ABSTRACT Neutralizing titer is a demonstrated correlate of protection across most viral pathogens. The traditional assay to assess neutralization titer is the plaque reduction neutralization test (PRNT), which is generally regarded as slow, subjective, and variable. To conduct large scale clinical vaccine trials, thousands of serum samples from vaccinated individuals are typically assessed in neutralization assays, a scale that is difficult to achieve using live virus in high containment facilities. Optical reporters such as GFP and luciferase encoded in ‘reporter viruses’ are an alternative to PRNT and are more streamlined, safe, and scalable than PRNT assays but still require a week of experimentation. Here we propose to develop a Rapid Reporter Virus (RRV) to assess virus infection and neutralization rapidly and safely. The development of this novel assay is in direct response to our customers’ requests for a better neutralization readout.