December 13, 2021 | News | Living with MSMS Treatments

Omicron: what does it mean for MS?

The emergence of the Omicron variant (B.1.1.529) in November raised new concerns about the COVID-19 pandemic and further fuelled uncertainty in the community of people with multiple sclerosis. According to the U.S. Centers for Disease Control, Omicron was first identified in Botswana and rapidly spread worldwide ( Within two weeks, cases had been reported in Canada. The first case of Omicron was detected in the U.S. on December 1 and has now been reported in 23 states (as of December 10).

What makes Omicron different from other variants (such as Delta, the dominant strain at the moment) is the high number of mutations it carries, including 26-32 mutations in its spike protein. The Spike is how the virus attaches to cells in the body and is the main target for vaccines. This has raised the possibility that Omicron will be more easily transmitted from person to person, and may be better at evading detection by the body’s immune defences.

It is not known if Omicron will cause more severe disease; the variant carries such a high load of mutations that it may be less viable. But thus far, it does appear to be uniquely capable of causing COVID-19 infection in people who have been vaccinated, which suggests that it has some ability to evade detection by the immune system (and vaccines).

While little is known about Omicron, two key points can already be made. The first is that variants of the CoV-2 virus will continue to emerge if the virus is allowed to spread. It is no accident that Delta and Omicron appeared in countries where a low proportion of the population is fully vaccinated (India 36.1%, Botswana 22.5%). Greater efforts will be needed in the coming months to ensure a more equal distribution of vaccines to developing countries.

Secondly, Omicron underscores the importance of vaccination – especially for vulnerable populations such as the MS community. While people with MS do not appear to have a higher risk of contracting COVID-19, they do have an estimated 24% higher risk of dying from COVID (Prosperini and colleagues. J Neurol 2021; epublished September 17, 2021). This is likely due to the higher proportion of people with MS who have COVID risk factors, such as disability and other medical illnesses.

Thus far, laboratory studies have indicated that the current COVID vaccines do provide some protection against the Omicron variant and probably will prevent severe disease. But the immune response is substantially less robust against Omicron compared to the other strains. This appears to be what we are seeing: a rising number of COVID cases that is not matched by a comparable rise in the number of hospitalizations.

The current evidence suggests that a third booster dose is needed to top up the immune response and provide better protection. Over the next few months, at-risk groups – including people with MS – will likely be advised to get a booster shot, which is usually recommended at least six months after completing the usual two-dose regimen (e.g. if you received your second vaccine dose in July, you would be eligible for a booster in January). A booster shot is especially important in people who are taking certain MS medications, such as Ocrevus or Gilenya. And it is important to note that getting vaccinated does not mean that you will need to stop treating your MS – protecting yourself against one does not mean you need to stop protecting yourself against the other.

However, it is important to acknowledge that many people with MS have avoided COVID vaccination altogether. In fact, in a recent survey by the Alliance for Patient Access, 29% of people with autoimmune disorders (including MS) said they were not fully vaccinated ( This is comparable to the unvaccinated rate in the U.S. and is somewhat higher than the unvaccinated rate in Canada.

In many cases, people were avoiding COVID vaccination because they were concerned about vaccine side effects, and worried that the vaccines would make their MS worse. It is probably no coincidence that a higher proportion of these vaccine-hesitant people relied on family, friends and social media for their information about vaccine side effects instead of more reliable sources, such as their family doctor or other health professional.

It is certainly reasonable to have concerns about vaccine safety, and fortunately several studies have now specifically looked at this issue in people with MS.

According to iConquerMS, described as an online people-powered research network, most people did indeed experience some kind of side effect from COVID vaccination (Briggs and colleagues. Neuroimmunol Neuroinflamm 2021; epublished November 9, 2021 As expected, 54% experienced pain at the site of injection. Other reactions included pain or redness where they injected, fever, muscle aches and headache – symptoms that many people taking an injectable MS medication will recognize. These are the same symptoms that people without MS experience when they are vaccinated against COVID, or children when they are immunized against measles and mumps.

A study in Israel looked at whether the Pfizer vaccine could trigger a relapse in people with MS (Achiron and colleagues. Mult Scler 2021;27:864-870). Overall, about 2% of people experienced a relapse in the six weeks after vaccination – about the same relapse rate seen in people who were not vaccinated. To put this into perspective, the risk of relapse appears to be higher if an unvaccinated person with MS gets sick with COVID (Havla and colleagues. J Neurol 2021; epublished June 11, 2021). So it is unfair to say that vaccination was the cause of a relapse. Vaccination will also prevent the development of ‘long COVID’ – a worrisome complication we would be well advised to avoid.

Public health measures – such as vaccination and wearing a mask – are an inconvenience but they are necessary and effective. A recent analysis found that the spread of COVID was reduced by 53% with frequent handwashing, 53% with masks and 25% with physical distancing (Talic and colleagues. Br Med J 2021;375:e068302). So these measures will need to be maintained (even if you have had a booster shot) as people get together with family and friends over the holidays.

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