New insights into impact of immune-suppressing 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 a new study led by Cardiff University.

Disease-modifying therapies (DMTs) are a group of treatments that suppress the body’s immune system and are used by people with MS and other conditions such as cancer and rheumatoid disease. 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.

This new study, led by Cardiff University and Queen Mary University of London (QMUL), and involving sample collection at five sites across the UK, is published in the journal Annals of Neurology , provides the largest peer-reviewed evidence of the effect of MS 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 and vaccination.

Dr Emma Tallantyre, Clinical Senior Lecturer in Neurology at Cardiff University, said: "Questions about the COVID-19 vaccine are among the most common we are currently facing from people with MS in our clinics.

"Highlighting groups who have mounted an inadequate 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."

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.

They found people with MS taking either of two particular DMTs, fingolimod and ocrelizumab, were less likely to produce antibodies in response to AstraZeneca and Pfizer 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 vaccine response.

Jo Welton, 38, was diagnosed with relapsing MS in 2009 and lives with daily fatigue, weakness and pain in her left leg. She has been on the DMT Gilenya for nearly eight years and joined the study after being told about it by her MS team. Since then, 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 has worked,

Jo, a medical writer from South Wales, said: "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. 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."

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% of this group were able to produce a strong T-cell response, despite having a poor antibody response.

Dr Ruth Dobson, Clinical Senior Lecturer in Neurology at QMUL, said:"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."