[Suspected allergy to COVID-19 vaccines: A retrospective study of 320 patients]. / Suspicion d'allergie aux vaccins anti COVID-19 : étude rétrospective sur 320 patients.

Introduction: The health context with COVID-19 pandemic has led to fast development of many vaccines against the SarS-Cov-2 virus. Four of them are currently available in France and contain polyethylene glycol (PEG) or polysorbate 80 as excipients, already described as causing anaphylaxis. French recommendations have been suggested by allergology authorities and proposed a course of action in the event of a suspected allergy to these vaccines. Thus, allergies to excipients were the only contraindication to COVID-19 vaccination. Our main objective was to determine the impact of these allergology vaccine recommendations on the management of these patients. Our secondary objective was to determine prevalence of true allergies to these vaccines. Materials and methods: We conducted a unicentric descriptive retrospective study with all patients over 18 years of age referred for an allergological opinion before or after an injection of one of the anti-COVID-19 vaccines. Nineteen patients were classified into different interest groups, based on french recommendations. Results: The vast majority of patients did not require a pre-vaccination allergological assessment. Indeed, only 25 patients received skin tests prior to vaccination. The rest of patients were able to be vaccinated without allergological assessment. Patients not vaccinated due to allergy to excipients represent less than 1% of the population (n = 3/320). Conclusion: French recommendations made it possible to vaccinate the vast majority of patients included in our study. Allergy to PEG, polysorbate or their derivatives, the only contraindication to anti-COVID vaccination, according to the recommendations of February 2021, remains rare. Today, several authors propose tolerance inductions allowing the vaccination of patients allergic to PEGs or their derivatives with good tolerance.

Suspicion d'allergie aux vaccins anti-COVID-19 : étude rétrospective sur la prise en charge de 320 patients

Déclaration de liens d’intérêts: Les auteurs n’ont pas précisé leurs éventuels liens d’intérêts.

Covid-19 vaccines and Guillain-Barré syndrome: A perspective from spontaneous report data

Introduction: The causal relationship between Guillain-Barré syndrome (GBS) and vaccination is still disputed. Our aim was to assess the association between GBS and mRNA (Tozinameran and Elosameran) or adenovirus-vectored (ChAdOx1 nCoV-19 and Ad26.CoV2.S) vaccines. Material and methods: Spontaneous reports of GBS following mRNA-based or adenovirus-vectored vaccination were extracted from Vigibase®. For countries with both available exposure data obtained from Our World in Data website and national incidence of GBS, estimation of the reporting rates and an observed-to-expected (OE) analysis based on the background incidence using a 21-and 42-day risk window were performed. Results: A total of 2,499 cases were included with adenovirus-vectored vaccines in 1,157 (46.3%) and mRNA-based vaccines in 1,342 (53.7%). Sex ratio was 1.09 and median age 57 years (IQR 45-66). The reporting rates per 100,000 person-years within the 42-day window were 5.57 (95% CI, 5.13-6.03) for adenovirus-vectored vaccines and 1.39 (95% CI, 1.31-1.47) for mRNA vaccines compared to a background incidence of 1.2 to 3.1 per 100,000 person-years. For mRNA-based vaccines, the OE was lower than 1 for both risk windows in all European countries and slightly elevated only for the 21-day risk window in the US. For adenovirus-vectored vaccines, the OE ratio was consistently above 2.0 across countries and for both risk windows. Sensitivity analyses using scenarios based on an under-reporting rate of 50% and estimates of confirmed cases of GBS ranging from 55% to 76%, minimally altered these results. Discussion/Conclusion: These findings both suggested the absence of safety concern for GBS with mRNA vaccines and a small increased risk with adenovirus-vectored vaccine. Despite some evidence of differential reporting between countries, our study based on a high number of cases of GBS together with exposure data offered unique opportunities to address the relevance of spontaneous reporting of rare events for epidemiological purposes.

Recurrence of adverse events of special interest after COVID-19 vaccines rechallenge: A Vigibase® study

Introduction: Since the beginning of vaccination against COVID-19 in 2020, the occurrence of adverse events of special interest (AESI) after the 1st dose of vaccine raises the question of the potential risk associated with the following injections. Real-life vaccine data collected in pharmacovigilance databases can provide information about the safety of a rechallenge with COVID-19 vaccines. In order to help physicians to decide whether another injection is at risk, we analyzed the cases reported in the WHO pharmacovigilance database, Vigibase®. Material and methods: We identified AESI with major concerns about the safety of a rechallenge with COVID-19 vaccines: facial paralysis, immune thrombocytopenia, herpes viral infections, hypertension, hearing loss, Guillain-Barré syndrome (GBS), convulsions, myelitis, encephalitis, myocarditis, pericarditis and acute pancreatitis. We extracted cases with rechallenge of these AESI from VigiBase®, whether the AESI recurred or not, until 24 November 2021. The rate of recurrence of the initial AESI according to the vaccine platform was calculated. Results: 676 cases of AESI with COVID-19 vaccines reported information of recurrence after rechallenge, 320 with positive recurrence and 356 with no recurrence. Facial paralysis, herpes viral infection, GBS and myocarditis mostly did not reccur whatever the vaccine type. Whereas hypertension, hearing loss, convulsion and pericarditis seemed to reoccur only after rechallenge of mRNA vaccines, compared to others vaccines. There were few data for immune thrombocytopenia, encephalitis, myelitis and acute pancreatitis. Discussion/Conclusion: This study provided information about the safety of rechallenge of COVID-19 vaccines after first occurrence of AESI. Such information is of great importance considering that several booster shots are being proposed to populations to improve protection against COVID-19 variants. In case of AESI after COVID-19 vaccine, the decision to maintain the following dose must take into account the patient's individual risk benefit balance as well as his history. Although limited, our results provide clinical elements that may help decision-making.