In light of global concerns surrounding the disparities in COVID-19 vaccine distribution, there is a growing recognition of the need for strategic booster shots. This study delves into the nuanced dynamics of longitudinal antibody responses post-booster during the Omicron wave within a Japanese cohort, with a particular emphasis on prior infection and booster doses. The prospective cohort, comprising 1763 participants aged 18 and older, each having received at least three vaccine doses, yielded a dataset of 7376 datapoints. Antibody levels were meticulously measured every two months.
COVID-19
Utilizing a Bayesian linear mixed-effects interval-censored model, the study modeled temporal declines in antibody levels after COVID-19 vaccine boosters, taking into account factors such as prior infection status, the number of booster doses, age, sex, underlying conditions, and lifestyle. The results underscore the crucial role of prior infection in enhancing post-booster immunity. Participants with a history of prior infection exhibited a remarkable maintenance of antibody levels over a year, in stark contrast to uninfected individuals whose levels had significantly waned by eight months post-vaccination. Each additional booster dose was correlated with higher baseline antibody levels and slower declines, particularly evident after the third dose.
While factors like female sex, older age, immunosuppressive status, and smoking history were associated with lower baseline post-vaccination antibodies, they did not significantly influence decline rates except for older age in the main model.
The study’s introduction contextualizes the global vaccination landscape, emphasizing the disparities in booster adoption across different regions. With Japan leading in booster shots and South America lagging behind, the study also draws attention to the COVID-19 case fatality risks, which are significantly lower in regions with widespread booster adoption. The World Health Organization’s concerns about vaccine distribution disparities are highlighted, underscoring the urgency for tailored, efficient, and personalized booster strategies.
In this context, the study addresses the growing calls for clarification on individuals eligible for booster shots. It draws attention to the potential of hybrid immunity in individuals with prior infection and explores how the trajectory of antibody levels after vaccination varies with this history, particularly during the Omicron wave. Despite the WHO’s recommendation for a third (booster) shot, there is a notable lack of analyses on post-booster outcomes, and the study acknowledges the potential emergence of new variants, suggesting the likelihood of routine booster recommendations. However, the clinical importance of repeated (fourth or fifth) booster shots following a third shot remains unassessed, emphasizing the need for further research.
The participant characteristics and antibody dynamics sections provide a detailed overview of the study’s methodology, ensuring transparency and clarity in the research process. The linear regression analysis further reinforces the findings, illustrating that individuals with a prior infection maintain more sustained antibody levels over time compared to those without prior infection.
In conclusion, the study not only contributes valuable insights into the intricate dynamics of antibody responses post-booster but also emphasizes the significance of tailored booster strategies, taking into account factors such as prior infection, age, sex, health conditions, and lifestyle. As the world navigates the ongoing challenges of the pandemic, strategic booster approaches informed by comprehensive research will be crucial in addressing global vaccine distribution disparities and ensuring the effectiveness of vaccination efforts.
