The efficacies of these vaccines especially against heterologous strains remain questionable :
With the development of PRRSV reverse genetics systems and the acquisition of new understanding on anti - PRRSV immunity , rational design of the next generation of PRRSV vaccines can now be explored .
The efficacies of these vaccines especially against heterologous strains remain questionable :
With the development of PRRSV reverse genetics systems and the acquisition of new understanding on anti - PRRSV immunity , rational design of the next generation of PRRSV vaccines can now be explored .