Long-term follow-up of antibody and T-cell responses after COVID-19 mRNA vaccination in infection-naïve and infected individuals with focus on breakthrough infections

Individuals with hybrid immunity had significantly higher RBD-IgG levels than infection-naïve subjects up to 23 months post-vaccination when including breakthrough infections, while elevated antibody responses were limited to the first year in those infected pre-vaccination. Differences were more pronounced for antibody than T-cell responses when comparing individuals with and without breakthrough infections.