On Oct. 8, 2020, the relation between COVID-19 and Guillain-Barre syndrome (GBS) in adults: a systematic review was published in Neurology. The review was conducted of 45 studies, which were analysed and completed using the Covidence platform; the final analysis included 24 articles, with a total of 30 patients. published on scientific databases: PubMed, Cochrane, Science Direct, MEDLINE, and WHO COVID-19 database.

GBS is a severe condition that manifests when the immune system attacks the patient’s own body, and specifically the cells of the peripheral nervous system. The cause is not clear, but this immune disorder is frequently associated with other viral or bacterial pathologies, including influenza, HIV, and herpes virus infection; an association with COVID-19 is currently being studied. While GBS may manifest at any age, its incidence is highest among individuals aged 30-50 years. It is considered a demyelinating disease because the lesions mainly affect myelin in the peripheral nerves, leading to paresis, muscle weakness, and even bilateral ascending paralysis. If nerve damage reaches the diaphragmatic nerves, the patient may present respiratory symptoms ranging from mild respiratory failure to the need for invasive ventilatory support. Unfortunately, GBS is incurable; treatment focuses on symptom management and ventilatory support, when needed

Of the 47 articles identified in the literature search, we excluded 7 duplicate studies, and a further 15 were excluded during the review of titles and abstracts; of the remaining 25, we excluded one during the review of full texts due to the study design. We finally included 24 studies for data gathering, analysis of results, and quality assessment. A total of 30 patients were included. Sex and age were not reported in 5 cases (16.6%); and of the remaining 25, 14 were men (46.6%) and 11 women (36.6%).

The majority of studies included used PCR testing to detect SARS-CoV-2, with positive results in most of the patients; only 3 studies reported negative PCR tests, including the study by Molina et al. who classified the results as a false negative due to the presence of confirmed cases of COVID-19 among the patient’s family members. The study by Reyes-Bueno et al reported negative results in the PCR test but positive IgG test results; the study by Toscano et al. reported 5 patients, only one of whom presented negative results in the PCR test. The study by Kilinc et al. is also noteworthy: it does not report PCR testing but rather IgM and IgG tests only, both with positive results.

The studies analysed show a clear association between both pathologies, with SARS-CoV-2 potentially triggering GBS. Further studies providing higher levels of evidence and including more representative samples are needed for a conclusive analysis of this topic; however, these cases seem to differ from those reported before the pandemic in the older age of onset and more severe clinical manifestations and cranial nerve involvement. In any case, appropriate treatment achieves favourable outcomes.