Abstract
Vaccination has emerged as the most effective tool in the battle against COVID-19. To optimize vaccination protocols, a deeper understanding of the immune response to vaccination, including influential factors and its duration, is essential. This study aimed to assess the humoral response in vaccinated individuals with or without prior SARS-CoV-2 infection. A prospective observational study was conducted across 14 private healthcare structures in Greece. Anti-spike IgG titers were measured at different timepoints following the initial vaccination and booster doses of the BNT162b2, mRNA-1273, ChAdOx1 nCoV-19, and Ad26.COV2.S vaccines. A total of 505 participants were included in the first phase, evaluating the humoral response after the initial vaccination, and 311 participants were involved in the second phase, assessing the effects of booster vaccination. All vaccines elicited high anti-S IgG titers initially, followed by a subsequent decline that was addressed by the booster vaccination. The humoral response was sustained up to one year after the booster vaccination. mRNA vaccines induced higher anti-S IgG titers compared to vector vaccines, with mRNA-1273 eliciting higher titers than BNT162b2. Vaccination resulted in higher antibody titers than natural infection alone; however, convalescent patients who received vaccination had significantly higher anti-S IgG titers compared to those who received the booster vaccine without previous SARS-CoV-2 infection. Lower antibody titers were observed in men and older patients (>51.5 years old), as well as smokers, although the decline rate was lower in these subgroups. These results underscore the importance of booster doses and reveal the potential influence of age, gender, smoking habits, and vaccine type on varying humoral responses. Long-term monitoring of antibody persistence, evaluation of cellular immune responses, and assessment of vaccine efficacy against emerging variants should be considered to enhance our understanding of immunity dynamics and inform vaccine development and deployment strategies.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
