Decreased Incidence of Guillain-Barré Syndrome during the COVID-19 Pandemic: A Retrospective Population-Based Study

Abstract

Background: Guillain-Barré syndrome is an immune-mediated acute inflammatory polyneuropathy that is associated with various triggers, including certain infections and vaccines. It has been suggested that both SARS-CoV2 infection and vaccination may be triggering factors for Guillain-Barré syndrome, but evidence remain equivocal. Here we conducted a population-based incidence study of Guillain-Barré syndrome spanning the three years immediately prior to and the two years during the pandemic. Methods: Cases were identified by searching a regional diagnostic database for the ICD-10 code for Guillain-Barré syndrome. Individuals who fulfilled the Brighton Criteria for Guillain-Barré syndrome were included. Information on clinical presentation, laboratory values, and vaccination status were retrieved from medical records. We calculated the incidence immediately prior to and during the pandemic. Results: The Guillain-Barré syndrome incidence rate was 1.35/100,000 person-years for the pre-pandemic period, and 0.66/100,000 person-years for the pandemic period (incidence rate ratio: 0.49; p = 0.003). Three cases were temporally associated with SARS-CoV2 infection, and one case each to the Astra Zeneca and Pfizer-BioTech COVID-19 vaccines. Conclusions: Our results show that the incidence of Guillain-Barré syndrome decreased during the pandemic. This is most likely due to decreased prevalence of triggering infections, due to social restrictions. Our findings do not support a causal relationship between Guillain-Barré syndrome and COVID-19.

Guillain−Barré syndrome and SARS‐CoV‐2 infection: a systematic review and meta‐analysis on a debated issue and evidence for the ‘Italian factor’

“…On the other hand, during the first five pandemic months, the incidence of GBS in the UK, as derived from the National Immunoglobulin Database, was reduced compared with the same period of the previous 5 years [9]. Similar results were recently reported in South Korean and in Swedish studies [10, 11]. These contrasting findings make the debate on GBS and SARS‐CoV‐2 infection heated.…”

“…The risk of developing GBS in northern Italy during the first COVID‐19 pandemic wave was 2.85 times increased compared with the same period of the previous year, whereas, when considering the first pandemic year, the overall GBS risk was in some countries 0.17 times reduced [7, 8, 10, 11]. In northern Italy the GBS risk decreased from 2.6 in March–April 2020 to 1.41 considering the whole first pandemic year [7, 28].…”

“…Three cohorts were included [10,11,28]. The exact number of GBS cases for each year was obtained on consulting the authors.…”

The Impact of COVID-19 on the Guillain–Barré Syndrome Incidence

“…Conversely, the opposite results were obtained in the UK, where, according to data from the national immunoglobulin database, there was a decrease in the number of cases [69]. A similar situation was also observed in Sweden [70], Korea [71,72], and Portugal [73]. The reduction in the number of GBS cases may be due to the protective measures introduced during the pandemic.…”

Improving Outcome in Severe Myasthenia Gravis and Guillain–Barré Syndrome

“…38 The incidence of GBS can increase during outbreaks of infectious diseases, with the most recent being the Zika virus epidemics in 2013 (French Polynesia) and 2015-2016 (Latin America). 35 While COVID-19 has also been linked with an increase of GBS in some studies, 39,40 data remain conflicting. A large population-based study from Israel found with COVID-19 an increased risk of GBS, while the Pfizer vaccine was associated with a decreased risk of GBS.…”