The research, published Tuesday in the scientific journal The Lancet Infectious Diseases, analyzed how 500,000 people responded to two doses of the Pfizer / BioNTech vaccine and the first dose of the one developed by AstraZeneca / Oxford.
The analysis concluded that 25.4% indicated that they experienced side effects, between one and two days after vaccination, while 66.2% showed complaints in the part of the arm where the vaccine was administered.
The report also differentiated vaccines and doses: 13.5% of respondents experienced side effects after receiving the first dose of Pfizer, 22% after receiving the second dose and 33.7% after receiving the first dose of AstraZeneca – now called Vaxzevria.
Among the most common side effects are headache (7.8% after the first dose of Pfizer and 13.2% after the second dose; 22.8% after the first dose of AstraZeneca), fatigue, chills, dizziness, diarrhea, fever, joint pain, muscle pain and nausea.
At the injection site, the most common effects are pain, swelling, tenderness, stiffness, heat, and inflammation of the axillary glands.
The study also found that people who had previously had covid-19 were three times more likely to experience side effects after being vaccinated with two doses of Pfizer and twice in the case of AstraZeneca.