OBJECTIVE Side effects of vaccines are common, but people react differently to different vaccines. Manufacturers provide lists of the side effects of their products. Adverse reactions are proof of the effectiveness of vaccines and that the immune system is responding. In this study, we compare the side effects of the AstraZeneca and Pfizer vaccines. Our survey results show that the side effects of the first dose of the AstraZeneca vaccine are more common than after the first and second doses of the Pfizer vaccine. Most respondents in our survey reported at least one side-effect after the AstraZeneca and Pfizer vaccine, but these reactions were less common after the Pfizer preparation. PATIENTS AND METHODS A survey was distributed via the internet. It was conducted among people vaccinated with Pfizer or AstraZeneca. The respondents were asked about the side effects after the first and second doses of the vaccines, such as injection site pain, arm pain, muscle pain, headache, fever, chills, and fatigue. RESULTS The questionnaire was completed by 705 people. 196 of them had been vaccinated with Pfizer and 509 with AstraZeneca. Among those vaccinated with the first dose of the AstraZeneca vaccine, 96.5% reported at least one post-vaccination reaction. 17.1% of respondents reported all the side effects listed in the survey. Among those vaccinated with the first Pfizer dose, vaccine reactions were reported by 93.9% of respondents; 2% of respondents experienced all the side effects mentioned in the survey. The second dose of the Pfizer vaccine caused post-vaccinal reactions in most of the subjects: 54.8% of respondents had more adverse reactions, and 15.8% had fewer adverse reactions than after the first dose of this vaccine; 29.4% experienced the same side effects after the first and second doses of the Pfizer vaccine. CONCLUSIONS Side effects as a result of vaccination are not rare and are proof that the immune system is responding. However, severe adverse reactions to vaccines can be dangerous, and they engender fear. Concerns about the side effects and complications of COVID-19 vaccines may eclipse opinions regarding their benefits. This study shows that the first dose of the AstraZeneca vaccine causes side effects more often than either dose of the Pfizer vaccine.
Side effects after COVID-19 vaccinations among residents of Poland.