Longitudinal immune kinetics of COVID-19 booster versus primary series vaccination: Insight into the annual vaccination strategy.

Background: Data on the durability of booster dose immunity of COVID-19 vaccines are relatively limited.
Methods: Immunogenicity was evaluated for up to 9-12 months after the third dose of vaccination in 94 healthy adults.
Results: Following the third dose, the anti-spike immunoglobulin G (IgG) antibody response against the wild-type was boosted markedly, which decreased gradually over time. However, even 9-12 months after the booster dose, both the median and geometric mean of anti-spike IgG antibody levels were higher than those measured 4 weeks after the second dose. Breakthrough infection during the Omicron-dominant period boosted neutralizing antibody titers against Omicron sublineages (BA.1 and BA.5) and the ancestral strain. T-cell immune response was efficiently induced and maintained during the study period.
Conclusions: mRNA vaccine booster dose elicited durable humoral immunity for up to 1 year after the third dose and T-cell immunity was sustained during the study period, supporting an annual COVID-19 vaccination strategy.
Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Joon Young Song reports financial support was provided by Korea Disease Control and Prevention Agency. Joon Young Song reports a relationship with Korea Disease Control and Prevention Agency that includes: board membership.
(© 2024 The Authors.)