A Nationwide Survey of mRNA COVID-19 Vaccinee’s Experiences on Adverse Events and Its Associated Factors

"Introduction

... This study aimed to investigate a population-based safety profile of mRNA COVID-19 vaccines and to identify factors associated with participant-reported AEs [adverse events] following mRNA COVID-19 vaccination using nationally representative survey data generated from a population aged between 18–49 years in Korea...

Results

Totally 2,849 adults participated in the survey, with a median (IQR) age of 35 (27–42) years...

Among participants receiving the mRNA COVID-19 vaccine, 90.8% of the first dose and 88.7% of the second dose reported AEs; those with severe AEs were 3.3% and 4.3%, respectively. The incidence of AEs following mRNA-1273 [Moderna] was higher than that of BNT162b2 [Pfizer] at both doses: first dose (93.5% vs. 89.9% for any AEs; 4.8% vs. 2.9% for severe AEs) and second dose (95.0% vs. 87.0%; 5.8% vs. 3.9%)...

While all AEs were more predominant in mRNA-1273 than in BNT162b2, the odds were particularly higher for systemic AEs at the second dose (OR, 2.92; 2.27−3.77). For both mRNA COVID-19 vaccines, the incidence of systemic AEs increased at the second dose compared to that at the first dose, whereas the incidence of local AEs decreased...

Discussion

... Substantial factors, including vaccination with mRNA-1273, first dose, female sex, and dermatologic diseases were associated with AEs. Additionally, the second dose, history of serious allergic reactions, and anticoagulant medication use in the past six-months were associated with greater odds of severe AEs...

Among the factors that may have an impact on AEs, the vaccine type was the most significant. Particularly, mRNA-1273 was significantly associated with higher odds of AEs than BNT162b2...

A notable finding was that over 15% of female participants reported menstrual disorders and unexpected vaginal bleeding after mRNA vaccination."