Does the detection of antibody levels know the protective efficacy of the new crown vaccine?

In the past year, the new crown vaccine has provided an important means for epidemic prevention and control

However, there is currently no clinically dedicated tool for detecting neutralizing antibodies after vaccinations with the new crown vaccine; more importantly, the concentration of the new crown neutralizing antibodies will definitely protect the vaccinated from infection, and there is still a lack of recognized standards.

Recently, the top academic journal "Science" published the results of a clinical trial, providing important data on the relationship between the level of antibodies induced by the new crown vaccine and the protection against infection

In this phase 3 clinical trial called COVE, the researchers evaluated the antibodies induced by participants vaccinated with mRNA-1273, a vaccine developed by Moderna

The researchers pointed out that identifying and verifying protection-related immune markers will help us measure the immunity required to fight infection, reliably guide the optimization of the new crown vaccination program, and the clinical evaluation and supervision of more new vaccines in the future Approved

The researchers collected the blood of the test participants after the second shot of the vaccine and 4 weeks after they were vaccinated, and tested the binding antibody (IgG bAb) against the viral spike protein (Spike) and the antibody binding domain (RBD) and neutralization Antibody (IgG nAb)

In previous rhesus monkey challenge experiments, these four antibody markers have been shown to be related to the protection of the vaccine, and can effectively inhibit virus replication after rhesus monkeys are exposed to the new coronavirus

▲The relationship between different antibody levels and the cumulative incidence after vaccination (picture source: reference [1])

The results of the study showed that the evaluated binding antibodies and neutralizing antibodies were negatively related to the risk of COVID-19 within 4 months after the second dose

After 4 weeks of vaccination, the vaccinators whose neutralizing antibody titer levels (50% neutralizing titer test) were 10, 100, and 1000, predicted the vaccine efficacy to be 78%, 91%, and 96%, respectively

▲Using the level of neutralizing antibody titer as an indicator to assess the risk correlation of COVID-19 (picture source: reference [1])

Based on these results, the researchers proposed a continuous model in which the protective efficacy of the vaccine gradually increases as the level of antibody markers increases

Note: The original text has been deleted

Reference

[1] Peter B.

[2] Antibody levels predict vaccine efficacy, new analysis shows.