Rapid lateral flow tests for the detection of SARS-CoV-2 neutralizing antibodies

Background: Rapid Lateral Flow Test (LFT) has been broadly utilized in detection or diagnosis of numerous disease-related antigens and antibodies. It is the most popular format of point-of-care test (POCT) and quickest and easiest way to detect a targeted molecule. In the combat against COVID-19 pandemic, hundreds of POCTs have been developed and are commercially available now. They are designed to detect either a SARS-CoV-2 viral antigen or IgG and IgM antibodies binding to it. Among the binding antibodies, a special type of functional antibodies that block the interaction between SARS-CoV-2 virus and its human receptor, neutralizing antibodies (NAbs), are of particular interest to public as well as in vaccination management. However as of today, POCTs for the detection of SARS-CoV-2 NAbs remain under late stage of development. Scope and method:In this review, we first summarize the importance of awareness and monitoring of SARS-CoV-2 NAbs in the combat against COVID-19 pandemic. Secondly, we compare the available methods for the detection of SARS-CoV-2 NAbs. Next, we describe challenges in the development of a rapid lateral flow test for the detection of SARS-CoV-2 NAbs. Finally, we outline its product formats and applications in research and in disease management. Conclusion:Vaccine effectiveness is unknown for an individual unless measured. NAb level is the most viable measurement for vaccine effectiveness or immunity. A broadly accessible NAb POCT is urgently needed.