COVID-19 VACCINE IN MULTIPLE SCLEROSIS PATIENTS TREATED WITH DISEASE-MODIFYING THERAPIES: a systematic review

INTRODUCTION: Multiple sclerosis is a neurological disease defined by
accumulating immune-mediated damage to the central nervous system, and most of
its patients are immunocompromised. After the COVID-19 pandemic outburst in
2020, it became extremely important to understand the effects of disease-modifying
therapies in the COVID-19 vaccination, as it could be compromised. OBJECTIVE:
The aim of this review is to analyze studies regarding the impact of the disease-
modifying drugs on immunological responses to COVID-19 vaccines in multiple
sclerosis patients. METHODS: This systematic review was executed using PubMED
and Virtual Health Library database, using the following subject headings "Multiple
Sclerosis", "Drug Therapy", "COVID-19" and "Vaccine". The articles were recovered
through the PRISMA methodology showing the following results: 390 articles were
found, of which 208 were excluded after applying the filters (publication year - last 5
years, language - english, full articles), 144 were excluded after reading the titles and
13 excluded after reading the abstracts. 25 were fully read and 19 were included in
this review. RESULTS: Most articles presented results showing that the majority of
disease-modifying drugs allowed satisfactory immune response to COVID-19
vaccination in multiple sclerosis patients. Nonetheless, some studies showed that the
anti-CD20 therapies are at increased risk for insufficient vaccination response, while
the interference of the Fingolimod had variable results. In these cases, it seems to be
beneficial to use a booster dose and a serological monitoring could be required to
assess the immune response. CONCLUSION: Despite some disease-modifying
drugs shown to interfere in the immune response to the COVID-19 vaccine, it is not
recommended to discontinue or modify the treatment to improve vaccine efficacy, as
the risk of disease reactivation and progression outweighs the potential benefits.
Additionally, it is accepted that a reduced response is better than none. Further
studies are needed to clarify the situation.