NCT07049497

Study of Immune Response in Subjects Vaccinated Against SARS-CoV-2 Infection

Monocentric Retrospective Observational Study on Immune Response in Biological Samples Belonging to Subjects Vaccinated Against SARS-CoV-2 Infection

• Status: Completed
• Phase: —
• Study type: Observational
• Enrollment: 127 (actual)
• Sponsor: IRCCS San Raffaele · Academic / Other
• Sex: All
• Age: 18 Years
• Healthy volunteers: Accepted

Summary

Twelve months after the first SARS-CoV-2 cases in Wuhan, the FDA approved the first COVID-19 vaccine (Pfizer-BioNTech). Early studies on healthcare workers showed that antibody levels, especially against the Spike protein, declined within six months, particularly in those without prior infection. However, previously infected individuals had stronger and longer-lasting responses. The vaccine induces a Th1-type T cell response, linked to milder disease, and activates follicular helper T cells and B cell responses, although antibody levels drop over time. Immune responses also differ by sex, with females showing stronger humoral responses. Key priorities include understanding humoral fluctuations, characterizing cellular immunity, and correlating both responses.

Conditions

• SAR-CoV-2
• Cellular Immune Response
• Antibody Response

Interventions

Type	Name	Description
OTHER	Evaluation of the T cell response in terms of IFN-γ measured by ELISpot	The evaluation of the T cell response will be performed by quantifying the frequencies of SARS-CoV-2-specific T cells producing IFN-γ using an enzyme-linked immunospot assay (ELISpot), with cryopreserved PBMC collected at the designated timepoints (T0, T1, T2, T3, and T4)

Timeline

• Start date: 2022-06-28
• Primary completion: 2022-07-20
• Completion: 2024-05-15
• First posted: 2025-07-03
• Last updated: 2025-07-14

Locations

1 site across 1 country: Italy