LAUSR

OBJECTIVE The pandemic disease by SARS-CoV-2 infection does not have an effective treatment. To prevent the disease, scientists developed vaccines that the clinicians use as an emergency licensed vaccine. The objective of this study was to determine the side effects in personnel vaccinated at the Military Central Hospital of Mexico with the BNT162b2 vaccine. PATIENTS AND METHODS This study included the subjects who had received both doses of the BNT162b2 vaccine between December 2020 and February 2021. We asked about the side effects after the first and the second vaccine doses. One group had no history of COVID-19, and the second had a history of COVID-19. ANTI-SARS-CoV-2 antibodies were measured by the immunodetection technique in the second group only. RESULTS We included 946 participants, 62% were women, and 80% were without comorbidities; 680 were included in the first group, and only 266 were in the second group. After the first dose, 77% of the first group and 86% of the second group presented some side effects. After the second dose, 84% of the first group and 89% of the second group showed some side effects. The main side effect was mild pain. All participants (126) were IgG positive, and only 26.9% were IgM positive at 17.5 days (12.8 days, 20.3 days) after the second dose. CONCLUSIONS There is a positive correlation between side effects after the first dose in patients with a history of previous SARS-CoV-2 infection compared to those who did not. Nevertheless, this correlation is not present after the second dose. The low percentage of IgM could be related to the time interval between vaccination and sample measure.