A third SARS-CoV-2 spike vaccination improves neutralization of variants-of-concern

Area of Science:

• Immunology
• Virology
• Vaccinology

Background:

• Emerging SARS-CoV-2 variants exhibit increased resistance to antibody neutralization, challenging COVID-19 pandemic control.
• Current vaccines, while effective against the original strain, may have reduced efficacy against neutralization-resistant variants of concern (VOC).

Purpose of the Study:

• To evaluate the impact of a third vaccination with Wuhan-based Spike vaccines on neutralizing antibody responses against SARS-CoV-2 VOC.
• To determine if a booster dose can overcome reduced vaccine efficacy against variants like Beta.

Main Methods:

• Assessment of neutralizing antibody titers in mice, rabbits, and non-human primates following a third immunization.
• Testing antibody responses against multiple VOC, including Alpha, Beta, Gamma, and Delta.

Main Results:

• A third immunization significantly improved neutralizing antibody titers against all tested VOC (Alpha, Beta, Gamma, Delta).
• Post-third vaccination neutralization levels against the Beta variant were comparable to pre-booster levels against the original SARS-CoV-2 strain.

Conclusions:

• A third dose of Wuhan-based Spike vaccine can effectively enhance neutralizing antibody responses against SARS-CoV-2 VOC.
• Booster vaccination may be a viable strategy to mitigate the impact of reduced vaccine efficacy against emerging variants.