Bolotin S, Tran V, Osman S, et al. - Researchers sought to determine how antibody decline affect SARS-CoV-2 seroprevalence estimates via analyzing 21,676 residual specimens from Ontario, Canada collected between March-August, 2020. Testing specimens orthogonally using the Abbott (anti-nucleocapsid) and then the Ortho (anti-spike) assays, seroprevalence estimates ranging from 0.4%-1.4% were identified despite ongoing disease activity. They observed decrease in the geometric mean concentration (GMC) of antibody-positive specimens, and increase in the GMC of antibody-negative specimens, over time. Each month, a decrease in the association between the two tests was noted, indicating anti-N antibody decline. Sixteen percent increase in positive specimens was observed with lowering the Abbott antibody index cut-off from 1.4 to 0.7.