Due to the unavailability of any specific countermeasure, the constantly spreading COVID-19 pandemic could only be partially and temporarily slowed down by implementing regional lockdowns that force people to stay at home and prevent their movement. With the progression of the pandemic, a considerable subset of the population would have acquired post-infection immunity and the tests that reveal the post-infection immune status of individuals are the need of the hour. A credible test, which accurately identifies the protected, can offer an immunity passport for the individual to be freed from the lockdown and resume routine activities without the fear of getting infected. At present, the semi-quantitative neutralization test (NT) and the quantitative plaque reduction neutralization test (PRNT) identifying the presence of anti-SARS-CoV-2 neutralizing antibodies (nAbs) are the only foolproof methods available for this purpose. However, practical feasibility of these highly specific tests is weighed down by drawbacks such as low throughput, long turnaround time (TAT), and the need for a specialized laboratory setup with biosafety level 3 (BSL3) facilities to handle the live viruses used in these tests (Cao et al., 2020).
