Immunology of COVID-19 and disease-modifying therapies: The good, the bad and the unknown.

OBJECTIVE

The outbreak of the SARS-CoV-2 pandemic, caused by a previously unknown infectious agent, posed unprecedented challenges to healthcare systems and unmasked their vulnerability and limitations worldwide. Patients with long-term immunomodulatory/suppressive therapies, as well as their physicians, were and are concerned about balancing the risk of infection and effects of disease-modifying therapy. Over the last few months, knowledge regarding SARS-CoV-2 has been growing tremendously, and the first experiences of infections in patients with multiple sclerosis (MS) have been reported.

METHODS

This review summarizes the currently still limited knowledge about SARS-CoV-2 immunology and the commonly agreed modes of action of approved drugs in immune-mediated diseases of the central nervous system (MS and neuromyelitis optica spectrum disorder). Specifically, we discuss whether immunosuppressive/immunomodulatory drugs may increase the risk of SARS-CoV-2 infection and, conversely, may decrease the severity of a COVID-19 disease course.

RESULTS

At present, it can be recommended in general that none of those therapies with a definite indication needs to be stopped per se. A possibly increased risk of infection for most medications is accompanied by the possibility to reduce the severity of COVID-19.

CONCLUSIONS

Despite the knowledge gain over the last few months, current evidence remains limited, and, thus, further clinical vigilance and systematic documentation is essential.