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Vaccine Effectiveness and MS


Last Updated: May 21, 2021
Información disponible en español.

Some DMTs may reduce the effectiveness of the COVID-19 vaccines

People taking certain DMTs (ocrelizumab, rituximab, ofatumumab, and possibly fingolimod, siponimod, ozanimod, ponesimod and others) will have a reduced and possibly undetectable antibody response to the COVID-19 vaccines. If you use one of these DMTs and take an antibody test following your vaccine, it may show a decreased or undetectable antibody level. Even if your antibodies are undetectable or low, you could be protected from COVID-19 since other components of the immune system are triggered by the vaccine and could contribute to your protection.

While easiest to measure, antibodies are not the only post-vaccine response which helps protect us. Research is underway to explore these other components of the immune response to the vaccine and how they might play a role in protection against COVID-19.

The US Food and Drug Administration (FDA) states that antibody tests should not be used to determine immunity or protection against COVID-19

Antibody tests are helpful to determine if someone may have been exposed to the SARS-CoV-2 virus (the virus that causes COVID-19) and may have developed an immune response. Antibody tests should not be used to determine immunity or protection against COVID-19, especially after a person has received a COVID-19 vaccination. Learn more from the FDA.

Even after you’ve been fully vaccinated, continue to take precautions against COVID-19

Even though the current COVID-19 vaccines are highly effective, some people can still become infected with COVID-19 and give it to others. While research on the immune response to the vaccines in MS (described above) is underway, the safest approach is to ensure those closest to you are vaccinated. When in settings where you are unsure of the vaccination status of those around you, continue to wear a mask, practice physical distancing, wash your hands frequently and follow local rules about getting tested for COVID-19 when necessary.


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