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New insights into risk of MS in people living with HIV

Wednesday 17 January 2024

Dr. Sophie Quick

A study of health information from people who are living with HIV and taking antiviral treatments showed they had a reduced risk of developing MS.

There’s evidence that viruses are one environmental factor which could play an important role in MS. But we don’t fully understand this link.

New research shows people who used antiviral treatments for human immunodeficiency virus (HIV) also had a reduced risk of developing MS. 

What did they find?

The team looked at 10 years' worth of health information from over 29,000 people with HIV from Canada and Sweden. They found only 14 of these HIV-positive people developed MS. This is 45% fewer cases than would be expected for a group of this size.

These results don’t mean being HIV-positive will protect against developing MS. Nearly everyone in this study took antiviral drugs as a treatment for HIV. So, the researchers couldn’t tell whether it was the virus or the antiviral therapy which reduced the risk of MS. More research is needed to understand this better.

Read more about viruses and MS

Why might this happen?

This study shows there’s a link, but we don’t know why this might happen. The researchers suggested two possible explanations.

  • Infection with HIV might reduce the risk of MS. The virus infects the same type of immune cells which mistakenly attack myelin in MS. So if there are fewer of these cells, this might reduce the likelihood that they start to damage myelin. But these immune cells are needed for other essential roles in the immune system.
  • The antiviral drugs might reduce the risk of MS. These drugs suppress viruses of all kinds. Including viruses associated with MS, like Epstein-Barr virus. So, the antiviral drugs could prevent a virus from playing a role in someone developing MS. But there are many factors which influence whether this happens.

We need more research to figure out which theory is true. And if antiviral drugs as used in HIV may also be a good treatment approach for MS.

What does this mean for people with MS?

This research gives us new evidence for the link between viruses and the risk of developing MS. It could suggest new ideas for treatments.

Future research could investigate whether antiviral drugs like those used to treat HIV could slow MS disease progression. Repurposing drugs for new treatments means they can reach the people who need them faster.

Read more about repurposing drugs for MS 

How do antiviral drugs work?

Antiviral drugs can help the immune system fight back and can mean less severe symptoms. They lower the amount of virus in the body by helping to stop the virus from multiplying.

Caitlin Astbury, our Research Communications Manager, says: “We don’t know for sure why people develop MS, but research suggests there is no one thing on its own that will cause it. It’s likely triggered by a mix of genetics, and environmental and lifestyle factors. This research adds to the evidence that viruses may play a key role in causing MS.

“More than 130,000 people live with MS in the UK, and we still have so much to learn about the condition and how we can stop it developing. We’re funding world-leading research, including into the causes of MS, so ultimately fewer people will go onto develop MS in the future.”

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