The early months of the COVID-19 pandemic were defined by one universal human attribute: fear. Specifically, fear of the unknown, the media reported the high number of global deaths from the pandemic on a daily basis, and insufficient research meant that the scientific community simply did not have enough information in the beginning on how it spreads and how best to stop it. 

Scientific advisories constantly changed as more research uncovered more evidence; for example, in the United States, mask mandates were initially opposed by scientists before being recommended for all. There were also debates on the appropriate levels of social distancing, as well as just how lethal the virus was. 

Writing this article in the second half of 2022, the immediate threat of the virus has abated, thanks in large part to the success of the vaccination programs rolled out worldwide. The quest to find better and more targeted therapeutics for COVID-19 continues, but the pandemic has sufficiently subsided for both researchers and physicians to reflect on their experiences in treating particular diseases under pandemic conditions. 

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In this article, we will focus on the experience of physicians in treating patients with neuromyelitis optica spectrum disorder (NMOSD) during the COVID-19 pandemic. 

Managing Patients With NMOSD During the Pandemic 

One of the defining fears experienced by people all around the world was the uncertainty at what makes a person vulnerable to respiratory infection. At the early stages of the pandemic, it appeared that the virus killed at random, causing widespread panic. Slowly it emerged that the virus was more likely to be lethal in patients with existing comorbidities and that some patients remain completely asymptomatic. 

Read more about NMOSD epidemiology

What do we know about NMOSD and susceptibility to COVID-19 respiratory infection? The answer is that we simply do not have enough data to draw a conclusion on whether preexisting NMOSD puts patients at a higher risk of developing COVID-19 respiratory infection. However, studies indicate that infection-related healthcare utilization was higher in this group of individuals during the pandemic compared to the general population. 

The health advice for patients with preexisting NMOSD was generally the same as for the rest of the population: frequent hand washing, social distancing, and the maintenance of respiratory hygiene at the highest standards. Patients were advised to present themselves to designated healthcare facilities should they experience symptoms of COVID-19 infection, such as fever, cough, and dyspnea. 

One piece of health advice that was specific to patients with NMOSD was to avoid relapses at all costs. “Relapses in patients with NMOSD may be devastating, and patients should be encouraged to continue therapies for attack prevention including corticosteroids, azathioprine, mycophenolate mofetil, rituximab, tocilizumab, and eculizumab,” Brownlee and colleagues wrote in Neurology. 

Because of the increased risk of infection spread in healthcare facilities, most follow-up appointments were conducted virtually via telemedicine during the pandemic. Granted, this may not always be possible. However, virtual follow-ups are useful for monitoring disease progression, as well as any side effects of recently introduced medications. 

NMOSD Care in Latin America 

In Multiple Sclerosis and Related Disorders, Alonso and colleagues conducted a study that investigated the clinical outcomes of patients with NMOSD in Latin America who were infected with COVID-19. 

The research team looked at healthcare registries from 15 countries in Latin America involving 51 treating physicians. A total of 16 patients with NMOSD were identified and analyzed. 

Alonso et al discovered that a higher proportion of patients with NMOSD were hospitalized when infected with COVID-19 compared to patients with multiple sclerosis. Around a third of the patients died while being on rituximab treatment. The research team also discovered that old age, an increase in the Expanded Disability Status Score (EDSS), and longer disease duration were associated with hospitalization, including admission into the intensive care unit. 

This study covering various Latin American countries suggests that patients with NMOSD suffer from poorer outcomes compared to patients with multiple sclerosis or the general population. 

“This result should be cautiously analyzed because it is possible that a larger cohort could identify a subgroup of patients with risk factors that modify the risk of COVID-19,” Alonso et al wrote. 

Read more about NMOSD therapies

This points to a larger problem when it comes to studying rare diseases in the context of the COVID-19 pandemic: due to its inherent scarcity, it is difficult to find patients who have NMOSD with or without COVID-19 infection. Hence, it may be entirely possible that the 16 patients with NMOSD included in this study all contracted severe forms of COVID-19, meaning that the data does not accurately reflect how the average patient with NMOSD would fare against COVID-19. 

“Further research to combine NMOSD cases globally is needed so it would be necessary to share global data,” the research team recommended. 

Why is it important to study how patients with rare diseases respond in a pandemic that is already on the decline? The answer is simple: so we can better prepare for the next pandemic, whenever it comes. We need to understand how patients with rare diseases respond when coming into contact with a highly infectious virus so that we can plan an effective therapeutic response from the very beginning. That way, medical decision-making can be guided by facts and data, as opposed to panic and fear. 


Brownlee W, Bourdette D, Broadley S, Killestein J, Ciccarelli O. Treating multiple sclerosis and neuromyelitis optica spectrum disorder during the COVID-19 pandemicNeurology. Published online June 2, 2020. doi:10.1212/WNL.0000000000009507

Alonso R, Silva B, Garcea O, et al. COVID-19 in multiple sclerosis and neuromyelitis optica spectrum disorder patients in Latin America: COVID-19 in MS and NMOSD patients in LATAMMult Scler Relat Disord. Published online March 7, 2021. doi:10.1016/j.msard.2021.102886