against COVID-19 based on antigenic distance," was published inOver the past three years, scientists around the world have developed vaccines against the virus. Initially, most vaccines demonstrated high effectiveness in preventing COVID-19, but the protection levels of all vaccines declined over time due to newly emerged variants. Thus, a COVID-19shot is recommended to people who have already completed their initial vaccine series.
However, the process of developing and testing vaccines often lags behind the emergence of new variants. For example, the omicron strain surfaced in November 2021, but the second-phase clinical trial of the vaccine targeting the BA.1 strain began in February 2022. By April 2022, during the mid-term analysis, the strain had evolved into BA.2, and by September 2022, it had already become BA.5. The evolution of SARS-CoV-2 virus demands a new strategy for developing new vaccines to keep up.
Based on research and analysis of immune escape of SARS-CoV-2 virus, the researchers constructed an"antigen distance" model using existing neutralization and sequencing data. This model measured the degree of immune escape of different mutant strains based on the neutralizing abilities of human sera against various strains.
They plotted an antigen map of COVID-19 in terms of"antigenic distance" and explored the protection range of using different strains as booster vaccines, including the ancestral SARS-CoV-2 strain, the SARS-CoV-2 delta strain , the SARS-CoV-2 omicron strain , the SARS-CoV-1 strain, and the Middle East respiratory syndrome coronavirus strain.
To validate their findings, the researchers conducted experiments using human serum samples, which confirmed the model's accuracy. Subsequently, they tested in a