(331) Active Safety Monitoring of COVID-19 Vaccines in France using Patient-Reported Outcomes

Background: In the context of the safety monitoring of COVID-19 Vaccines, the European Medicines Agency requested and promoted a prospective cohort event monitoring study in multi-European countries. This abstract presents the results from France.

Objectives: To estimate incidence rates of patient-reported adverse events (AEs) following COVID-19 vaccination and to identify possible associated risk factors in France.

Methods: Through web applications, vaccine recipients self-enrolled within two days of receiving either the first dose (FD) or a booster dose (BD) of the COVID-19 vaccine. Follow-up was conducted via online standardized forms at 1, 2, 6, 8 weeks and 3 months for both FD and BD recipients, and at 6 months for FD recipients only. Descriptive analysis was completed by a multivariable logistic regression model to identify associated risk factors to reactogenicity and menstrual cycle perturbations. Results present odds ratios with 95% confidence intervals (OR [CI95%]).

Results: From June 2021 to August 2022, 1,549 (FD cohort) and 5,317 (BD cohort) vaccine recipients were self-enrolled in the study (median age 32 / 47 years, women 66% / 59%, respectively). At least one AE was reported by 61% / 60% of vaccine recipients with ≥1 filled follow-up form, of which 5 / 7 were serious AEs. More than 72% / 75% of AEs concerned reactogenicity and 1.7% / 1.1% concerned menstrual cycle perturbations. The factors most strongly associated with reactogenicity were in FD cohort: sex (women OR=2.19 [1.68-2.84]), older age (1.50 [1.02-2.22], 1.91 [1.27-2.88], for [30-40[, [40-50[ years old vs < 18), previous confirmed Covid-19 infection (2.17 [1.47-3.21]), respiratory system treatment at inclusion (2.02 [1.09-3.73]); and in BD cohort: sex (women OR=1.27 [1.10-1.46]), older age (1.52 [1.12-2.06] for [30-40[ years old, vs < 25), reactogenicity after a previous dose injection (4.02 [3.51-4.61]), allergy to insect bites (2.16 [1.14-4.09]) or medication (1.55 [1.12-2.14]), and gastrointestinal and metabolic treatment at inclusion (1.41 [1.05-1.88]). Receipt of ≥1 other vaccine in the 2 weeks before BD was a protective factor for reactogenicity (0.59 [0.42-0.84]). Factors most strongly associated with menstrual cycle perturbations were in FD cohort a previous probable Covid-19 infection (4.63 [1.81-11.89]), and in BD cohort, menstrual cycle perturbations after a previous dose injection (7.39 [4.02-13.60]) and younger age (2.23, 3.24 for < 30, [30-40[ years old vs ≥40).

Conclusions: French results suggest that the risk of reactogenicity following initial or booster vaccination against COVID-19 is associated with the sex and age of vaccine recipients, and with previous infection with COVID-19 or a previous dose injection, which also impacts the risk of menstrual events in women.