Treatments used to help people with multiple sclerosis (MS) manage their condition can reduce the effectiveness of COVID-19 vaccines, a new study has found.
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 provides the largest peer-reviewed, published evidence of the effect of DMTs on immune responses to COVID-19 vaccines.
Researchers, from Cardiff University and Queen Mary University of London, said they hoped the new insight 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.”
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 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 the 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, adds: “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.”