Whether simple serological tests will be able to predict neutralizing antibody titers and immunity to SARS-CoV-2 is usually yet to be determined. serological Fosaprepitant dimeglumine measurements and functional neutralization activity, some assays maintained an ability to predict neutralizing titers, even against variants of concern. == Interpretation == The ability of high throughput serological assays to predict neutralizing antibody titers is likely crucial for evaluation of immunity at the population scale. These data will facilitate the selection of the most suitable assays as surrogates of functional neutralizing activity and suggest that such measurements may have utility in clinical practice. == Introduction == The world has experienced an unprecedented pandemic following the emergence of severe acute respiratory coronavirus 2 (SARS-CoV-2). Hundreds of thousands have died and the repercussions have affected every aspect of life. The amazing mobilization of the scientific community in response to the pandemic has led to the rapid development of safe and effective vaccines, as well as reagents and assays to aid in the detection and mitigation of computer virus spread. An early prominent issue in the pandemic was the accurate identification of infected individuals at a large scale. While PCR-based assays remain a reliable and sensitive test for contamination they are not amenable to mass populace screening. Thus, serological assays, despite limitations,13have been instrumental for surveillance and providing selection criteria to recruit vaccine trial participants and convalescent plasma donors. Monitoring antibody titers is necessary to measure the magnitude and longevity of immune responses induced by natural contamination or vaccination. As immune responses to SARS-CoV-2 antigens are increasingly elicited by contamination and/or vaccination, the measurement of antibody titers and the ability of such measurements to predict protection from contamination or disease will be of great importance. Whether simple serological tests will be able to predict neutralizing antibody titers and immunity to SARS-CoV-2 is usually yet to be determined. Moreover, as antibodies both mature, acquiring greater affinity, while total levels decline,46and new SARS-CoV-2 variants emerge, the predictive value of serological assessments based on the prototype viral strain will need to be evaluated. A number of high-throughput serological assays are routinely used to detect antibodies against nucleocapsid (N) or spike (S) viral antigens. These assays were initially designed to provide a positive or unfavorable test result, but they also generate quantitative measurements of antibody Fosaprepitant dimeglumine levels. Prior studies of how these quantitative serological values correlate with neutralizing antibodies titers have yielded variable results79. Importantly, the sensitivity of the assays as diagnostic tools and their predictive value for immune parameters several months after contamination and against variants of concern has not been assessed. We present a longitudinal study of COVID-19 recovered patients over 6 months post-infection, evaluating the diagnostic sensitivity of ten different serological assays and their ability to predict neutralizing antibody activity against SARS-CoV-2. == Results == A previously reported8cohort of participants that developed moderate symptoms following SARS-CoV-2 infection, was repeatedly sampled, up to 7.2 months post-infection, to evaluate how neutralizing antibody levels correlate over time with antibodies measured using ten high throughput serological assays. Neutralizing antibody titers were measured at up to five visits for each participant using a pseudovirus neutralization assay that correlates well with neutralization against Fosaprepitant dimeglumine authentic SARS-CoV-210. Consistent with prior studies4,8,11,12, the half-maximal neutralizing titers (NT50) declined over time in the majority of patients (Physique 1A,B). The most significant rate of decrease, approximately 25%, was observed between the early visits Fosaprepitant dimeglumine reaching a 45% decrease in NT50 by visit 3, approximately 70 days post-infection (Physique 1C). Thereafter the rate of decrease became HDM2 less pronounced and NT50 values at visits 4 and 5, at approximately 37 months post-infection, appeared to stabilize at ~30% of the levels observed within the first 2 months post-infection (Physique 1B,C). NT50 values Fosaprepitant dimeglumine were higher in male than female participants at visit 1, but the overall rate of NT50 decline from the first to the last visit was greater for male participants (supplementary.