Measuring COVID-19 Antibodies: A Navy Study

In the fight against COVID-19, scientists are using special tests to measure antibodies in people's blood. One such test is the Vaxarray Coronavirus (CoV) seroassay. This test checks for SARS-CoV-2 IgG antibodies, which are made against three parts of the virus: the full-length spike protein (FLS), the receptor binding domain (RBD), and the S2 extracellular domain (ECD). Previous studies have used reference values that haven't been thoroughly checked. This study, however, used a method called the upper tail of the Student t-distribution to find reliable reference values. The target group was any adult working on a U. S. Navy ship who had been vaccinated against the Wuhan variant. The reference values for the three parts of the virus were found to be 17, 731 for the full-length spike protein, 13, 990 for the RBD, and 9, 096 for the S2 ECD. Using these values, the study was able to tell the difference between antibodies made from vaccines and those made from natural infections. This is important because it helps understand how well vaccines are working. The study also provides the method and the computer code so that others can find reference values for different antibody tests in the future.