Are there different recommendations for different MS therapies?
On the issue of vaccine effects in patients taking various disease-modifying treatments, the statement says that the data on this are limited. Patients taking interferons, glatiramer acetate, teriflunomide, and fumarates whose lymphocyte counts are normal will most likely be adequately protected. Patients with moderate to severe lymphopenia may not mount an adequate immune response to COVID-19 vaccination, so absolute lymphocyte count may be checked before vaccination.
Patients taking natalizumab will also likely be protected with COVID vaccination.
It is likely that for patients taking alemtuzumab, immune cellular and humoral response to COVID-10 vaccines will be attenuated, especially in the first 6 months during maximum lymphopenia. If possible, vaccination should be delayed until at least 6 months after treatment. It is thought that patients who have completed both courses of alemtuzumab with complete immune reconstitution will mount a full immune response.
In studies, all patients with MS who were treated with cladribine demonstrated a protective humoral immune response to the COVID-19 vaccine. In those studies, the antibody response was evident about 4 months after the last treatment dose, and the titer did not differ from that of healthy persons, Dr. Farez reported.
Low antibody level with fingolimod
The majority of patients treated with fingolimod have failed to show a protective level of antibodies following COVID-19 vaccination, the statement notes.
Asked whether patients taking fingolimod should receive a COVID vaccination, Dr. Farez said that that was a good question. “We have to think about what is an immune response. Antibodies are only a small fraction of all immune responses. So, until we have data to show otherwise, I think we should vaccinate – any immunity is better than no immunity,” he said.
Dr. Farez also suggested that patients with MS who are taking fingolimod should continue to do so. “Any treatment for MS is better than none. If fingolimod is stopped, MS may rebound. So, the most likely scenario would be to keep treating with fingolimod and to give the vaccination. But these patients may need a more aggressive booster approach – we will be looking at that,” he said.
Anti-CD20 antibody drugs
Patients taking ocrelizumab also do not mount an appropriate antibody response regardless of lymphocyte count or the time interval from the last ocrelizumab dose (3-9 months), the statement says. To optimize vaccine efficacy and to balance benefits and risks, the statement advises administering COVID vaccines at least 12 weeks after administering ocrelizumab and 4-6 weeks prior to the next dose, whenever possible.
A study by Apostolidis and colleagues provides strong evidence of immune priming by COVID vaccination in patients treated with anti-CD20 medications. Although for most of these patients, antibody responses are not optimal, T-cell priming is largely intact, Dr. Farez noted.
Booster doses/antibody tests
The need for and timing of COVID vaccine booster doses have not been established. “This is being discussed now for the general population. The recommendations for MS patients will not differ significantly from those for the general population, apart from perhaps for specific populations such as those on anti-CD20 drugs or fingolimod,” Dr. Farez said.