In a recent study published in Neurology - Neuroimmunology Neuroinflammation, researchers investigated the impact of coronavirus disease 2019 (COVID-19) on the progression of clinical disability in multiple sclerosis patients.
Background
Multiple sclerosis is clinically characterized by relapses that involve exacerbated neurological dysfunction with progressive disease involving the slow but continued accumulation of neurological disabilities. While systemic infections are known to worsen the neurological dysfunction and progression of disabilities and increase the risk of relapses, it is still unclear how infections precisely affect the rate of progression of these neurological disabilities. Studies have shown that irrespective of the cause, severe diseases requiring hospitalizations are associated with a significant worsening of clinical impairment in multiple sclerosis patients.
The COVID-19 pandemic resulted in a wide range of severity of symptoms, with a significant number of patients experiencing asymptomatic or mildly symptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections with fever, headaches, and upper respiratory tract infections, but others experiencing severe symptoms such as hypoxia, organ dysfunction, and respiratory failure requiring hospitalization and intensive care. The focus of most COVID-19 and multiple sclerosis-related studies has been to analyze and predict the risk of COVID-19 in patients with multiple sclerosis, or to determine the immune responses of multiple sclerosis patients to SARS-CoV-2 infections or COVID-19 vaccinations. The impact of COVID-19 on the worsening of multiple sclerosis symptoms is not well-explored.
About the study
In the present observational retrospective study, the researchers analyzed the impact of contracting a SARS-CoV-2 infection and the severity of the infection on the worsening of clinical disabilities in multiple sclerosis patients. The clinical data collected from the patients included a COVID-19 diagnosis based on a confirmed positive polymerase chain reaction (PCR) test, as well as information on the gender and age of the patients, the COVID-19 diagnosis date, the severity of the SARS-CoV-2 infection, outcomes, COVID-19 vaccination status, the duration of multiple sclerosis, clinical subtype, and the disease modifying treatment being administered at the time of the COVID-19 diagnosis.
The regular testing during routine follow-ups for general disability for multiple sclerosis patients included the expanded disability status scale (EDSS), as well as tests for ambulation or leg function, dexterity or dominant hand function, and information processing speed or cognition. The last two measurements for these parameters before and the one measurement after the COVID-19 diagnosis were used for the evaluation.
The primary evaluated outcome was whether COVID-19 accelerated the worsening of neurological disabilities in multiple sclerosis patients. The relationship between COVID-19 severity and the worsening of clinical disability between T1, which was the time of measurement of disability parameters just before the COVID-19 diagnosis, and T2, which was just after the COVID-19 diagnosis, was explored as a secondary outcome. Other secondary outcomes included the effect of vaccination status on COVID-19 severity in multiple sclerosis patients and the influence of vaccination status on the worsening of clinical disability between T1 and T2.
Results
The results indicated that among multiple sclerosis patients who survived COVID-19, the T1 to T2 worsening on the EDSS was significantly greater than that between T0 and T1, which were both before the COVID-19 diagnosis. However, similar differences were not observed for the ambulation, dexterity, or cognitions test scores.
A total of 234 COVID-19 cases were identified among multiple sclerosis patients, of which 13.2% were hospitalized and 2.1% (5 patients) died due to the infection. Severe COVID-19 requiring hospitalization was associated with a significant worsening of EDSS scores. Unvaccinated multiple sclerosis patients experienced worse COVID-19 outcomes including hospitalization and death, but the unvaccinated status was not associated with a worsening of EDSS scores between T1 and T2.
The authors presented several hypotheses that could potentially explain the underlying mechanisms through which SARS-CoV-2 infections accelerate neurological deterioration in multiple sclerosis patients. The neurological manifestations of COVID-19 such as headaches, stroke, dysgeusia, encephalopathy, and other neurological impairments, indicate that SARS-CoV-2 affects the central nervous system. Furthermore, COVID-19 has been associated with an increase in acute demyelinating central nervous system episodes, and various studies have indicated increased inflammatory responses, all of which suggest that COVID-19 could increase the risk of relapse in multiple sclerosis patients.
Conclusions
Overall, the findings suggested that the occurrence and severity of SARS-CoV-2 infections significantly accelerated the worsening of neurological disabilities in multiple sclerosis patients. While vaccination granted protection against severe COVID-19 outcomes, unvaccinated status was not associated with the worsening of clinical disabilities.