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The following is a summary of “Development of antibody levels and subsequent decline in individuals with vaccine induced and hybrid immunity to SARS-CoV-2,” published in the September 2024 issue of Infectious Diseases by Reekie et al.

Researchers conducted a retrospective study to compare antibody trajectories between individuals with SARS-CoV-2 hybrid and vaccine-induced immunity.

They included Danish adults who received 3 doses of the BTN162b2 or mRNA-1237 vaccine before their first vaccination (Day 0) and measured SARS-CoV-2 anti-spike IgG levels before each vaccine dose, at day 90, 180, 28 days after the 3rd vaccination (Day 251), day 365, and the 4th vaccination (Day 535). The results of SARS-CoV-2 PCR were extracted from the national microbiology database and used mixed-effect multivariable linear regression to investigate the impact of hybrid immunity (stratified into 4 groups: no hybrid immunity, PCR+ before 3rd dose, PCR+ after 3rd dose and before Day 365, and PCR+ after Day 365) on anti-spike IgG trajectories.

The results showed 4,936 individuals were included, with 47% developing hybrid-immunity. Anti-spike IgG levels increased in all groups at day 251, with the highest levels in those PCR+ before 3rd dose (Geometric Mean; 535,647AU/mL vs. 374,665AU/mL with no hybrid-immunity, P<0.0001). Additional elevation was observed in participants who developed hybrid immunity after their 3rd dose. Anti-spike IgG levels declined from day 251-535 in individuals without hybrid immunity and those who developed hybrid immunity before their 3rd dose, with a lower rate of decline in those with hybrid immunity.

They concluded that hybrid immunity resulted in higher and more durable antibody trajectories in patients with vaccination.

Source: sciencedirect.com/science/article/pii/S1201971224001826