Quantifying low-frequency revertants in oral poliovirus vaccine using next generation sequencing.

Spontaneous reversion to neurovirulence of live attenuated oral poliovirus vaccine (OPV) serotype 3 (chiefly involving the n.472U>C mutation), must be monitored during production to ensure vaccine safety and consistency. Mutant analysis by polymerase chain reaction and restriction enzyme cleavage (MAPREC) has long been endorsed by the World Health Organization as the preferred in vitro test for this purpose; however, it requires radiolabeling, which is no longer supported by many laboratories.