Fig 4. Long-term stability of virus and empty capsid preparations compared to the IPV reference.

Proportion of D antigen reactivity remaining after incubation at 37°C relative to incubation at 4°C. Aliquots of IPV, virus and empty capsid samples were incubated at 37°C and samples were removed at intervals and analysed by D Antigen ELISA; reactivity is expressed relative to samples incubated at 4°C for the same period. (A) Type 1, (B) Type 2, (C) Type 3.