Incidence of Guillain-Barré syndrome following SARS-CoV-2 immunization: Analysis of a nationwide registry of recipients of 81 million doses of seven vaccines.

BACKGROUND AND PURPOSE: Information on Guillain-Barré syndrome (GBS) as an adverse event following immunization (AEFI) against SARS-CoV-2 remains scarce. We aimed to report GBS incidence as an AEFI among adult (≥18 years) recipients of 81,842,426 doses of seven anti-SARS-CoV-2 vaccines between December 24, 2020, and October 29, 2021, in Mexico. METHODS: Cases were retrospectively collected through passive epidemiological surveillance. The overall observed incidence was calculated according to the total number of administered doses. Vaccines were analyzed individually and by vector as mRNA-based (mRNA-1273 and BNT162b2), adenovirus-vectored (ChAdOx1 nCov-19, rAd26-rAd5, Ad5-nCoV, and Ad26.COV2-S), and inactivated whole-virion-vectored (CoronaVac) vaccines. RESULTS: We identified 97 patients (52 males [53.6%]; median [interquartile range] age 44 [33-60] years), for an overall observed incidence of 1.19/1,000,000 doses (95% confidence interval [CI] 0.97-1.45), with incidence higher among Ad26.COV2-S (3.86/1,000,000 doses, 95% CI 1.50-9.93) and BNT162b2 recipients (1.92/1,00,000 doses, 95% CI 1.36-2.71). The interval (interquartile range) from vaccination to GBS symptom onset was 10 (3-17) days. Preceding diarrhea was reported in 21 patients (21.6%) and mild COVID-19 in four more (4.1%). Only 18 patients were tested for Campylobacter jejuni (positive in 16 [88.9%]). Electrophysiological examinations were performed in 76 patients (78.4%; axonal in 46 [60.5%] and demyelinating in 25 [32.8%]); variants were similar across the platforms. On admission, 91.8% had a GBS disability score ≥3. Seventy-five patients (77.3%) received intravenous immunoglobulin, received seven plasma exchange (7.2%), and 15 (15.5%) were treated conservatively. Ten patients (10.3%) died, and 79.1% of survivors were unable to walk independently. CONCLUSIONS: Guillain-Barré syndrome was an extremely infrequent AEFI against SARS-CoV-2. The protection provided by these vaccines outweighs the risk of developing GBS.

Neurologic adverse events among 704,003 first-dose recipients of the BNT162b2 mRNA COVID-19 vaccine in Mexico: A nationwide descriptive study.

mRNA vaccines against SARS-CoV-2 are remarkably effective. Limited information exists about the incidence of adverse events following immunization (AEFI) with their use. We conducted a prospective observational study including data from 704,003 first-doses recipients; 6536 AEFI were reported, of whom 65.1% had at least one neurologic AEFI (non-serious 99.6%). Thirty-three serious events were reported; 17 (51.5%) were neurologic (observed frequency, 2.4/100,000 doses). At the time of writing this report, 16/17 cases had been discharged without deaths. Our data suggest that the BNT162b2 mRNA COVID-19 vaccine is safe; its individual and societal benefits outweigh the low percentage of serious neurologic AEFI. This information should help to dissipate hesitancy towards this new vaccine platform.