Humoral response against spike protein enhanced by fifth and sixth COVID-19 mRNA vaccine in the uninfected and infected subjects

Abstract

Antibody obtained by the coronavirus disease-19 (COVID-19) mRNA vaccine declines over time, and additional vaccinations are offered. It is not clear how repeated vaccination affects humoral immunity in uninfected individuals. We analyzed immunoglobulin G for spike protein (S-IgG) titers in COVID-19 uninfected and infected individuals vaccinated up to six times. The geometric mean S-IgG titers were 575.9 AU/mL and 369.0 AU/mL in those who received 6 and 5 doses less than 180 days after the last vaccination in uninfected subjects. In the 180–360 days after the last vaccination, the geometric mean S-IgG titers were 237.9 AU/mL and 128.6 AU/mL in the uninfected subjects who underwent five-dose and four-dose groups, respectively. Multivariate analysis showed that S-IgG titer increased 1.261-fold with each additional dose of mRNA vaccine. The S-IgG titers were 2.039-fold higher in the COVID-infected subjects compared to uninfected subjects. The positivity rate of nucleocapsid antibodies, suggesting a history of COVID-19, decreased 82% and 30% of COVID-infected cases after 180 and 360 days of infection, respectively. This result suggested that repeated vaccination with the COVID-19 mRNA vaccine may increase antibody titer in uninfected subjects.

Humoral response against spike protein and fifth and sixth COVID-19 mRNA vaccine in the uninfected and infected subjects: What should be for the seventh dose?

“…Additional doses should be administered based on emerging scientific evidence, such as data on vaccine effectiveness, immune response, safety, and the prevalence of new variants. Given the current study’s findings that the positivity rate of nucleocapsid antibodies, indicating a history of COVID-19, decreased 82% and 30% of COVID-infected cases after 180 and 360 days of infection, respectively, 1 the seventh dose of the vaccine should still play a role in boosting immunity. It is critical to weigh the benefits and risks, as well as potential ethical concerns, such as ensuring equitable global access to vaccines.…”

“…Dear Editor, we would like to share ideas on the publication “Humoral response against spike protein enhanced by fifth and sixth COVID-19 mRNA vaccine in the uninfected and infected subjects.” 1 The study’s shortcomings, as mentioned in the first paragraph, include a lack of information about the specific mRNA vaccine used, a small sample size, and a focus on only one type of antibody (S-IgG titers). Furthermore, the study does not provide information on the immune response’s durability or the effectiveness of the additional vaccinations in preventing COVID-19 infection or severe disease.…”