We know people with MS taking certain disease modifying therapies (DMTs) are less likely to develop an immune response to the COVID-19 vaccine. But we don’t know how much this affects your protection from getting COVID-19 or severe symptoms. A study published last week has taken us closer to some of these answers.
Research has shown that certain DMTs affect the way your immune system responds to COVID-19 vaccines. Some people on fingolimod and ocrelizumab don’t develop the same immune response as people not taking these DMTs.
A new study has looked at whether this might have had an impact on the number of people taking these DMTs testing positive for COVID-19. But we need more data to know for sure.
Comparing infection rates before and after the vaccine rollout
The researchers looked at 3,524 people taking MS DMTs who tested positive for COVID-19 between March 2020 and August 2021. They compared this with the number of people in the whole of England who tested positive during that time. The time period covered before and after the vaccine rollout.
They tracked the rates of infection for people taking each DMT compared to the general population. For most DMTs you saw the same pattern before and after the vaccine roll-out.
But for fingolimod and ocrelizumab there was a change after the vaccine rollout - the difference (higher infection rates) from the general population had grown bigger.
What was the reason for these findings?
The researchers suggest the change could be to do with a reduced immune response to the vaccine.
But it’s important to know these data alone don’t directly tell us how effective the vaccine is at stopping people taking ocrelizumab or fingolimod from catching COVID-19.
The change after the vaccine roll-out could have been for other reasons. For example, perhaps lots of people taking these DMTs chose not to get their COVID-19 jabs.
We do know most people with MS were keen to get the vaccine. So the researchers think their results are likely to be because people taking these DMTs haven’t produced a strong enough vaccine response to stop them catching COVID-19.
We need more detail about these people to say for sure whether people taking fingolimod or ocrelizumab are at greater risk of catching COVID-19 because of a reduced vaccine response. Future studies will need to include data on who was vaccinated and what their antibody levels were.
Our medical advisers say people on these two treatments should be extra careful to follow precautions, even if they’re fully vaccinated and have had a booster. You should be even more careful if you have other risk factors too.
We need research on how ill people are getting from COVID-19
Crucially, this study only looked at whether or not people had a positive PCR test, not how severe their symptoms were.
The researchers want to find out what a reduced immune response to the vaccine could mean for whether people experience severe illness from COVID-19 infection. That information will be really important to help people understand their risk.