MS and COVID in 2022: a look ahead
A late surge in COVID-19 cases caused by the Omicron variant means that the pandemic will continue to be at centre stage through much (hopefully not all) of the coming year. As of January, about 321 million people worldwide had been infected and over 5.5 million people had died. The U.S. has been hardest hit with over 65 million cases and over 860,000 deaths. The U.S. ranks 14th in COVID mortality rate (260 deaths per 100,000 population) after Peru (603), Bulgaria (464), Bosnia/Herzegovina (422), Hungary (418), Montenegro (392), North Macedonia (387), Georgia (361), Czechia (342), Croatia (320), Slovakia (314), Romania (310), Brazil (288), and Poland (269). Canada has seen 2.6 million cases and 31,190 deaths (mortality 81/100,000).
While vaccines have been remarkably effective in preventing severe COVID, there is some evidence that protection declines with time. A U.K. study published in January 2022 looked at over two million COVID test results in people who had two doses of the Pfizer vaccine (Andrews and colleagues. N Engl J Med, epublished January 12, 2022). While vaccine effectiveness in preventing COVID symptoms was high (about 90%) in the first two months after the second dose, the effectiveness declined to 66% after five months (55% in people aged 65 or older). At 5 months, vaccination was also 66% effective in preventing hospitalization in high-risk individuals and 92% effective in preventing death from COVID.
To put these numbers into context, many vaccines (such as the seasonal flu shot) are less than 66% effective. So despite much talk about waning immunity, COVID vaccines do continue to confer a high degree of protection against the more severe outcomes.
However, the study only considered the Alpha and Delta variants and did not account for the Omicron variant. So there is some uncertainty about how effective the initial two doses of vaccine will be against Omicron (which is only halfway through the Greek alphabet). As a result, expert panels, such as Canada’s National Advisory Committee on Immunization (NACI), have recommended that people get a booster shot (www.canada.ca/en/public-health/services/immunization/national-advisory-committee-on-immunization-naci/guidance-booster-covid-19-vaccine-doses.html). [NACI fusses over whether a third dose should be called a ‘booster’, meant to enhance a prior response, or a third shot in a three-dose vaccination.] NACI’s recommendation is that people aged 50 years or older and at-risk groups (which arguably includes people with MS) should get a booster. Boosters may also be offered to younger people than age 50. Since that recommendation in December, many jurisdictions have recommended booster shots for all adults.
Prior to the Omicron outbreak, the MS Society of Canada recommended booster shots for people with MS taking certain disease-modifying therapies (https://mssociety.ca/resources/news/article/ms-society-advocates-for-covid-19-vaccine-boosters-for-immunocompromised-individuals-with-ms). The treatments of concern were Rituxan, Ocrevus, Kesimpta, Gilenya, Zeposia, Ponvory, Lemtrada and Mavenclad. (The National MS Society does not include Mavenclad on its list.) The issue was that people taking any of these medications, which suppress the immune response, may have had an inadequate response to the first two doses of vaccine.
People on one of these medications are advised to talk to their neurologist about the optimal timing of the booster shot. There are no current recommendations from the Canadian Network of MS Clinics (https://mssociety.ca/library/document/HwgNMDVlkubJmqFvi1XZOyjA4e2z65tS/original.pdf).
But it is likely that the optimal timing of the booster will be similar to what was advised for the first two shots:
- Ocrevus and Rituxan: get the booster about 4-6 months after the last infusion.
- Kesimpta: get the booster about 4 weeks after the last injection.
- Lemtrada: get the booster at least 3 months after the last infusion.
With Gilenya, Zeposia, Mayzent and Ponvory, it is better to keep taking the medication and get the booster whenever an appointment becomes available. No special timing of the booster shot is needed for people taking Mavenclad.
All of the other MS treatments – Copaxone, the interferons, Tecfidera, Aubagio and Tysabri – do not appear to affect vaccine response. However, people taking any of these medications are also advised to get a booster shot to maximize protection against Omicron. No special precautions are needed with respect to the timing of these medications. A booster shot can be administered for whenever an appointment can be scheduled.
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