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New insights into impact of multiple sclerosis treatments on Covid-19 vaccine effectiveness

Treatments used to help people with multiple sclerosis (MS) manage their condition can reduce the effectiveness of Covid-19 vaccines, according to research from Cardiff University and Queen Mary University of London 

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Woman holds Covid-19 vaccine in hands. Credit: scaliger/
Woman holds Covid-19 vaccine in hands. Credit: scaliger/

Disease-modifying therapies (DMTs) are a group of treatments for people with MS and affect the immune system. As vaccines work by triggering the body to produce an immune response, it was suspected that some DMTs could reduce the effectiveness of Covid-19 vaccines.

The study, published in the journal Annals of Neurology, provides the largest peer-reviewed, published evidence of the effect of DMTs on immune responses to Covid-19 vaccines. It is hoped this new information will better equip clinicians to provide guidance to people with MS on treatment options.  

“People with MS have faced uncertainty during the Covid-19 pandemic as a direct result of their condition and the treatments they take to manage it,” says Dr Ruth Dobson, Clinical Senior Lecturer in Neurology at Queen Mary.

“Our study provides high-quality evidence that will support clinicians to advise people with MS on treatment options considering the Covid-19 pandemic. However, further trials are essential to help us understand how best to balance the risks of potentially suspending or delaying MS treatment with the need to effectively vaccinate people with MS against Covid-19.”

Studying immune responses

The research team studied almost 500 people with MS and used a technique known as dried blood spot sampling to investigate the effects of DMTs on Covid-19 vaccine effectiveness. This approach reduced study costs as well as the need for potentially vulnerable patients to attend the clinic during the pandemic.

The findings show that people with MS taking either of two particular DMTs, fingolimod and ocrelizumab, were less likely to produce antibodies in response to AstraZeneca and Pfizer Covid-19 vaccines than people with MS not taking any DMT. If they did produce antibodies, the levels were lower than those found in people taking other DMTs, or not taking any DMT at all.  However, the researchers found that other DMTs, including some that are highly effective for MS treatment, had no detrimental effect on Covid-19 vaccine response. 

Immune cells, such as T-cells, are also an important part of our immune response to vaccines or viruses. The researchers studied T-cell responses in a small group of study participants who failed to mount an adequate antibody response to Covid-19 vaccination. They found that overall, 40 per cent of this group were able to produce a strong T-cell response, despite having a poor antibody response.

Dr Emma Tallantyre, Clinical Senior Lecturer in Neurology at Cardiff University, says: “Questions about the Covid vaccine are among the most common we are currently facing from people with MS in our clinics. Highlighting groups who have mounted an inadequate Covid vaccine response has already been helpful in guiding who should receive additional doses of the vaccine, and who may need to continue to take additional infection-prevention precautions over the winter. We hope further work will allow us to individualise our management, to protect people with MS from Covid, while keeping their MS under control.”

Dr Clare Walton, Head of Research at the MS Society, says: “While this doesn’t mean these patients are necessarily at higher risk of severe illness if they catch COVID-19, it will be worrying for some. It’s vital that people with weakened immune systems are better supported to protect themselves from the virus, including a right to work from home and feeling assured that the general public are doing everything they can to help keep them safe. We also advise people with MS on these DMTs not to alter their treatment without speaking to someone from their MS healthcare team.”

Experiences of people with MS

Jo Welton, a medical writer from South Wales, was diagnosed with relapsing MS in 2009. Day-to-day Jo mainly experiences fatigue, weakness and pain in her left leg. She has been on disease modifying treatment (DMT) Gilenya for nearly eight years. She joined the study after being told about it by her MS team. Since, despite having two AstraZeneca vaccinations she has been told she has reduced immunity to COVID-19 and is waiting to find out if her booster vaccination has worked.

Jo says: “I have a scientific background so was interested in the study as soon as I heard about it. It was also important for me to know how much immunity I had as this impacts my day-to-day living. I’ve followed the guidelines about DMTs and MS right from the start, so this has meant I’ve been shielding for over 20 months. It’s been so difficult seeing everyone getting back to some sort of normality and not feeling like I was able to. I feel vulnerable and, although it’s not deliberate, left behind.

“Ignorance is bliss for some people, but it’s not a risk I want to take. I lost my Grandma to the virus earlier this year – this has made it even more important for me to take the necessary steps to mitigate the risk. Knowing I don’t have immunity means I can continue working remotely, socially distance, and ask friends and family to get their booster vaccine and do lateral flow tests when we meet. Having MS is hard enough without getting COVID-19 as well.”

Support from the wider community

The study was in part supported by a crowdfunding campaign led by Queen Mary Professor Gavin Giovannoni, one of the authors of the paper. Following an accident in November last year, Professor Giovannoni was left with several severe injuries including a mild head injury, fractured pelvis, and cervical spine. To help raise money for this vital research, Professor Giovannoni ran a virtual New York Marathon, in London, and then undertook a sponsored 5km walk whilst recovering from his injuries. 

Professor Gavin Giovannoni, Professor of Neurology at Queen Mary, says: “When the Covid-19 pandemic made it difficult to get funding for this vital research the wider MS community stepped up and made this happen via crowdfunding. Thank you! I am so happy to be alive and well after my accident and to have played a small part in making this study happen.”

More information


For media information, contact:

Sophie McLachlan
Faculty Communications Manager (Science and Engineering)
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