This systematic review analyzed the prevalence of infections in patients with multiple sclerosis (MS) using disease-modifying drugs (DMDs). MS is a chronic condition that typically leads to progressive disability, but its clinical course can be altered through appropriate treatment. However, because DMDs modulate the immune system, they can increase susceptibility to infections, making a careful assessment of risks and benefits essential when selecting a treatment.

A total of 20 articles were selected from 5,521 identified across four databases (SciELO, Embase, PubMed, and LILACS), all published up to December 2020. The studies included focused on infections in MS patients treated with the following DMDs: glatiramer acetate, beta-interferon, fingolimod, natalizumab, dimethyl fumarate, teriflunomide, alemtuzumab, ocrelizumab, and cladribine. Only cases involving women over 18 years of age were considered.

Among the selected studies, eight were open-label trials and twelve were phase 3 or extension studies. Progressive multifocal leukoencephalopathy (PML) was reported in 20% of the studies, most frequently associated with natalizumab use. A 2016 Brazilian study also reported dengue infection. The most common infections across the studies were upper respiratory tract infections, cited in 8 of the 20 articles. Urinary tract infections followed in prevalence.

The review concludes that a patient's individual risk profile should be thoroughly evaluated before initiating DMD treatment. For patients who cannot tolerate significant risk, first-line therapies are recommended. However, in patients with severe or highly active MS, the use of more potent DMDs is supported—provided that their safety profiles are considered acceptable and the benefits in terms of relapse reduction outweigh the infection risks.

Fernanda Grôppo Nogueira Herculano is a neurologist specialized in multiple sclerosis and neuroimmunology. She graduated in medicine from the fluminense federal university (UFF) in 2014 and completed her medical residency in neurology at the same institution from 2015 to 2018. In 2021, she obtained a master’s degree in neurology from the federal university of the state of rio de janeiro (Unirio), with a thesis focused on the prevalence of infections in patients with multiple sclerosis using disease-modifying drugs. Currently, Fernanda practices as a neurologist in São Paulo, where she works at her private clinic and in leading healthcare institutions. She is primarily dedicated to the care of patients with multiple sclerosis and other neuroimmunological disorders. Additionally, she has participated in clinical research as a sub-investigator and rater, focusing on new therapies for multiple sclerosis and neurodegenerative diseases. Fernanda is the managing partner of the clinic Dra. Fernanda Herculano neurologia, headquartered in São Paulo.