COVID-19 Antibody Response Dynamics in Vaccinated Healthcare Workers

Researchers from the University of Bologna in Italy examined the longitudinal dynamics of anti-nucleocapsid and anti-spike antibody responses to SARS-CoV-2 infection and mRNA vaccination in 81,878 serum samples from 23,616 healthcare workers across five European countries. The study employed a shifted transformation method for data normalization and utilized the Bass diffusion model to predict antibody titer dynamics influenced by both internal factors such as immune activation and external factors like infection and vaccination. The findings indicate that Anti-N antibodies exhibited a rapid decline, while anti-S antibodies demonstrated prolonged persistence, with a significant decline in anti-S levels observed 3-5 months post-vaccination.

Key Takeaways:

• The study examined the longitudinal dynamics of anti-nucleocapsid and anti-spike antibody responses to SARS-CoV-2 infection and mRNA vaccination in 81,878 serum samples from 23,616 healthcare workers across five European countries.
• The Bass diffusion model effectively captured variations in antibody titers, analyzed through demographic factors such as gender, age, and job role, while thoroughly accounting for pre-infection status.
• Anti-N antibodies exhibited a rapid decline, while anti-S antibodies demonstrated prolonged persistence, with adaptive immunity characterized by the dominance of internal factors effects relative to external ones achieved in most groups after the fourth dose.
• A significant decline in anti-S levels was observed 3-5 months post-vaccination.
• The findings emphasize the significance of the Bass Method in predicting vaccine-induced, hybrid immune responses and detecting adaptive immunity by overcoming limitations in internal factor data.
• The study highlights the Bass Method's value in predicting vaccine-induced and hybrid immunity, effectively addressing internal factor data gaps to enhance vaccination and infection control strategies.

Statistics:

• 81,878 serum samples were analyzed from 23,616 healthcare workers across five European countries.
• 25% of samples originated from individuals with confirmed prior infection.
• Anti-S levels demonstrated prolonged persistence, with a significant decline observed 3-5 months post-vaccination.
• Adaptive immunity characterized by the dominance of internal factors effects relative to external ones was achieved in most groups after the fourth dose.

Sources:

• Vacines, 2025,13(6):611 (Vaccines - http://www.mdpi.com/journal/vaccines)
• Department of Economics, University of Bologna, 40126 Bologna, Italy
• PMID: 10.3390/vaccines13060611
• A free version of this journal article is available at https://doi-org.sdpl.idm.oclc.org/10.3390/vaccines13060611