Evaluation of Antibody Level of COVID-19 Vaccines among the Staff of the Razi Teaching Hospital in Qaemshahr at Least 6 Months after Receiving the Third Dose

Abstract

Background and purpose: Although various vaccines have been produced to provide immunity against COVID-19, these vaccines do not provide lifelong immunity, and over time, their level of immunity diminishes. Considering that at least 50% of the population must be immune to prevent the chain of transmission of COVID-19, we conducted this study to measure the level of immunity against this virus after at least 6 months of the third dose injection among the employees of Razi Hospital, Qaimshahr. Materials and methods: In this analytical observational study, the blood samples of 88 volunteers were used to determine the SARS-Cov-2 RBD antibody. The 18-item self-report questionnaire of the side effects of the COVID-19 vaccine was provided to the participants. Statistical analysis was done with SPSS software (version 0.24). Results: The mean age of the participants was 41 years, and men and women accounted for 36.36% and 63.63% of the samples, respectively. The youngest participant was 23 years old, while the oldest was 72 years old. Comorbidities were found in 21% of the participants. Among the 88 participants, 98.86% had antibody levels higher than the cut-off, which was 5 (RU/ml). Systemic side effects of the third dose included fever (46.5%), myalgia (25%), as well as local reactions of pain (29.5%) and redness (6%). The systemic side effects of the fourth dose were fever (22%), myalgia (12%), and the local reactions were injection site pain (42%) and redness (4%). Conclusion: No significant relationship was found between the investigated variables and the antibody level. However, it was observed that humoral immunity against COVID-19 was present in most of the injectors after 6 months from the third dose injection.

Keywords

• antibody
• covid-19
• sars-cov-2 rbd
• vaccine