtech vaccine.

What did the researchers do?

The researchers studied data from 125 people with MS who had received both doses of the Pfizer-BioNtech vaccine. They compared this group to 46 people without MS.

People with both relapsing and progressive MS were included. 23 people were taking cladribine, 26 had received fingolimod and 44 ocrelizumab. The rest were not taking any DMT.

One month after their second vaccine dose, they all provided blood samples so the researchers could look for the presence of a type of immune cell called an antibody.

Antibodies are produced to fight a specific virus. So higher levels of antibodies following the vaccine could show your immune system is mounting a response to protect you from COVID-19.

What did they find?

The results showed responses to the vaccine were different for people taking different DMTs.

Cladribine All of the people treated with cladribine showed high levels of COVID-19 antibodies. In fact, their antibody levels were similar to people taking no DMT and people without MS.

This suggests if you’re taking cladribine, it shouldn’t affect your response to the Pfizer-BioNtech COVID-19 vaccine.
Fingolimod and ocrelizumab Most people taking fingolimod or ocrelizumab had much lower levels of antibodies. Only 4% of the people on fingolimod and 23% of the people on ocrelizumab had enough antibodies for the researchers to consider the response as protective.

This may suggest people taking fingolimod or ocrelizumab get less protection from the Pfizer-BioNtech vaccine. But although antibody levels give a good indication of the level of protection, they do not tell the whole story.

Antibodies aren’t the only immune cells that can help your immune system fight a virus. And this study hasn’t looked at the response of those other cells, like T and B cells. This is really important. It might be that if you take ocrelizumab or fingolimod, your immune system responds to the vaccine in other ways.

Watch this space

This research only studied small numbers of people taking each DMT, which makes it hard to draw definitive conclusions.

For example, when the researchers looked only at people on ocrelizumab who produced antibodies, they found higher levels of protection if the gap between the most recent dose of ocrelizumab and receiving the vaccine was longer. So this interval might be important, but data from 10 people aren’t enough to know either way.

We also don’t know whether we’d see the same results for the other COVID-19 vaccines currently being used in different countries around the world.

But new studies on COVID-19 and MS are being published all the time, so we should get answers to some of these questions soon.

Global COVID-19 advice for people with MS

The global COVID-19 advice for people with MS continues to be that:

  • All people with MS should be vaccinated against COVID-19
  • People with MS should be vaccinated as soon as the vaccine is available to them
  • Even once you have received the vaccine, it is important to continue to take precautions against COVID-19, such as wearing a face mask, social distancing and washing your hands, because new variants are emerging that may not be protected against by the current vaccines.

The COVID-19 vaccines can be administered to people with MS who are being treated with MS therapies. Continue taking your disease modifying therapy (DMT) unless you are advised by your MS healthcare professional to stop or delay it. Stopping some DMTs abruptly can cause severe worsening of MS.

  • It is safe to receive a COVID-19 vaccine when you are on MS therapies (DMTs)
  • Delaying the start of a DMT, or altering DMT timing, is not a safety issue – it is a strategy to allow the vaccine to be fully effective

For more information on this, view the global COVID-19 advice for people with MS: www.msif.org/covid19.

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