RESUMEN
OBJECTIVE: To perform a nationwide epidemiological study of Guillain-Barre syndrome (GBS) in Spain, analysing background incidences and seasonal variation and trying to identify incidence changes during the COVID-19 years. METHODS: Observational study collecting all GBS diagnoses from National Epidemiological Surveillance Network (RENAVE) collected by the Ministry of Health. Patients discharged with GBS as main diagnosis and admitted during 2018-2021 were included. Data on the incidence of SARS-CoV-2 infections and vaccinations were obtained from the National Epidemiology Centre. RESULTS: In total, 3147 cases were included, 832 in 2018, 861 in 2019, 670 in 2020 and 784 in 2021. Nationwide hospital incidence was 1.78 in 2018, 1.71 in 2019, 1.41 in 2020 and 1.66 in 2021, with an increased frequency in males, elderly population, and in the winter season. Eleven percent of GBS patients needed ventilatory support. GBS and SARS-CoV-2 incidences did not correlate with one another (r=-0.29, p=0.36). GBS incidence decreased during 2020 and during COVID-19 lockdown period in comparison to the same months of 2018-2019. No relationship was found between vaccines and GBS cases during vaccination roll-out in 2021. INTERPRETATION: Incidence of GBS in Spain is similar to that of other countries. Despite prior reports describing a significant increase in COVID-19-associated GBS in Spain, we detected a significant drop of GBS incidence during the SARS-CoV-2 pandemic, probably due to prevention measures. No relationship was found between SARS-CoV-2 or vaccinations and GBS incidences at the population level but data on relationship of vaccinations and GBS at the individual level were not available.