Publication date: Oct 09, 2024

SARS-CoV-2 is continually evolving with new variants to evade protective immunity and cause new infections. This study aimed to assess infection-acquired immunity and hybrid immunity against re-infection or severe COVID-19. During 2020-2023, we collected 890 serum samples from individuals infected with SARS-CoV-2 variants including wild type, D614G, Alpha, Delta, BA. 1, BA. 2, BA. 2.76, BA. 5.2, BF. 7, XBB, and EG. 5. The levels of serum neutralizing antibodies (NAbs) against 18 diverse SARS-CoV-2 variants were determined using a bead-based high-throughput broad neutralizing-antibody assay. In the initial wave of the COVID-19 pandemic, >75% of the patients demonstrated robust NAb responses against the ancestral SARS-CoV-2, during a period when vaccines were not yet available. After the emergence of the Omicron variant, the seroprevalence of anti-Omicron NAbs among the patients increased rapidly. By April 2023, when XBB variant was predominant, approximately 80% of the patients demonstrated > 50% neutralization against the highly immune-evasive XBB lineages. Three serotypes of SARS-CoV-2, namely non-Omicron, Omicron, and XBB serotypes, were identified, with the strong likelihood of further changes occurring as the virus mutating. Generally, NAbs elicited by a previous serotype could not typically effectively protect against another serotype that emerges later in the evolutionary stages. Our results firstly demonstrated the synergistic evolution between host immunity and SARS-CoV-2 variants in the real world, which would be helpful to develop future vaccines and public health strategies.

Semantics

Original Article