Self-reported adverse events within the seven days following the Spikevax® (Moderna) vaccination

Continuous monitoring of COVID-19 vaccines safety may provide  additional information to health care professionals and the general population.  The aim of the present study was to analyze the local and systemic adverse  events following the administration of the Spikevax® (Moderna) vaccine, and  to identify the factors related to greater reactogenicity.

Using a telephone survey, we interviewed 331 recipient of the  Spikevax® vaccine (50.2% men; Meanage = 46.4). Participants  haracteristics, prior COVID-19 infection and local and systemic adverse events  within seven days following the first and second vaccine doses were asked. Results: Injection site pain, fatigue and headache were the most common adverse events. The prevalence and intensity of local events was higher after the first dose, while systemic events were higher in the  second one. Most adverse events were mild/moderate; 1.2% of participants  needed hospitalization or emergency room visit. Women and participants aged  18-55 years were more likely to experience greater reactogenicity, participants  with prior COVID-19 infection had more systemic  events after the first dose, and participants with chronic diseases other than  hypertension reported fewer systemic adverse events following the second  dose.

Our results are consistent with previous studies, identifying women, people aged 18-55 years and those with previous COVID- 19 infection as those who experienced the greatest reactogenicity to the  vaccine. A relationship was also found between reactogenicity and suffering from a chronic disease other than hypertension.