Risk Analysis of Guillain-Barré Syndrome Reported as an Adverse Effect Following Covid-19 Vaccination in the State of Espírito Santo

COVID-19 vaccination was essential for reducing morbidity and mortality during the pandemic. However, like any medical intervention, it is subject to adverse effects. Among these, Guillain-Barré Syndrome (GBS), an acute inflammatory neuropathy of the peripheral nervous system, has been reported in temporal association with vaccination. Investigation of these cases is fundamental to assess risks and strengthen immunization safety. This study aimed to describe GBS cases reported to the Health Department as temporally related to COVID-19 vaccination in the state of Espírito Santo (ES), analyzing the clinical-epidemiological profile, type of vaccine, outcomes, and the proportion of cases in relation to the total number of doses administered. Case series study of GBS reported in the health surveillance system of the State Health Department of ES in association with COVID-19 vaccination from January 2021 to April 2023. Between 2021 and 2023, Espírito Santo administered 10,489,904 doses of COVID-19 vaccines (AstraZeneca, Pfizer, Coronavac, and Janssen), with 6,593 adverse events recorded. These ranged from mild reactions, such as fever and injection-site pain, to more severe cases like GBS. The overall incidence of adverse events was 62.9 per 100,000 doses, with only 15 GBS cases (0.14 per 100,000 doses), a very low rate given that the expected incidence in the general population is 1 to 2 cases per 100,000 people. There were 4 cases in women and 11 in men, most older than 40 years. There were 7 cases associated with AstraZeneca (0.22/100,000 doses), 2 with Janssen (0.33/100,000), 5 with Pfizer (0.10/100,000), and 1 with Coronavac (0.05/100,000). Cases occurred on average 12 days after vaccination. COVID-19 vaccination did not increase the overall risk of GBS in Espírito Santo. Although individuals vaccinated with adenoviral vector vaccines showed a higher proportional number of GBS reports in the state surveillance system compared with those vaccinated with mRNA vaccines, all reported rates remained below the expected incidence of GBS. In summary, no significant increase in the annual incidence of the syndrome was observed among vaccinated individuals in Espírito Santo.