Precautions still advisable as COVID restrictions relax

A new study has looked at COVID-related risks in people with multiple sclerosis. The findings suggest that it would be prudent to keep taking some precautions against infection even as COVID restrictions are relaxed.

The study looked at data from about 4,300 people with MS who developed COVID-19 (Barzegar and colleagues. Neurol Neuroimmunol Neuroinflamm 2021;8:e1001). People averaged about 45 years of age, had been living with MS for about 12 years and typically had mild disability. About one-third had another medical condition, mostly high blood pressure or diabetes. About 85% were taking a disease-modifying therapy (DMT) for their MS; the most commonly used medications were Ocrevus, Tecfidera, an interferon (e.g. Rebif, Plegridy), Gilenya or Tysabri.

Overall, about 1 in 5 people required hospitalization for their COVID-19. People were more likely to require hospitalization if they were older or had significant disability. The hospitalization rate was very high (43%) in people who were not taking a DMT for their MS. This does not mean that treatment protected them against severe COVID. What it indicates is that the group was not being treated because they were at a phase of their MS in which they would not obtain much benefit from treatment, i.e. people who are older and/or with advanced disease. In the group that was taking a DMT, hospitalization was more common in those receiving Ocrevus.

The overall COVID-related mortality rate among people with MS was 3.0%. This is similar (although slightly higher) than the mortality rate seen in the general population. During the study, global mortality from COVID-19 was 2.2% (2.1% as of May 31, 2021). In Canada and the U.S., the overall mortality rate is 1.8%. A direct comparison cannot be made since the study included people with MS from various countries, and the number of COVID deaths varies widely from country to country.

The slightly elevated mortality rate likely reflects the higher proportion of people in the MS population with disability or other medical conditions who are especially vulnerable to severe COVID compared to the population at large.

In looking at COVID deaths by age group, 19% were in people with MS who were younger than age 50 years, 31% in people aged 50-60 years, and 50% in people older than age 60. As a comparison, in Canada the death rate by age group is 21%, 14.5% and 64.5%, respectively. Again, while direct comparisons cannot be made, these results may suggest that people with MS in their 40s have a higher risk of severe COVID than other people in that age group. That 10-year period is often a critical time. It is when progressive disability may develop, people are often taking a more potent DMT, and there may be other medical conditions that develop. People in their 40s may also be less able to shelter themselves from COVID because of work or family obligations compared to the population at large.

The current wisdom is that people with MS do not have an overall higher risk of developing severe COVID than people without MS. However, those risks do not apply equally across all age groups. And as people get fully vaccinated, it may be best not to assume that you are fully protected against COVID-19. More contagious variant strains of the COVID virus are becoming widespread, and some DMTs appear to reduce the body’s immune response to vaccination. So it is best not to assume that you have full immunity against COVID-19 even after you have received your vaccinations.

Everyone is desperate for life to return to normal. But even as COVID case numbers go down and restrictions ease, it may be prudent for at-risk people to continue to take some precautions: keep the social circle small, avoid crowds, and wear a mask when in a group.

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